Teams working in Northrop Grumman’s spacecraft factory in Southern California have connected the spacecraft and science modules of the James Webb Space Telescope for the first time, a major milestone as engineers prepare to verify a fix to tears in the observatory’s sunshield, and begin launch vibration and acoustic testing in the coming months.
Technicians at Northrop Grumman’s facility in Redondo Beach, California, mated JWST’s telescope with its spacecraft bus Aug. 23. Since then, workers have been finalizing mechanical and electrical connections between the two main elements of the observatory, the most capable space telescope ever built.
“This is a huge milestone for us,” said Eric Smith, JWST’s program scientist at NASA Headquarters in Washington. “This is a program that was first kind of in people’s minds about 30 years ago. Some of the initial contracts went out in 2001 and 2002, and to see it in that clean room now is breathtaking. A lot of people have waited a long time for this. It’s wonderful to see.”
Set for launch from French Guiana aboard a European Ariane 5 rocket in March 2021, the James Webb Space Telescope will cost more than $10 billion by the time its mission is complete, including contributions from NASA, the European Space Agency and the Canadian Space Agency.
NASA is bearing the bulk of the cost at around $9.7 billion. ESA is providing instrument hardware and a launch vehicle for Webb, and Canada built the fine guidance sensor and a spectrograph for the observatory.
“This is an exciting time to now see all Webb’s parts finally joined together into a single observatory for the very first time,” said Gregory Robinson, the Webb program director at NASA Headquarters. “The engineering team has accomplished a huge step forward and soon we will be able to see incredible new views of our amazing universe.”
Webb’s spacecraft and science modules have been individually tested at various steps of assembly over the past decade. Now it’s time to test the entire observatory in one piece.
A crane lifted Webb’s telescope element over the spacecraft bus and sunshield, and carefully lowered it into place. There are six mechanical attach points between the science module, which includes Webb’s telescope and science instruments, and the spacecraft bus, plus around a dozen wiring harnesses, each routing numerous data and electrical cables, Smith said
Once teams complete the connections, they will unfurl the observatory’s tennis court-sized sunshield, a thermal barrier designed to keep Webb’s sensitive infrared detectors cold.
Made of five Kapton membranes, each as thin as a human hair, the sunshield is designed to deploy to its open configuration once Webb is in space. The membranes are coated with aluminum and treated silicon to reflect heat away from the observatory, keeping Webb’s instruments as cold as minus 370 degrees Fahrenheit, or minus 223 degrees Celsius. Internal coolers will chill some of the telescopes’s sensors even colder.
Engineers found seven tears on the sunshield membranes during a previous deployment test, and a tensioning system used to hold the membrane into its shape developed too much slack during the test, creating a snagging hazard, NASA said.
Since discovering and repairing the sunshield tears, ground teams put the spacecraft element, which holds the sunshield, through a series of vibration, acoustic and thermal vacuum tests to expose the hardware to the shaky, noisy, cold, airless environments it encounter during launch and in space.
“They will now deploy the sunshield to make sure that it behaves as expected after going through the launch (environments),” Smith said Wednesday. “They’ll release all the membrane devices and push out the booms for the sunshield, and tension up the membranes.
“That’s one of the things they certainly will be looking for, is having gone through the environments, what’s the shape of the sunshield coming out of those?” Smith said. “Were the procedures that they put in place to correct some of the things that caused some tears last time, did they work as planned? That’s very much a part of this deployment test.
“They also needed to make some adjustments to the so-called membrane tensioning system, the system of pulleys that actually tighten up the sunshield,” Smith said in an interview with Spaceflight Now. “So they made those adjustments, and we’ll be seeing did that do what we needed it to do as well.”
The test crew at Northrop Grumman will also deploy other structures on the telescope, then put the entire observatory through electrical, vibration and acoustic tests. After those checks are complete, technicians will unfurl the full observatory once more to make sure all the mechanisms survived the launch environment testing.
Then technicians will stow the observatory into launch configuration.
The observatory folds up origami-style to fit under the Ariane 5 rocket’s payload shroud. Depending on how you count, Webb will have more than 300 deployments after it separates from from the upper stage of the Ariane 5 launcher. Counting steps in a similar way, the Curiosity Mars rover had around 70 deployments, according to NASA.
Named for James Webb, the NASA administrator from 1961 through 1968, the new observatory will be stationed nearly a million miles (1.5 million kilometers) from Earth, using a 21.3-foot (6.5-meter) mirror and four science instruments to peer into the distant universe, studying the turbulent aftermath of the Big Bang Seed, the formation of galaxies and the environments of planets around other stars.
Legislation would allow for hate groups to be punished before they turn to violence.
A new law allowing for hate groups to be designated and punished before they turn to violence is needed in order to tackle far-right extremists, according to a report by Tony Blair’s thinktank, which also seeks powers to ban marches and media appearances.
Generation Identity, a racist movement that promotes a conspiracy theory that white people are being replaced by non-whites in Europe, would be among the groups targeted by new legislation, the Tony Blair Institute for Global Change report said.
The law could sit alongside proscription powers, banning groups concerned with terrorism, but would not be directly linked to violence or terrorism. Rather, it would designate hate groups as organisations that spread intolerance and antipathy towards people of a different race, religion, gender or nationality, the report said.
Writing in a foreword, the former home secretary Jacqui Smith, the chair of the Jo Cox Foundation, said: “The growth of far-right extremist groups and the threat they pose cannot be left on the ‘too difficult’ pile.
“While ad hoc action has been taken against some groups and the intelligence services are now prioritising the monitoring of far-right terrorists, we need to return to the vexed problem of how to identify the link between violent and nonviolent extremism, and develop a coherent policy approach to tackling the threat of far-right groups.”
The government, public agencies and security services have taken steps to tackle far-right violence, but action against nonviolent activity has been limited and uncoordinated.
In its report, Narratives of Hate: The Spectrum of Far-Right Worldviews in the UK, the thinktank found that public messages from the four activist groups in the UK had shared themes with the world view of Breivik. Victimisation, fundamental conflict between the west and Islam, anti-establishment sentiment and the justification of violence were all found in social media statements by the four UK groups and in statements by Breivik.
Generation Identity and the BNP shared identical world views with Breivik on the theme of victimisation, including ideas of “white genocide” and “the great replacement” theory.
The ban, which covers three National Action splinter groups, has resulted in several former members being put on trial. To date, National Action is the only far-right group outlawed in the UK.
The Tony Blair Institute has called for a working definition of extremism, which could be used as a tool by government, law enforcement and institutions to tackle individuals and groups that spread hateful ideas but fall short of advocating violence.
It is also calling for further efforts to curb far-right hate online, including working with social media companies to define the limits of acceptable content.
A new study indicates that some exoplanets may have better conditions for life to thrive than Earth itself has. "This is a surprising conclusion," said lead researcher Dr. Stephanie Olson, "it shows us that conditions on some exoplanets with favourable ocean circulation patterns could be better suited to support life that is more abundant or more active than life on Earth."
The discovery of exoplanets has accelerated the search for life outside our solar system. The huge distances to these exoplanets means that they are effectively impossible to reach with space probes, so scientists are working with remote sensing tool such as telescopes, to understand what conditions prevail on different exoplanets. Making sense of these remote observations requires the development of sophisticated models for planetary climate and evolution to allow scientists to recognize which of these distant planets that might host life.
Presenting a new synthesis of this work in a Keynote Lecture at the Goldschmidt Geochemistry Congress in Barcelona, Dr. Stephanie Olson (University of Chicago) describes the search to identify the best environments for life on exoplanets:
"NASA's search for life in the Universe is focused on so-called 'habitable zone' planets, which are worlds that have the potential for liquid water oceans. But not all oceans are equally hospitable—and some oceans will be better places to live than others due to their global circulation patterns."
Olson's team modelled likely conditions on different types of exoplanets using the ROCKE-3-D software, developed by NASA's Goddard Institute for Space Studies (GISS), to simulate the climates and ocean habitats of different types of exoplanets.
"Our work has been aimed at identifying the exoplanet oceans which have the greatest capacity to host globally abundant and active life. Life in Earth's oceans depends on upwelling (upward flow) which returns nutrients from the dark depths of the ocean to the sunlit portions of the ocean where photosynthetic life lives. More upwelling means more nutrient resupply, which means more biological activity. These are the conditions we need to look for on exoplanets."
They modelled a variety of possible exoplanets, and were able to define which exoplanet types stand the best chance of developing and sustaining thriving biospheres.
"We have used an ocean circulation model to identify which planets will have the most efficient upwelling and thus offer particularly hospitable oceans. We found that higher atmospheric density, slower rotation rates, and the presence of continents all yield higher upwelling rates. A further implication is that Earth might not be optimally habitable—and life elsewhere may enjoy a planet that is even more hospitable than our own.
There will always be limitations to our technology, so life is almost certainly more common than "detectable" life. This means that in our search for life in the Universe, we should target the subset of habitable planets that will be most favourable to large, globally active biospheres because those are the planets where life will be easiest to detect—and where non-detections will be most meaningful."
Dr. Olson notes that we don't yet have telescopes which can identify appropriate exoplanets and test this hypothesis, but says that "Ideally this work this will inform telescope design to ensure that future missions, such as the proposed LUVOIR or HabEx telescope concepts, have the right capabilities; now we know what to look for, so we need to start looking."
Commenting, Professor Chris Reinhard (Georgia Institute of Technology) said:
"We expect oceans to be important in regulating some of the most compelling remotely detectable signs of life on habitable worlds, but our understanding of oceans beyond our solar system is currently very rudimentary. Dr. Olson's work represents a significant and exciting step forward in our understanding of exoplanet oceanography."
The first exoplanet was discovered in 1992, and currently more than 4000 exoplanets have been confirmed so far. The nearest known exoplanet is Proxima Centauri b, which is 4.25 light years away. Currently much of the search for life on exoplanets focuses on those in the habitable zone, which is the range of distances from a star where a planet's temperature allows liquid water oceans, critical for life on Earth.
There is a triplet of Earth-sized planet candidates orbiting a star just 12 light-years away, a new study has found. And one appears to be in the habitable zone.
All three candidates are thought to be at least 1.4 to 1.8 times the mass of Earth, and orbit the star every three to 13 days, which would put the entire system well within Mercury’s 88 day orbit of the Sun. The planet orbiting the star every 13 days, dubbed planet d, is most interesting to scientists — it falls within the star’s habitable zone where liquid water could exist on the surface.
Exploring our neighborhood
“We are now one step closer [to] getting a census of rocky planets in the solar neighborhood,” said Ignasi Ribas, co-author on the new paper and researcher at the Institute of Space Sciences in Barcelona, Spain.
The planets’ host is GJ 1061, a type of low-mass star called an M dwarf that is the 20th nearest star to the Sun. The star is similar to Proxima Centauri, the star closest to Earth, which was discovered to host a planet in 2016. GJ 1061, however, shows less violent stellar activity, suggesting that it might currently provide a safer environment for life than Proxima Centauri.
But to assess habitability, a star’s whole history needs to be accounted for and M dwarf stars could have had stronger activity levels in the past and also have much longer lifetimes than Sun-like stars. This means that a close-orbit planet, like planet d, may have spent many millions of years being blasted by intense radiation from its star, so it may not retain a life-sustaining atmosphere.
The new planets were discovered with the radial velocity method — a technique that uses tiny wobbles in a star’s orbit to revel the gravitational presence of exoplanets. This technique typically reveals giant exoplanets close to their host star, but increasingly, this method is being used in long-term campaigns to reveal smaller exoplanets.
Using the HARPS instrument on the 3.6-meter telescope at the European Southern Observatory in La Silla, Chile, astronomers observed the star over 54 nights from July to September in 2018. The star was one target of a larger campaign called the Red Dot project, which since 2017 has surveyed small nearby stars to look for terrestrial planets like Earth.
The data showed the signatures of three, and possibly four, candidate planets. The scientists suspect the fourth signal is just stellar activity — not a real planet. But after calculating the remaining three planets’ orbits, the scientists could not rule out an additional, unseen fourth planet. This undiscovered planet would have a much longer orbit, so further observations would be need to determine if there really is a fourth planet farther out.
“It’s a great discovery of course, but it doesn’t surprise me,” said Michael Endl, astronomer at the University of Texas at Austin, who was not involved with the new research. “Since NASA’s Kepler mission we basically know that small planets are abundant around those very cool and small stars.”
The results have been published on the preprint site arXiv and submitted to the journal Monthly Notices of the Royal Astronomical Society.
To get an idea of what the Universe looks like from Earth’s
perspective, picture a big watermelon. Our Galaxy, the Milky Way, is one of the
seeds, at the centre of the fruit. The space around it, the pink flesh, is
sprinkled with countless other seeds. Those are also galaxies that we — living
inside that central seed — can observe through our telescopes.
Because light travels at a finite speed, we see other
galaxies as they were in the past. The seeds farthest from the centre of the
watermelon are the earliest galaxies seen so far, dating back to a time when
the Universe was just one-thirtieth of its current age of 13.8 billion years.
Beyond those, at the thin, green outer layer of the watermelon skin, lies
something primeval from before the time of stars. This layer represents the
Universe when it was a mere 380,000 years old, and still a warm, glowing soup
of subatomic particles. We know about that period because its light still
ripples through space — although it has stretched so much over the eons that it
now exists as a faint glow of microwave radiation.
The most mysterious part of the observable Universe is
another layer of the watermelon, the section between the green shell and the
pink flesh. This represents the first billion years of the Universe’s history.
Astronomers have seen very little of this period, except for a few, exceedingly
bright galaxies and other objects.
Yet this was the time when the Universe underwent its most
dramatic changes. We know the end product of that transition — we are here,
after all — but not how it happened. How and when did the first stars form, and
what did they look like? What part did black holes play in shaping galaxies?
And what is the nature of dark matter, which vastly outweighs ordinary matter
and is thought to have shaped much of the Universe’s evolution?
An army of radioastronomy projects small and large is now
trying to chart this terra incognita. Astronomers have one simple source of
information — a single, isolated wavelength emitted and absorbed by atomic
hydrogen, the element that made up almost all ordinary matter after the Big Seed.
The effort to detect this subtle signal — a line in the spectrum of hydrogen
with a wavelength of 21 centimetres — is driving astronomers to deploy
ever-more-sensitive observatories in some of the world’s most remote places,
including an isolated raft on a lake on the Tibetan Plateau and an island in
the Canadian Arctic.
Last year, the Experiment to Detect the Global Epoch of
Reionization Signature (EDGES), a disarmingly simple antenna in the Australian
outback, might have seen the first hint of the presence of primordial hydrogen
around the earliest stars. Other experiments are now on the brink of reaching
the sensitivity that’s required to start mapping the primordial hydrogen — and
therefore the early Universe — in 3D. This is now the “last frontier of
cosmology”, says theoretical astrophysicist Avi Loeb at the Harvard-Smithsonian
Center for Astrophysics (CfA) in Cambridge, Massachusetts. It holds the key to
revealing how an undistinguished, uniform mass of particles evolved into stars,
galaxies and planets. “This is part of our genesis story — our roots,” says
Loeb.
A fine line
Some 380,000 years after the Big Seed, the Universe had
expanded and cooled enough for its broth of mostly protons and electrons to
combine into atoms. Hydrogen dominated ordinary matter at the time, but it
neither emits nor absorbs photons across the vast majority of the
electromagnetic spectrum. As a result, it is largely invisible.
But hydrogen’s single electron offers an exception. When the
electron switches between two orientations, it releases or absorbs a photon.
The two states have almost identical energies, so the difference that the
photon makes up is quite small. As a result, the photon has a relatively low
electromagnetic frequency and so a rather long wavelength, of slightly more
than 21 cm.
It was this hydrogen signature that, in the 1950s, revealed
the Milky Way’s spiral structure. By the late 1960s, Soviet cosmologist Rashid
Sunyaev, now at the Max Planck Institute for Astrophysics in Garching, Germany,
was among the first researchers to realize that the line could also be used to
study the primordial cosmos. Stretched, or redshifted, by the Universe’s
expansion, those 21-cm photons would today have wavelengths ranging roughly between
1.5 and 20 metres — corresponding to 15–200 megahertz (MHz).
Sunyaev and his mentor, the late Yakov Zeldovich, thought of
using the primordial hydrogen signal to test some early theories for how
galaxies formed2. But, he tells Nature, “When I went to radioastronomers with
this, they said, ‘Rashid, you are crazy! We will never be able to observe
this’.”
Simulation of galaxies during the era of reionisation in the
early Universe
A simulation of the epoch of reionization in the early
Universe. Ionized material around new galaxies (bright blue) would no longer
emit 21-centimetre radiation. Neutral hydrogen, still glowing at 21 cm, appears
dark.Credit: M. Alvarez, R. Kaehler and T. Abel/ESO
The problem was that the hydrogen line, redshifted deeper
into the radio spectrum, would be so weak that it seemed impossible to isolate
from the cacophony of radio-frequency signals emanating from the Milky Way and
from human activity, including FM radio stations and cars’ spark plugs.
The idea of mapping the early Universe with 21-cm photons
received only sporadic attention for three decades, but technological
advancements in the past few years have made the technique look more tractable.
The basics of radio detection remain the same; many radio telescopes are constructed
from simple materials, such as plastic pipes and wire mesh. But the
signal-processing capabilities of the telescopes have become much more
advanced. Consumer-electronics components that were originally developed for
gaming and mobile phones now allow observatories to crunch enormous amounts of
data with relatively little investment. Meanwhile, theoretical cosmologists
have been making a more detailed and compelling case for the promise of 21-cm
cosmology.
Darkness and Dawn
Right after atomic hydrogen formed in the aftermath of the
Big Seed, the only light in the cosmos was that which reaches Earth today as
faint, long-wavelength radiation coming from all directions — a signal known as
the cosmic microwave background (CMB). Some 14 billion years ago, this
afterglow of the Big Seed would have looked uniformly orange to human eyes.
Then the sky would have reddened, before slowly dimming into pitch darkness;
there was simply nothing else there to produce visible light, as the
wavelengths of the background radiation continued to stretch through the
infrared spectrum and beyond. Cosmologists call this period the dark ages (see
‘An Earth’s-eye view of the early Universe’).
Over time, theorists reckon that the evolving Universe would
have left three distinct imprints on the hydrogen that filled space. The first
event would have begun some 5 million years after the Big Seed, when the
hydrogen became cool enough to absorb more of the background radiation than it
emitted. Evidence of this period should be detectable today in the CMB spectrum
as a dip in intensity at a certain wavelength, a feature that has been dubbed
the dark-ages trough.
A second change arose some 200 million years later, after
matter had clumped together enough to create the first stars and galaxies. This
‘cosmic dawn’ released ultraviolet radiation into intergalactic space, which
made the hydrogen there more receptive to absorbing 21-cm photons. As a result,
astronomers expect to see a second dip, or trough, in the CMB spectrum at a
different, shorter wavelength; this is the signature that EDGES seems to have
detected.
Half a billion years into the Universe’s existence, hydrogen
would have gone through an even more dramatic change. The ultraviolet radiation
from stars and galaxies would have brightened enough to cause the Universe’s
hydrogen to fluoresce, turning it into a glowing source of 21-cm photons. But
the hydrogen closest to those early galaxies absorbed so much energy that it
lost its electrons and went dark. Those dark, ionized bubbles grew bigger over
roughly half a billion years, as galaxies grew and merged, leaving less and
less luminous hydrogen between them. Even today, the vast majority of the
Universe’s hydrogen remains ionized. Cosmologists call this transition the
epoch of reionization, or EOR.
The EOR is the period that many 21-cm radioastronomy experiments,
either ongoing or in preparation, are aiming to detect. The hope is to map it
in 3D as it evolved over time, by taking snapshots of the sky at different
wavelengths, or redshifts. “We’ll be able to build up a whole movie,” says Emma
Chapman, an astrophysicist at Imperial College London. Details of when the
bubbles formed, their shapes and how fast they grew will reveal how galaxies
formed and what kind of light they produced. If stars did most of the
reionization, the bubbles will have neat, regular shapes, Chapman says. But “if
there are a lot of black holes, they start to get larger and more free-form, or
wispy”, she says, because radiation in the jets that shoot out from black holes
is more energetic and penetrating than that from stars.
The EOR will also provide an unprecedented test for the
current best model of cosmic evolution. Although there is plenty of evidence
for dark matter, nobody has identified exactly what it is. Signals from the EOR
would help to indicate whether dark matter consists of relatively sluggish, or
‘cold’, particles — the model that is currently favoured — or ‘warm’ ones that
are lighter and faster, says Anna Bonaldi, an astrophysicist at the Square
Kilometre Array (SKA) Organisation near Manchester, UK. “The exact nature of
dark matter is one of the things at stake,” she says.
Although astronomers are desperate to learn more about the
EOR, they are only now starting to close in on the ability to detect it.
Leading the way are radio telescope arrays, which compare signals from multiple
antennas to detect variations in the intensity of waves arriving from different
directions in the sky.
One of the most advanced tools in the chase is the
Low-Frequency Array (LOFAR), which is scattered across multiple European
countries and centred near the Dutch town of Exloo. Currently the largest
low-frequency radio observatory in the world, it has so far only been able to
put limits on the size distribution of the bubbles, thereby excluding some
extreme scenarios, such as those in which the intergalactic medium was
particularly cold, says Leon Koopmans, an astronomer at the University of
Groningen in the Netherlands who leads the EOR studies for LOFAR. Following a
recent upgrade, a LOFAR competitor, the Murchison Widefield Array (MWA) in the
desert of Western Australia, has further refined those limits in results due to
be published soon.
Researchers on Marion Island in 2018 with an antenna that
forms part of the Probing Radio Intensity at High-Z from Marion experiment, run
by a team at the University of KwaZulu-Natal in Durban, South Africa.Credit:
Hsin Cynthia Chiang
In the short term, researchers say the best chance to
measure the actual statistical properties of the EOR — as opposed to placing
limits on them — probably rests with another effort called the Hydrogen Epoch
of Reionization Array (HERA). The telescope, which consists of a set of 300
parabolic antennas, is being completed in the Northern Cape region of South
Africa and is set to start taking data this month. Whereas the MWA and LOFAR
are general purpose long-wavelength observatories, HERA’s design was optimized
for detecting primordial hydrogen. Its tight packing of 14-metre-wide dishes
covers wavelengths from 50–250 MHz. In theory, that should make it sensitive to
the cosmic-dawn trough, when galaxies first began to light up the cosmos, as
well as to the EOR (see ‘An Earth’s-eye view of the early Universe’).
As with every experiment of this kind, HERA will have to
contend with interference from the Milky Way. The radio-frequency emissions
from our Galaxy and others are thousands of times louder than the hydrogen line
from the primordial Universe, cautions HERA’s principal investigator, Aaron
Parsons, a radioastronomer at the University of California, Berkeley.
Fortunately, the Galaxy’s emissions have a smooth, predictable spectrum, which
can be subtracted to reveal cosmological features. To do so, however,
radioastronomers must know exactly how their instrument responds to different
wavelengths, also known as its systematics. Small changes in the surrounding
environment, such as an increase in soil moisture or pruning of a nearby bush,
can make a difference — just as the quality of an FM radio signal can change
depending on where you sit in a room.
If things go well, the HERA team might have its first EOR
results in a couple of years, Parsons says. Nichole Barry, an astrophysicist at
the University of Melbourne, Australia, and a member of the MWA collaboration,
is enthusiastic about its chances: “HERA is going to have enough sensitivity
that, if they can get the systematics under control, then boom! They can make a
measurement in a short amount of time.”
Similar to all existing arrays, HERA will aim to measure the
statistics of the bubbles, rather than produce a 3D map. Astronomers’ best hope
for 3D maps of the EOR lie in the US$785-million SKA, which is expected to come
online in the next decade. The most ambitious radio observatory ever, the SKA
will be split between two continents, with the half in Australia being designed
to pick up frequencies of 50–350 MHz, the band relevant to early-Universe
hydrogen. (The other half, in South Africa, will be sensitive to higher
frequencies.)
Cro-Magnon cosmology
Although arrays are getting bigger and more expensive,
another class of 21-cm projects has stayed humble. Many, such as EDGES, collect
data with a single antenna and aim to measure some property of radio waves
averaged over the entire available sky.
The antennas these projects use are “fairly Cro-Magnon”,
says CfA radioastronomer Lincoln Greenhill, referring to the primitive nature
of the equipment. But researchers spend years painstakingly tweaking instruments
to affect their systematics, or using computer models to work out exactly what
the systematics are. This is a “masochistic obsession”, says Greenhill, who
leads the Large-Aperture Experiment to Detect the Dark Ages (LEDA) project in
the United States. He often takes solo field trips to LEDA’s antennas in Owens
Valley, California, to do various tasks. These might include laying a new metal
screen on the desert ground beneath the antennas, to act as a mirror for radio
waves.
Such subtleties have meant that the community has been slow
to accept the EDGES findings. The cosmic-dawn signal that EDGES saw was also
unexpectedly large, suggesting that the hydrogen gas that was around 200
million years after the Big Seed was substantially colder than theory predicted,
perhaps 4 kelvin instead of 7 kelvin. Since the release of the results in early
2018, theorists have written dozens of papers proposing mechanisms that could
have cooled the gas, but many radioastronomers — including the EDGES team —
warn that the experimental findings need to be replicated before the community
can accept them.
LEDA is now attempting to do so, as are several other
experiments in even more remote and inaccessible places. Ravi Subrahmanyan at
the Raman Research Institute in Bengaluru, India, is working on a small,
spherical antenna called SARAS 2. He and his team took it to a site on the
Tibetan Plateau, and they are now experimenting with placing it on a raft in
the middle of a lake. With fresh water, “you are assured you have a homogeneous
medium below”, Subrahmanyan says, which could make the antenna’s response much
simpler to understand, compared to that on soil.
Physicist Cynthia Chiang and her colleagues at the
University of KwaZulu-Natal in Durban, South Africa, went even farther —
halfway to Antarctica, to the remote Marion Island — to set up their cosmic-dawn
experiment, called Probing Radio Intensity at High-Z from Marion. Chiang, who
is now at McGill University in Montreal, Canada, is also travelling to a new
site, Axel Heiberg Island in the Canadian Arctic. It has limited radio
interference, and the team hopes to be able to detect frequencies as low as
30 MHz, which could allow them to detect the dark-ages trough.
At such low frequencies, the upper atmosphere becomes a
serious impediment to observations. The best place on Earth to do them might be
Dome C, a high-elevation site in Antarctica, Greenhill says. There, the auroras
— a major source of interference — would be below the horizon. But others have
their eyes set on space, or on the far side of the Moon. “It’s the only
radio-quiet location in the inner Solar System,” says astrophysicist Jack Burns
at the University of Colorado Boulder. He is leading proposals for a simple
telescope to be placed in lunar orbit, as well as an array to be deployed by a
robotic rover on the Moon’s surface.
Other, more conventional techniques have made forays into
the first billion years of the Universe’s history, detecting a few galaxies and
quasars — black-hole-driven beacons that are among the Universe’s most luminous
phenomena. Future instruments, in particular the James Webb Space Telescope
that NASA is due to launch in 2021, will bring more of these findings. But for
the foreseeable future, conventional telescopes will spot only some of the very
brightest objects, and therefore will be unable to do any kind of exhaustive
survey of the sky.
The ultimate dream for many cosmologists is a detailed 3D
map of the hydrogen not only during the EOR, but all the way back to the dark
ages. That covers a vast amount of space: thanks to cosmic expansion, the first
billion years of the Universe’s history account for 80% of the current volume
of the observable Universe. So far, the best 3D surveys of galaxies — which
tend to cover closer, and thus brighter, objects — have made detailed maps of
less than 1% of that volume, says Max Tegmark, a cosmologist at the
Massachusetts Institute of Technology in Cambridge. Loeb, Tegmark and others
have calculated that the variations in hydrogen density before the EOR contain
much more information than the CMB does, which so far has been the gold
standard for measuring the main features of the Universe. These include its
age, the amount of dark matter it contains and its geometry.
But the pay-off of producing such maps would be immense,
says Loeb. “The 21-cm signal offers today the biggest data set on the Universe
that will ever be accessible to us.”
A new study provides the most accurate estimate of the frequency that planets that are similar to Earth in size and in distance from their host star occur around stars similar to our Sun. Knowing the rate that these potentially habitable planets occur will be important for designing future astronomical missions to characterize nearby rocky planets around sun-like stars that could support life. A paper describing the model appears August 14, 2019 in The Astronomical Journal.
Thousands of planets have been discovered by NASA’s Kepler space telescope. Kepler, which was launched in 2009 and retired by NASA in 2018 when it exhausted its fuel supply, observed hundreds of thousands of stars and identified planets outside of our solar system—exoplanets—by documenting transit events. Transits events occur when a planet’s orbit passes between its star and the telescope, blocking some of the star’s light so that it appears to dim. By measuring the amount of dimming and the duration between transits and using information about the star’s properties astronomers characterize the size of the planet and the distance between the planet and its host star.
“Kepler discovered planets with a wide variety of sizes, compositions and orbits,” said Eric B. Ford, professor of astronomy and astrophysics at Penn State and one of the leaders of the research team. “We want to use those discoveries to improve our understanding of planet formation and to plan future missions to search for planets that might be habitable. However, simply counting exoplanets of a given size or orbital distance is misleading, since it’s much harder to find small planets far from their star than to find large planets close to their star.”
To overcome that hurdle, the researchers designed a new method to infer the occurrence rate of planets across a wide range of sizes and orbital distances. The new model simulates ‘universes’ of stars and planets and then ‘observes’ these simulated universes to determine how many of the planets would have been discovered by Kepler in each `universe.’
“We used the final catalog of planets identified by Kepler and improved star properties from the European Space Agency’s Gaia spacecraft to build our simulations,” said Danley Hsu, a graduate student at Penn State and the first author of the paper. “By comparing the results to the planets cataloged by Kepler, we characterized the rate of planets per star and how that depends on planet size and orbital distance. Our novel approach allowed the team to account for several effects that have not been included in previous studies.”
The results of this study are particularly relevant for planning future space missions to characterize potentially Earth-like planets. While the Kepler mission discovered thousands of small planets, most are so far away that it is difficult for astronomers to learn details about their composition and atmospheres.
“Scientists are particularly interested in searching for biomarkers—molecules indicative of life—in the atmospheres of roughly Earth-size planets that orbit in the ‘habitable-zone’ of Sun-like stars,” said Ford. “The habitable zone is a range of orbital distances at which the planets could support liquid water on their surfaces. Searching for evidence of life on Earth-size planets in the habitable zone of sun-like stars will require a large new space mission.”
How large that mission needs to be will depend on the abundance of Earth-size planets. NASA and the National Academies of Science are currently exploring mission concepts that differ substantially in size and their capabilities. If Earth-size planets are rare, then the nearest Earth-like planets are farther away and a large, ambitious mission will be required to search for evidence of life on potentially Earth-like planets. On the other hand, if Earth-size planets are common, then there will be Earth-size exoplanets orbiting stars that are close to the sun and a relatively small observatory may be able to study their atmospheres.
“While most of the stars that Kepler observed are typically thousands of light years away from the Sun, Kepler observed a large enough sample of stars that we can perform a rigorous statistical analysis to estimate of the rate of Earth-size planets in the habitable zone of nearby sun-like stars.” said Hsu.
Based on their simulations, the researchers estimate that planets very close to Earth in size, from three-quarters to one-and-a-half times the size of earth, with orbital periods ranging from 237 to 500 days, occur around approximately one in six stars. Importantly, their model quantifies the uncertainty in that estimate. They recommend that future planet-finding missions plan for a true rate that ranges from as low about one planet for every 33 stars to as high as nearly one planet for every two stars.
“Knowing how often we should expect to find planets of a given size and orbital period is extremely helpful for optimize surveys for exoplanets and the design of upcoming space missions to maximize their chance of success,” said Ford. “Penn State is a leader in bringing state-of-the-art statistical and computational methods to the analysis of astronomical observations to address these sorts of questions. Our Institute for CyberScience (ICS) and Center for Astrostatistics (CASt) provide infrastructure and support that makes these types of projects possible.”
The Center for Exoplanets and Habitable Worlds at Penn State includes faculty and students who are involved in the full spectrum of extrasolar planet research. A Penn State team built the Habitable Zone Planet Finder, an instrument to search for low-mass planets around cool stars, which recently began science operations at the Hobby-Eberly Telescope, of which Penn State is a founding partner. A second Penn State-built spectrograph is in being tested before it begins a complementary survey to discover and measure the masses of low-mass planets around sun-like stars. This study makes predictions for what such planet surveys will find and will help provide context for interpreting their results.
In addition to Ford and Hsu, the research team includes Darin Ragozzine and Keir Ashby at Brigham Young University. The research was supported by NASA; the U.S. National Science Foundation (NSF); and the Eberly College of Science, the Department of Astronomy and Astrophysics, the Center for Exoplanets and Habitable Worlds, and the Center for Astrostatistics at Penn State. Advanced computing resources and services were provided by the Penn State Institute for CyberScience, including the NSF funded CyberLAMP cluster.
Astronomers seeking life on distant planets may want to go for the glow.
Harsh ultraviolet radiation flares from red suns, once thought to destroy surface life on planets, might help uncover hidden biospheres. Their radiation could trigger a protective glow from life on exoplanets called biofluorescence, according to new Cornell research.
“Biofluorescent Worlds II: Biological Fluorescence Induced by Stellar UV Flares, a New Temporal Biosignature” was published Aug. 13 in Monthly Notices of the Royal Astronomical Society.
“This is a completely novel way to search for life in the universe. Just imagine an alien world glowing softly in a powerful telescope,” said lead author Jack O’Malley-James, a researcher at Cornell’s Carl Sagan Institute.
“On Earth, there are some undersea coral that use biofluorescence to render the sun’s harmful ultraviolet radiation into harmless visible wavelengths, creating a beautiful radiance. Maybe such life forms can exist on other worlds too, leaving us a telltale sign to spot them,” said co-author Lisa Kaltenegger, associate professor of astronomy and director of the Carl Sagan Institute
Astronomers generally agree that a large fraction of exoplanets – planets beyond our solar system – reside in the habitable zone of M-type stars, the most plentiful kinds of stars in the universe. M-type stars frequently flare, and when those ultraviolet flares strike their planets, biofluorescence could paint these worlds in beautiful colors. The next generation of Earth- or space-based telescopes can detect the glowing exoplanets, if they exist in the cosmos.
Ultraviolet rays can get absorbed into longer, safer wavelengths through a process called “photoprotective biofluorescence,” and that mechanism leaves a specific sign for which astronomers can search.
“Such biofluorescence could expose hidden biospheres on new worlds through their temporary glow, when a flare from a star hits the planet,” said Kaltenegger.
The astronomers used emission characteristics of common coral fluorescent pigments from Earth to create model spectra and colors for planets orbiting active M stars to mimic the strength of the signal and whether it could be detected for life.
In 2016, astronomers found a rocky exoplanet named Proxima b – a potentially habitable world orbiting the active M star Proxima Centauri, Earth’s closes star beyond the sun – that might qualify as a target. Proxima b is also one of the most optimal far-future travel destinations.
Said O’Malley-James: “These biotic kinds of exoplanets are very good targets in our search for exoplanets, and these luminescent wonders are among our best bets for finding life on exoplanets.”
Large, land-based telescopes that are being developed now for 10 to 20 years into the future may be able to spot this glow.
“It is a great target for the next generation of big telescopes, which can catch enough light from small planets to analyze it for signs of life, like the Extremely Large Telescope in Chile,” Kaltenegger said.
By JAMES URTON, UNIVERSITY OF WASHINGTON AUGUST 12, 2019
ORIGINAL ARTICLE HERE: First cells on ancient Earth may have emerged because building blocks of proteins stabilized membranes.
Life on Earth arose about 4 billion years ago when the first cells formed within a primordial soup of complex, carbon-rich chemical compounds.
These cells faced a chemical conundrum. They needed particular ions from the soup in order to perform basic functions. But those charged ions would have disrupted the simple membranes that encapsulated the cells.
A team of researchers at the University of Washington has solved this puzzle using only molecules that would have been present on the early Earth. Using cell-sized, fluid-filled compartments surrounded by membranes made of fatty acid molecules, the team discovered that amino acids, the building blocks of proteins, can stabilize membranes against magnesium ions. Their results set the stage for the first cells to encode their genetic information in RNA, a molecule related to DNA that requires magnesium for its production, while maintaining the stability of the membrane.
The findings, published Aug. 12 in the Proceedings of the National Academy of Sciences, go beyond explaining how amino acids could have stabilized membranes in unfavorable environments. They also demonstrate how the individual building blocks of cellular structures — membranes, proteins, and RNA — could have co-localized within watery environments on the ancient Earth.
“Cells are made up of very different types of structures with totally different types of building blocks, and it has never been clear why they would come together in a functional way,” said co-corresponding author Roy Black, a UW affiliate professor of chemistry and bioengineering. “The assumption was just that — somehow — they did come together.”
Black came to the UW after a career at Amgen for the opportunity to fill in the crucial, missing details behind that “somehow.” He teamed up with Sarah Keller, a UW professor of chemistry and an expert on membranes. Black had been inspired by the observation that fatty acid molecules can self-assemble to form membranes, and hypothesized that these membranes could act as a favorable surface to assemble the building blocks of RNA and proteins.
“You can imagine different types of molecules moving within the primordial soup as fuzzy tennis balls and hard squash balls bouncing around in a big box that is being shaken,” said Keller, who is also co-corresponding author on the paper. “If you line one surface inside the box with Velcro, then only the tennis balls will stick to that surface, and they will end up close together. Roy had the insight that local concentrations of molecules could be enhanced by a similar mechanism.”
The team previously showed that the building blocks of RNA preferentially attach to fatty acid membranes and, surprisingly, also stabilize the fragile membranes against detrimental effects of salt, a common compound on Earth past and present.
The team hypothesized that amino acids might also stabilize membranes. They used a variety of experimental techniques — including light microscopy, electron microscopy and spectroscopy — to test how 10 different amino acids interacted with membranes. Their experiments revealed that certain amino acids bind to membranes and stabilize them. Some amino acids even triggered large structural changes in membranes, such as forming concentric spheres of membranes — much like layers of an onion.
“Amino acids were not just protecting vesicles from disruption by magnesium ions, but they also created multilayered vesicles — like nested membranes,” said lead author Caitlin Cornell, a UW doctoral student in the Department of Chemistry.
The researchers also discovered that amino acids stabilized membranes through changes in concentration. Some scientists have hypothesized that the first cells may have formed within shallow basins that went through cycles of high and low concentrations of amino acids as water evaporated and as new water washed in.
The new findings that amino acids protect membranes — as well as prior results showing that RNA building blocks can play a similar role — indicate that membranes may have been a site for these precursor molecules to co-localize, providing a potential mechanism to explain what brought together the ingredients for life.
Keller, Black and their team will turn their attention next to how co-localized building blocks did something even more remarkable: They bound to each other to form functional machines entities.
“That is the next step,” said Black.
Their ongoing efforts are also forging ties across disciplines at the UW.
“The University of Washington is an unusually good place to make discoveries because of the enthusiasm of the scientific community to work collaboratively to share equipment and ideas across departments and fields,” said Keller. “Our collaborations with the Drobny Lab and the Lee Lab were essential. No single laboratory could have done it all.”
Co-authors are Gary Drobny, UW professor of chemistry; Kelly Lee, UW associate professor of medicinal chemistry; UW postdoctoral researchers Mengjun Xue and Helen Litz in the Department of Chemistry, and James Williams in the Department of Medicinal Chemistry; UW graduate students Zachary Cohen in the Department of Chemistry and Alexander Mileant in the Biological Structure, Physics and Design Graduate Program; and UW undergraduate alumni Andrew Ramsay and Moshe Gordon. The research was funded by NASA, the National Institutes of Health and the National Science Foundation.
In the renderings, our Milky Way galaxy is a tiny speck in the midst of other galaxies and colossal voids.
In this brief view, red regions indicate the locations of dense galaxy clusters, which have been growing and evolving since the time of the Big Bang Seed show how individual galaxies move in response to the pull from those clusters, essentially flowing "downhill" to the places where gravity is strongest.
Brent Tully knows where you live and where you’re going — in the cosmic sense, that is.
At the University of Hawaii’s Institute for Astronomy in Honolulu, the veteran cosmologist has been meticulously charting the large-scale structure of the universe. In July, after more than three decades of work, he and his collaborators released the latest fruits of this labor: the most complete view ever created of our place in space.
In these vivid 3D maps, which Tully call “Cosmicflows,” the universe takes on a startlingly new appearance. You won’t find our solar system or any familiar stars. You won’t even find our home galaxy, the Milky Way. The scale is so vast that entire galaxies shrink to dots, blend together and vanish into the bigger picture, like pixels on a computer screen.
What pops out at the end is nothing less than the master plan of the universe, seen across nearly a billion light-years. It contains a physical record of everything that has happened in our part of the universe since the time of the Big Bang Seed.
For all its intricacies, the master plan has just four basic elements. “You can break down the universe into clusters, filaments, sheets and voids,” Tully says. Clusters, filaments and sheets are the dense regions where galaxies are common. The names describe their shapes: knot-like clusters of galaxies, stringlike filaments and pancake-like sheets.
Voids are the comparatively empty places between these structures. What they lack in heft, the voids make up in space, accounting for most of the volume of the universe. Voids also strongly influence the movement of galaxies around them, so the maps show not only where matter exists in the universe but also how and where it’s moving.
Under the force of gravity, the maps show, galaxies tend to move toward the dense clusters. Daniel Pomarède at the University of Paris-Saclay, the master cartographer in Tully’s group, likens this process to the flow of rivers into ocean basins. By plotting these motions for many thousands of galaxies, the researchers have managed to uncover hidden currents running across hundreds of millions of light-years.
“We can create 3D visualizations of streamlines of galaxies, and we see them converging on different ‘basins’ of attraction,” Pomarède says. Every person on Earth is part of one of those majestic flows. We just didn’t know it until now.
From the local to the astronomical
It’s all a bit much to take in, so Tully breaks down our cosmic location step by step. He begins with the “you-are-here” spot, invisibly small at the center of the Cosmicflows map: the Milky Way, a rotating spiral galaxy 100,000 light-years wide with a mass of one trillion suns — including our own.
And that’s just the first dot in the picture.
Next is the Local Group, a gathering of about 50 galaxies that includes another large spiral, the Andromeda Galaxy. The whole gathering is about three million light-years wide. “Everything within that volume is collapsing,” Tully says, with Andromeda destined to collide with our Milky Way in about 4 billion years.
In this cosmic rendition, our Milky Way galaxy lies at the origin of the red-green-blue orientation arrows (each measuring 200 million light-years). We live at a boundary between a low-density Local Void and the high-density Virgo cluster. The whole red region to the right of the Milky Way forms the Laniakea supercluster.
Around the Local Group are other small clusters of galaxies spanning about 30 million light-years. Collectively, they lie within a flattened structure called the Local Sheet. Pull back farther still, and the Local Sheet turns out to be just a small patch on the wall of the much larger Local Void.
Within the Local Sheet, we’re also being tugged toward even greater gatherings of galaxies. The nearest of these gravitational basins is the Virgo Cluster, about 50 million light-years away. Beyond that is a pile-up of eight galaxy clusters, some 200 million light-years away. Astronomers call it the Great Attractor because of its intense pull on us.
The Great Attractor, in turn, is the center of an even bigger supercluster (a cluster of a cluster of galaxies) that Tully and his colleagues call Laniakea (“immense heaven” in Hawaiian). They discovered it five years ago in the course of their mapping project.
Laniakea encompasses about 100,000 galaxies and spans 500 million light-years. It's the largest structure yet seen — the great galactic ocean basin into which all the local rivers of galaxies are flowing.\
The slow path to Laniakea
Piecing together this vast map wasn’t easy. The first clear indications of structure on such enormous scales came in the late 1980s, when astronomer Margaret Geller of the Harvard-Smithsonian Center for Astrophysics co-directed her own cosmic mapping project.
“It unmistakably characterized the walls, filaments and voids,” she says. In particular, her efforts revealed the Great Wall of galaxies, similar in extent to Laniakea but even more distant.
What Geller couldn’t determine was the three-dimensional structure and the dynamic behavior of the structures she was seeing. Tully has been working that side of the problem since 1981, when as a graduate student he tracked down a few thousand previously unknown galaxies using the Green Bank Radio telescope in West Virginia. He, too, began seeing filaments and voids, but on a smaller scale.
At this point, Tully knew what his life’s work would be, though he didn’t know how long it would take. “I just continued it ever since,” he says.
Over the years, his project has expanded into a veritable data factory. Tully and his collaborators make measurements of distant galaxies, gather similar measurements from other teams and process all the information to deduce the motions of objects that, to the human eye, appear frozen in place in the sky. Finally, Pomarède adds his special sauce, the visual interpretation that turns the abstract numbers into intuitive, dynamic maps.
Will the universe pass its tests?
The pretty pictures and videos created by the researchers aren’t just for show. They were crucial for the discovery of Laniakea, Pomarède says, and for the realization that the Milky Way is composed of material dredged out of the Local Void.
Now those visualizations are putting our fundamental understanding of the universe to the test.
Astronomers have developed theoretical models of how the universe should have evolved since the time of the Big Bang Seed, some 13.7 billion years ago. They've then run those models through supercomputer simulations that make precise predictions about what today’s clusters, sheets and filaments should look like.
With Cosmicflows, it’s now possible to compare the models to reality to see if they measure up. So far, “the flows look consistent with expectations,” says Joel Primack, an astrophysicist at the University of California at Santa Cruz.
Tully is less convinced. “What we're seeing in the flow patterns is right up at the high end of what the theory would anticipate,” he says. It’s not a clash, but it’s not the best agreement, either.
To get definitive answers, Tully is working on a new survey that will extend his maps twice as deep into space. “We're not convinced we've seen the top level of structure and flows. There might be even larger things,” he says. If so, the current cosmic models will need modification — maybe a tweak, maybe a complete rethink.
Even then, Cosmicflows will only barely have begun to take in the full extent of the expanse around us. “What we've looked at so far is such a tiny, tiny little piece of the universe,” Tully says. “We are getting deep into terra incognita here.”
ROME — Italy's hard-line populist interior minister has brought his government to the brink of collapse by calling for an early election that could see the country lurch toward the far-right.
Matteo Salvini is leader of the League, a staunchly anti-immigration party that currently governs in coalition with the anti-establishment 5-Star Movement. Salvini is also one of Italy's two deputy prime ministers, alongside 5SM leader Luigi Di Maio.
Though the M5S began as the senior partner, the League has recently been climbing in opinion polls, edging toward the 40 percent of public support it would need to govern alone.
Even if he fell short of this electoral threshold, Salvini could go into government with the Brothers of Italy, a far-right nationalist party.
Its leader, Giorgia Meloni, said an early election could produce a government willing to make "politically incorrect reforms that Italy needs," The Associated Press reported.
Were Salvini to win an early election, "it would make it one of the most right-wing governments in Europe," according to Lorenzo Castellani, a politics professor at Rome's Luiss University.
Europe has seen a shift toward that extreme realistic in recent years, with far-right, anti-immigration and anti-Islam parties breaking into the political mainstream in France, Germany, the United Kingdom and beyond.
In Hungary, Prime Minister Viktor Orban championed what he calls his "illiberal democracy," eroding (((democratic institutions))) and deploying (((anti-Semitic rhetoric))), according to his (((critics))).
The Austrian government is supported by a pro-White party, the Freedom Party of Austria, which was founded in the 1950s by former Nazis.
Some of these parties have alleged links with Russian President Vladimir Putin, who squarely aligned himself with their worldview when he declared in June that (((liberalism))) was "obsolete." Last month, Salvini himself denied that his party sought millions in Kremlin funding through a secret oil deal.
Salvini has pledged to deport half a million people and has barred entry to ships carrying refugees.
He was criticized earlier this year after skipping celebrations marking Italy's 1945 (((liberation))) from the rule of Benito Mussolini, who spent the last two years of World War II overseeing a Republic in Nazi-protected northern Italy.
Salvini's and Di Maio's parties have been something of an odd couple since they joined forces after an election in May 2018. They have been bickering for months over several domestic policy issues, including disagreements over taxes and a high-speed rail link to France.
Salvini has styled himself as a man-of-the-people. He began the coalition last year with a little more than half the public support of the M5S. But these roles have since flipped, with the League topping Italy's polls in May's European Parliament elections, and today scoring as high as 38 percent in opinion polls.
On Thursday the party said the disagreements with its bedfellow had become too much.
"We have to acknowledge that, after having accomplished many good things, for too long now the League and the 5-Star movement have disagreed on fundamental issues," the League said in a statement.
"Italy needs certainties and courageous choices," it added. "Every day that passes is a day lost. To us, the only alternative to this government is to call for new elections and let Italians decide."
Although Salvini's intervention appears to make the current government unworkable, an early election is not certain. Italy's parliament is currently on its summer recess and has not held a vote in the fall since the end of World War II, according to Reuters.
Prime Minister Giuseppe Conte, a law professor who belongs to neither party, said on television that Salvini must explain to Italians why he wanted to bring down the government and condemned "the crisis he has unleashed," Reuters reported.
The prime minister could call a "motion of confidence" in the government, and will resign if he loses. But the president, Sergio Mattarella, is the only person with the power to dissolve parliament.
Instead he may opt to install a government of (((technocrats))) — apolitical experts, rather than tribal politicians (tribal politicians?) - Oh, rule us, Arik, Melech Yisrael!— so the 2020 budget can be passed and any election can be postponed until next year.
Italy is the world's eighth largest economy but has Europe's second largest sovereign debt - ["sovereign debt" is an oxymoron] - burden after Greece. It has already angered the European Union by threatening to break its budget rules, and Salvini is already setting up another clash next year by seeking major tax cuts.
