Space isn't remote at all. It's only an hour's drive away if your car could go upwards.

— Fred Hoyle

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Many Labrador Retriever Dogs Really Are Hungry All the Time—It’s in Their Genes

Scientific American.com - Wed, 03/06/2024 - 3:00pm

One in four Labrador retrievers carries a gene that tricks their brain into thinking they’re starving

Categories: Astronomy

Webb Sees a System That Just Finished Forming its Planets

Universe Today - Wed, 03/06/2024 - 2:54pm

Nearly 5 billion years ago a region of gas gravitationally collapsed within a vast molecular cloud. At the center of the region, the Sun began to form, while around it formed a protoplanetary disk of gas and dust out of which Earth and the other planets of the solar system would form. We know this is how the solar system began because we have observed this process in systems throughout the galaxy. But there are details of the process we still don’t understand, such as why gas planets are relatively rare in our system.

Our solar system only has four gas planets. The rest are the rocky worlds of the inner solar system. Then there are countless asteroids and the icy worlds of Pluto and the outer solar system. Most of them don’t contain a lot of volatile gasses, which is strange because early protoplanetary disks typically have a hundred times more gas than dust. So how does a gassy disk evolve into a planetary system of mostly rock? The answer can be found in recent observations of a young system known as TCha.

The general idea is that during the later stage of planetary formation the central star increases in brightness. The light from the star then drives winds within the disk which clears any remaining gas from the system. While this model can explain the type of planetary systems we observe, the process hasn’t been observed directly. That is, until this recent study.

How photon pressure can clear a planetary system of gas. Credit: Naman S. Bajaj, et al

TCha is a system in the late stages of planetary formation. Earlier observations found it has a large dust gap within the disk with a radius of more than 30 AU, indicating that much of the early material has already cleared. So in this new study, the team used observations from the James Webb Space Telescope (JWST) to measure the spectral lines of ionized argon and neon. This study is the first observation of a particular argon line, Ar III.

The team made two main discoveries. The first is based on the ionizing energy levels, which indicates that argon is mostly ionized by extreme ultraviolet light, while neon is mostly ionized by X-rays. The second is that both gases are rapidly expanding away from the star, as seen by the Doppler shift of the spectral lines. Together these discoveries show that the gases are part of a stellar wind driven by high-energy photons.

Based on the observations, the team estimates that the TCha disk is losing about a Moon’s worth of mass every year, which is fast enough to clear the planetary disks in agreement with observations of planetary systems. While there are many details of planetary evolution we still don’t understand, this study supports the standard model.

Reference: Naman S. Bajaj, et al. “JWST MIRI MRS Observations of T Cha: Discovery of a Spatially Resolved Disk Wind.” The Astronomical Journal 167 (2024): 127.

The post Webb Sees a System That Just Finished Forming its Planets appeared first on Universe Today.

Categories: Astronomy

How Heavy Is a Neutrino? Physicists Are Still Racing to Find Answers

Scientific American.com - Wed, 03/06/2024 - 2:45pm

A new generation of lab experiments is aiming to weigh neutrinos with astonishing accuracy

Categories: Astronomy

Webb Sees a Surprisingly Active Galaxy When the Universe Was Only 430 Million Years Old

Universe Today - Wed, 03/06/2024 - 2:32pm

Unlocking the mysteries of the early Universe is one of the JWST’s primary endeavours. Finding and examining some of the first galaxies is an important part of its work. One of the Universe’s first galaxies is extraordinarily luminous, and researchers have wondered why. It looks like the JWST has found the answer.

The galaxy at issue is named GN-z11, and it existed when the Universe was less than half a billion years old. The Hubble first spotted it in 2016, with help from the Spitzer Space Telescope. At the time, it was the most distant, ancient galaxy ever spotted. In the paper announcing the discovery, the authors wrote, “GN-z11 is luminous and young, yet moderately massive, implying a rapid build-up of stellar mass in the past.”

They also wrote that “Future facilities will be able to find the progenitors of such galaxies at higher redshift and probe the cosmic epoch at the beginning of reionization.” Now that the JWST is deep into its mission, that’s exactly where we find ourselves. It also took a closer look at GN-z11.

The discoverers suggested that the galaxy’s high luminosity could be caused by an active galactic nucleus (AGN) but weren’t certain. New research based on JWST observations shows that they were right. It looks like the galaxy’s luminosity comes from a supermassive black hole (SMBH) in the galaxy’s centre, lighting it up as it actively accretes matter. One of the telltale signs is a gas clump near the SMBH.

“We found extremely dense gas that is common in the vicinity of supermassive black holes accreting gas,” explained principal investigator Roberto Maiolino of the Cavendish Laboratory and the Kavli Institute of Cosmology at the University of Cambridge in the United Kingdom. “These were the first clear signatures that GN-z11 is hosting a black hole that is gobbling matter.”

Scientists know that the region near an SMBH is extremely hot and that gas clumps form near there. The hole’s powerful gravity creates a swirling accretion disk of material near it, and the material in the disk can be accelerated to relativistic speeds. At those speeds, the molecules collide and generate friction. That generates heat that can reach a temperature of millions of degrees. The extreme heat drives gas outward at extremely high speeds, but it can also drive the gas to form dense clumps like the ones JWST found at GN-z11.

The clump lacks metallicity, so it’s likely primordial in nature, uncontaminated by heavier elements that would only later be created by successive generations of stars.

This graphic shows a clump of pristine helium near GN-z11. The full spectrum shows no evidence of other elements and so suggests that the helium clump is fairly pristine, made almost entirely of hydrogen and helium gas left over from the Big Bang. It’s uncontaminated by heavier elements produced by stars. Theory and simulations in the vicinity of particularly massive galaxies from these epochs predict that there should be pockets of pristine gas surviving in the halo, and these may collapse and form Population III star clusters. Image Credit: NASA, ESA, CSA, Ralf Crawford (STScI) CC BY 4.0 INT

We’ve never seen the Universe’s first stars, the Population III stars. But as the very first stars, they formed from hydrogen and helium, all that was available at the time. Finding those first stars is an important goal in astronomy, so finding these similarly pristine clumps is important. The gas clumps found by JWST are also made only of hydrogen and helium, so they could be precursors to the formation of Population III stars.

“The fact that we don’t see anything else beyond helium suggests that this clump must be fairly pristine,” said Maiolino. “This is something that was expected by theory and simulations in the vicinity of particularly massive galaxies from these epochs – that there should be pockets of pristine gas surviving in the halo, and these may collapse and form Population III star clusters.”

Population III stars were the Universe’s first stars and contained only hydrogen and helium. They were extremely massive, luminous stars, and many of them exploded as supernovae. Image Credit: DALL-E

Two more pieces of evidence support the black hole hypothesis. Accreting black holes produce ionized chemical elements, and the JWST found evidence of them. The powerful space telescope also detected high winds with velocities of 800 to 1000 km/s-1 near the black hole, another result of the processes involved in actively accreting black holes. (Some rare starburst galaxies can also produce powerful winds, but they show less ionization.)

“Webb’s NIRCam (Near-Infrared Camera) has revealed an extended component, tracing the host galaxy, and a central, compact source whose colours are consistent with those of an accretion disc surrounding a black hole,” said investigator Hannah Übler, also of the Cavendish Laboratory and the Kavli Institute.

There doesn’t seem to be much doubt that GN-z11 has a black hole and its accretion disk in its center. But the fact that this galaxy’s extreme luminosity is powered by a black hole raises interesting questions. It has to do with black hole seeds and the Eddington rate.

Scientists think that black holes in the early Universe could have formed differently than stellar mass black holes, which form when a star collapses under its own gravity. Instead, these ancient black holes formed from seeds, collections of matter massive enough to collapse directly into black holes. There could be large, intermediate, and small black hole seeds. The researchers behind these results write that the black hole is “… accreting at about five times the Eddington rate. These properties are consistent with both heavy seeds scenarios and scenarios considering intermediate and light seeds experiencing episodic super-Eddington phases.”

The Eddington rate is the rate at which a black hole has to accrete matter to reach the Eddington limit. The Eddington limit is the maximum luminosity an object can reach while its outward force of radiation is equal to its inward force of gravity.

But black holes can exceed the Eddington limit during super-Eddington episodes. Those episodes may be able to explain the rapid assembly of supermassive black holes (SMBHs) in the Universe’s first billion years. Super-Eddington episodes are associated with radiatively inefficient accretion and are often accompanied by powerful outflowing winds and jets.

If the researchers are correct, then they’ve figured out the mystery behind this extremely ancient and extremely luminous galaxy. “Our finding explains the high luminosity of GN-z11…,” the authors write.

Note: The research on the pristine gas clump in GN-z11’s halo has been accepted for publication in Astronomy & Astrophysics. The results of the study of GN-z11’s black hole were published in the journal Nature on 17 January 2024

The post Webb Sees a Surprisingly Active Galaxy When the Universe Was Only 430 Million Years Old appeared first on Universe Today.

Categories: Astronomy

We should be open about organoid research to avoid a backlash

New Scientist Space - Space Headlines - Wed, 03/06/2024 - 2:00pm
Research that involves creating "mini-organs" from human cells, including those from fetuses, may leave people uncomfortable – so the best approach is to explain the reasoning behind the work and its potential benefits
Categories: Astronomy

We should be open about organoid research to avoid a backlash

New Scientist Space - Cosmology - Wed, 03/06/2024 - 2:00pm
Research that involves creating "mini-organs" from human cells, including those from fetuses, may leave people uncomfortable – so the best approach is to explain the reasoning behind the work and its potential benefits
Categories: Astronomy

The scientific secrets to baking a perfectly moist chocolate cake

New Scientist Space - Cosmology - Wed, 03/06/2024 - 2:00pm
Keeping your chocolate cake moist and delicious when you make it party-sized is tricky, but not impossible, says Catherine de Lange
Categories: Astronomy

The scientific secrets to baking a perfectly moist chocolate cake

New Scientist Space - Space Headlines - Wed, 03/06/2024 - 2:00pm
Keeping your chocolate cake moist and delicious when you make it party-sized is tricky, but not impossible, says Catherine de Lange
Categories: Astronomy

The Tomb of the Mili Mongga review: Hunting for giants in Indonesia

New Scientist Space - Space Headlines - Wed, 03/06/2024 - 2:00pm
Samuel Turvey set off for Indonesia in search of fossils and found all sorts of wonders – including the strange story of mythical wild men who just might be lurking on the island of Sumba
Categories: Astronomy

The Tomb of the Mili Mongga review: Hunting for giants in Indonesia

New Scientist Space - Cosmology - Wed, 03/06/2024 - 2:00pm
Samuel Turvey set off for Indonesia in search of fossils and found all sorts of wonders – including the strange story of mythical wild men who just might be lurking on the island of Sumba
Categories: Astronomy

Stark, haunting images show Kazakhstan's former nuclear testing ground

New Scientist Space - Cosmology - Wed, 03/06/2024 - 2:00pm
These stunning photographs are all shortlisted for the Sony World Photography Awards 2024
Categories: Astronomy

Stark, haunting images show Kazakhstan's former nuclear testing ground

New Scientist Space - Space Headlines - Wed, 03/06/2024 - 2:00pm
These stunning photographs are all shortlisted for the Sony World Photography Awards 2024
Categories: Astronomy

A tale of two mysteries: ghostly neutrinos and the proton decay puzzle

New Scientist Space - Cosmology - Wed, 03/06/2024 - 2:00pm
Searching for the true nature of neutrino particles also provides the perfect experimental conditions to seek evidence of another slippery customer – proton decay, says Chanda Prescod-Weinstein
Categories: Astronomy

Could two genetically modified mice come in handy on Valentine's Day?

New Scientist Space - Cosmology - Wed, 03/06/2024 - 2:00pm
Feedback is delighted to learn about a company's Valentine's Day promotion offering "a complimentary breeding pair of genetically modified mice" to potential customers in the mood for romance
Categories: Astronomy

How manners can be a weapon to divide and disempower

New Scientist Space - Cosmology - Wed, 03/06/2024 - 2:00pm
Living in close proximity to strangers requires shared social norms – but manners can also be used to divide us, says Kirsty Sedgman
Categories: Astronomy

A tale of two mysteries: ghostly neutrinos and the proton decay puzzle

New Scientist Space - Space Headlines - Wed, 03/06/2024 - 2:00pm
Searching for the true nature of neutrino particles also provides the perfect experimental conditions to seek evidence of another slippery customer – proton decay, says Chanda Prescod-Weinstein
Categories: Astronomy

Could two genetically modified mice come in handy on Valentine's Day?

New Scientist Space - Space Headlines - Wed, 03/06/2024 - 2:00pm
Feedback is delighted to learn about a company's Valentine's Day promotion offering "a complimentary breeding pair of genetically modified mice" to potential customers in the mood for romance
Categories: Astronomy

How manners can be a weapon to divide and disempower

New Scientist Space - Space Headlines - Wed, 03/06/2024 - 2:00pm
Living in close proximity to strangers requires shared social norms – but manners can also be used to divide us, says Kirsty Sedgman
Categories: Astronomy

The Story of Earth's Climate review: 25 discoveries tell tangled tale

New Scientist Space - Cosmology - Wed, 03/06/2024 - 2:00pm
Palaeontologist Donald R. Prothero squares up to the tough task of explaining how life and climate have shaped each other over the 4.5 billion years of Earth's history. Amazingly, his book mostly succeeds
Categories: Astronomy

The Story of Earth's Climate review: 25 discoveries tell tangled tale

New Scientist Space - Space Headlines - Wed, 03/06/2024 - 2:00pm
Palaeontologist Donald R. Prothero squares up to the tough task of explaining how life and climate have shaped each other over the 4.5 billion years of Earth's history. Amazingly, his book mostly succeeds
Categories: Astronomy