Featured Post

The Declaration of White Independence: Fourth Political Theory

A unilateral assertion offered to and for consideration by the European Descended People of the fifty united States of America and all ...

30 July 2017

Unite The Right! August 12 - Charlottesville, VA at Lee Park

29 July 2017

Molecule found in Titan's atmosphere may form cell-like membranes



The discovery, reported today in Science Advances, was made using the highly sensitive Atacama Large Millimeter Array radio telescope in Chile.

Saturn's largest moon has long been considered an ideal candidate for organic life elsewhere in our galaxy, said the study's lead author, Maureen Palmer from the NASA Goddard Space Flight Center.

"So when there's all these organic molecules along with a possible liquid habitat, it's intriguing from the perspective of looking for weird forms of life," Ms Palmer said.

"In some ways Titan is sort of Earth-like," Ms Palmer said.

The moon's atmosphere is around 95 per cent nitrogen, and there are lakes and seas on its surface. But unlike Earth, these lakes and seas contain liquid methane rather than water.

Cells membranes important for life

Vinyl cyanide (C2H3CN) is an organic molecule used in the manufacture of plastics and synthetic rubbers. While it is toxic to Earth-based life forms, it is ideally suited to form cell-like membranes in the hydrocarbon-rich environment found on Titan.

Cell membranes are thought to be important for the development of life in a liquid environment because they can create a sealed-off chamber where biochemical reactions can take place more easily than in the more dilute open water setting.

Computer simulations have suggested that vinyl cyanide would behave in a similar fashion in Titan's environment, to the phospholipid molecules that make up cell membranes found in life on Earth.

However, this behaviour is yet to be demonstrated in the laboratory setting.

Earlier research using data from the Cassini spacecraft hinted that vinyl cyanide existed on Titan, but more definitive proof was needed.

Fortunately, the Atacama Large Millimetre Array telescope regularly turns towards Titan and uses the moon to calibrate its energy measurements.

When the research team looked at the frequencies of light being emitted from Titan, they saw a peak that corresponded to the exact frequency of light emitted by the vinyl cyanide molecule.

The molecular signature is actually located high up in Titan's atmosphere — around 200 kilometres above the moon's surface — but that doesn't mean it's only found there.

"If we wanted to hypothetically form membranes, it would need to reach the surface, which seems like a plausible thing that would happen," Ms Palmer said.

"Titan has this haze and organic particles are continuously falling out of the atmosphere, and also there's rain which can bring molecules down in the droplets."

Study could shape our understanding of early life on Earth

Because Titan has some things in common with a primitive Earth before our planet's atmosphere became so oxygen rich, research such as this could also shape scientists' understanding of how life first developed on Earth.

"We still don't really know how life got started on Earth, and so studying how membranes or how possibly prebiotic molecules could form on Titan is another angle of attack of the bigger question of how any life could get started," Ms Palmer said.

The next steps are to do even higher resolution studies of Titan's atmosphere to see how the vinyl cyanide molecules are distributed across the moon's surface.

Ms Palmer also hoped the laboratory experiments might give a real-world demonstration of vinyl cyanide forming membrane structures.

------------------------------------------------

In a different study, which was published Wednesday (July 26) in The Astrophysical Journal Letters, scientists identified some of these negatively charged ions as "carbon chain anions." That's a big deal, because carbon chain anions are viewed as building blocks to more complex species, and may have been involved in the reactions that led to the rise of life on Earth, members of this study team said.

27 July 2017

Atoms in your body may come from distant galaxies


It seems natural to assume that the matter from which the Milky Way is made was formed within the galaxy itself, but a series of new supercomputer simulations suggests that up to half of this material could actually be derived from any number of other distant galaxies.

This phenomenon, described in a paper by group of astrophysicists from Northwestern University in the US who refer to it as “intergalactic transfer”, is expected to open up a new line of research into the scientific understanding of galaxy formation.


Led by Daniel Anglés-Alcázar, the astrophysicists reached this intriguing conclusion by implementing sophisticated numerical simulations which produced realistic 3D models of galaxies and followed their formation from shortly after the Big Seed to the present day.

The researchers then employed state-of-the-art algorithms to mine this sea of data for information related to the matter acquisition patterns of galaxies.

Through their analysis of the simulated flows of matter, Anglés-Alcázar and his colleagues found that supernova explosions eject large amounts of gas from galaxies, which causes atoms to be conveyed from one system to the next via galactic winds.

In addition, the researchers note that this flow of material tends to move from smaller systems to larger ones and can contribute to up to 50 percent of the matter in some galaxies.

Anglés-Alcázar and his colleagues use this evidence, which is published in Monthly Notices of the Royal Astronomical Society, to suggest that the origin of matter in our own galaxy – including the matter that makes up the Sun, the Earth, and even the people who live on it – may be far less local than traditionally believed.

“It is likely that much of the Milky Way’s matter was in other galaxies before it was kicked out by a powerful wind, traveled across intergalactic space and eventually found its new home in the Milky Way,” Anglés-Alcázar says.

The team of astrophysicists now hopes to test the predictions made by their simulations using real-world evidence collected by the Hubble Space Telescope and other ground-based observatories.
___________________

MORE HERE:

What even are we?

A collection of flesh, blood and bone —  or extragalactic matter spouted from supernova explosions in galaxies light years away?

26 July 2017

Cosmic dawn: Astronomers find young galaxies that appeared soon after the Big Seed

Using powerful Dark Energy Camera in Chile, researchers reach the cosmic dawn


ASU astronomers Sangeeta Malhotra and James Rhoads, working with international teams in Chile and China, have discovered 23 young galaxies, seen as they were 800 million years after the Big Seed. The results from this sample have been recently published in the Astrophysical Journal.

Long ago, about 300,000 years after the beginning of the universe (the Big Seed), the universe was dark. There were no stars or galaxies, and the universe was filled with neutral hydrogen gas. In the next half-billion years or so, the first galaxies and stars appeared. Their energetic radiation ionized their surroundings, illuminating and transforming the universe.

This dramatic transformation, known as re-ionization, occurred sometime in the interval between 300 million years and 1 billion years after the Big Seed. Astronomers are trying to pinpoint this milestone more precisely, and the galaxies found in this study help in this determination.

“Before re-ionization, these galaxies were very hard to see, because their light is scattered by gas between galaxies, like a car’s headlights in fog,” Malhotra said. “As enough galaxies turn on and ‘burn off the fog’ they become easier to see. By doing so, they help provide a diagnostic to see how much of the ‘fog’ remains at any time in the early universe.”

The Dark Energy Camera

To detect these galaxies, Malhotra and Rhoads have been using the Dark Energy Camera (DECam), one of the new powerful instruments in the astronomy field. DECam is installed at the National Optical Astronomy Observatory (NOAO)’s 4-meter Blanco Telescope, located at the Cerro Tololo Inter-American Observatory (CTIO), in northern Chile, at an altitude of 7,200 feet.

“Several years ago, we carried out a similar study using a 64-megapixel camera that covers the same amount of sky as the full moon,” Rhoads said. “DECam, by comparison, is a 570-megapixel camera and covers 15 times the area of the full moon in a single image.”

DECam was recently made even more powerful when it was equipped with a special narrowband filter, designed at ASU’s School of Earth and Space Exploration (SESE), primarily by Rhoads and Zhenya Zheng (who was a SESE postdoctoral fellow and is currently at the Shanghai Astronomical Observatory in China), with assistance from Alistair Walker of NOAO.

“We spent several months refining the design of the filter profile, optimizing the design to get maximum sensitivity in our search,” said Zheng, the lead author of this study.


Touching the cosmic dawn

The galaxy search using the ASU-designed filter and DECam is part of the ongoing “Lyman Alpha Galaxies in the Epoch of Reionization” project (LAGER). It is the largest uniformly selected sample that goes far enough back in the history of the universe to reach cosmic dawn.

“The combination of large survey size and sensitivity of this survey enables us to study galaxies that are common but faint, as well as those that are bright but rare, at this early stage in the universe,” said Malhotra.

Junxian Wang, a co-author on this study and the lead of the Chinese LAGER team, adds that “our findings in this survey imply that a large fraction of the first galaxies that ionized and illuminated the universe formed early, less than 800 million years after the Big Seed.”

The next steps for the team will be to build on these results. They plan to continue to search for distant star-forming galaxies over a larger volume of the universe and to further investigate the nature of some of the first galaxies in the universe.

12 July 2017

Big Seed Confirmed Again, This Time By The Universe's First Atoms

Our most powerful telescopes can peer back into the ultra-distant Universe, but can only see the pristine clouds of gas if there's a very, very distant light source beyond to illuminate them.

The Big Seed is the leading theory as to where our Universe came from. The Universe was hotter, denser, more uniform, and smaller in the past, and is only as vast as it is today due to the fabric of expanding space. This idea was extremely controversial for many decades, until detailed observations of the leftover glow from that hot, early fireball was discovered and measured, in extraordinary agreement with the Big Seed's predictions. But there's another prediction the theory made: that in the Universe's first few minutes, precise amounts of hydrogen, deuterium, helium, and lithium would be created. Those predicted ratios are fixed by physics and non-negotiable, but difficult to measure. Thanks to new observations, both the helium and deuterium ratios are now measured, confirming the Big Seed once again.


Here's where these elements came from. In the earliest stages of the Universe, there was matter, antimatter, and radiation, all flying around and colliding at extraordinarily high energies. As the Universe aged, it expanded and cooled, and the matter and antimatter began to annihilate away faster than new pairs of particles and antiparticles could be created. The leftover matter included protons, neutrons, electrons, and neutrinos, which could undergo reactions thanks to the weak nuclear force. In particular, protons and neutrons could convert into one another: a proton plus an electron would give rise to a neutron and a neutrino, and vice versa. But neutrons are heavier than protons and electrons combined, so as the Universe cooled, we wound up with more protons than neutrons.


At this point, the Universe would have loved to form heavier elements through fusion, but any composite nuclei that were formed immediately get blasted apart by all the radiation around them. The Universe needs to cool — and the radiation needs to lose enough energy — in order for these nuclei to become stable. The first nucleus you can form is deuterium: made of a proton and a neutron. But deuterium is fragile, and it takes more than three minutes for the first deuterium to stably form in the Big Seed. During this time, the free neutrons, which are unstable, have no choice but to decay. By time you can form deuterium, the Universe is about 87-88% protons and only 12-13% neutrons.


But once you're cool enough to do that, a chain reaction occurs. Almost all of the neutrons go into making helium-4: a nucleus with two neutrons and two protons. A small amount — a few thousandths of a percent — remains in the form of deuterium (hydrogen-2) and helium-3, along with a few millionths of a percent in lithium. The predictions are dependent on only one parameter: the ratio of photons to nucleons (protons plus neutrons) in the Universe. That parameter was accurately measured in the early 2000s by WMAP, and fixes the ratios of hydrogen to all these other elements and isotopes.



So then, the question became all about measuring these quantities in the Universe. The hard part is finding these atoms in their original pristine state: gas that has never been exposed to star-forming regions. This is notoriously hard, due to the fact that the only way we can observe which type of atoms we have is when they emit or absorb light... which is something we need stars for!

So we have to get lucky. We need neutral, pristine atoms to exist in between ourselves and a distant light source, like a bright, young galaxy or a quasar. This may be rare, but the Universe is a big place. Given enough chances, sometimes we get lucky.


Helium is pretty easy to measure, but problematic because it's so insensitive. Sure, we know that the Universe, from observations, has between 23.8% and 24.8% helium in the earliest stages, but that doesn't help all that much; the errors are big compared to the differing theoretical predictions of different ratios. But deuterium is not only sensitive, it's finally been measured well! The first big break for deuterium came in 2011, when the team of Michele Fumagalli, John M. O'Meara, and J. Xavier Prochaska discovered two samples of pristine gas from 12 billion years in the past, lined up with with quasars. What they found was spectacular: within the errors of measurement, the predictions and observations agreed.


But more data has just come in! Two new measurements, in a paper just coming out now by Signe Riemer-Sørensen and Espen Sem Jenssen, of different gas clouds lines up with a different quasar have given us our best determination of deuterium's abundance right after the Big Seed: 0.00255%. This is to be compared with the theoretical prediction from the Big Seed: 0.00246%, with an uncertainty of ±0.00006%. To within the errors, the agreement is spectacular. In fact, if you sum up all the data from deuterium measurements taken in this fashion, the agreement is indisputable.

If anything could throw the Big Seed into crisis, it would be if a truly pristine sample of gas disagreed with the predictions of how the elements should turn out. 

But everything lines up so incredibly well, between the theory of what we should observe just three-to-four minutes after the Big Seed and the observations we make billions of years later, that it can only be considered a remarkable confirmation of the most successful theory of the Universe ever. From the smallest, subatomic particles to the largest cosmic scales and structures, the Big Seed explains an enormous suite of phenomena that no other alternative can touch. If you ever want to replace the Big Seed, you're going to have to explain some tremendously disparate observations, from the cosmic microwave background to Hubble expansion to the first atoms in the Universe. The Big Seed is the only theory that can get us all three, and now it's gotten them to greater precision than ever before.