Institute of Astronomy

Astronomy News

Planets around graveyard star were consumed before Earth was even born

5 November 2022 - 8:34pm

A strangely cool star that has been dead for more than 10 billion years contains levels of some elements that indicate it ate its own planets

Hubble Inspects a Pair of Space Oddities

4 November 2022 - 8:13pm
Portal origin URL: Hubble Inspects a Pair of Space OdditiesPortal origin nid: 483771Published: Friday, November 4, 2022 - 08:00Featured (stick to top of list): noPortal text teaser: This image from the NASA/ESA Hubble Space Telescope shows two of the galaxies in the galactic triplet Arp 248 – also known as Wild's Triplet – which lies around 200 million light-years from Earth in the constellation Virgo.Portal image: Two face-on spiral galaxies at upper-left and lower-right corners. A long, faint, pale-blue streak joins them, crossing the field diagonally. A small, orange, edge-on spiral galaxy at left of the lower galaxy.

How NASA’s Roman Telescope Will Scan for Showstopping Explosions

4 November 2022 - 8:12pm
Portal origin URL: How NASA’s Roman Telescope Will Scan for Showstopping ExplosionsPortal origin nid: 483363Published: Thursday, November 3, 2022 - 10:00Featured (stick to top of list): noPortal text teaser: What happens when the densest, most massive stars – that are also super small – collide? They send out brilliant explosions known as kilonovae. Scientists will soon have an additional observatory to help follow up on and even scout these remarkable events: NASA’s Nancy Grace Roman Space Telescope, which is set to launch by May 2027.Portal image: Left of center, two bright blue circular shapes appear to be joined toward the center of the frame. They are whitest on their outermost edges. Debris, also white and bright blue, emanates outward and extends all around the frame. The background is black.

NASA’s IXPE Reveals Shape, Orientation of Hot Matter Around Black Hole

4 November 2022 - 8:12pm
Portal origin URL: NASA’s IXPE Reveals Shape, Orientation of Hot Matter Around Black HolePortal origin nid: 483772Published: Thursday, November 3, 2022 - 13:00Featured (stick to top of list): noPortal text teaser: Cygnus X-1, discovered in 1964, was the first cosmic object ever identified as containing a black hole. Now, NASA telescopes have teamed up to reveal new details about the configuration of hot matter surrounding this famous black hole.Portal image: This is an artists's impression. A large blue sphere is on the left with a yellow spiral of a black hold is in the middle of the photo.

Neutrinos have been spotted coming from a strange, shrouded galaxy

4 November 2022 - 8:11pm

Cosmic neutrinos are tough to track – it has only been done once before – but researchers from the IceCube observatory in Antarctica have tracked 79 of them back to their home galaxy

A weird dead star may have a solid-like surface made of iron crystals

4 November 2022 - 8:11pm

X-ray observations show that a distant magnetar may have a surface made of a strange material somewhere between a solid and a fluid instead of a gaseous one like most stars

Should Webb telescope’s data be open to all?

4 November 2022 - 8:09pm
Science, Volume 378, Issue 6619, Page 458-459, November 2022.

Neutrinos unveil hidden galactic activities

4 November 2022 - 8:08pm
Science, Volume 378, Issue 6619, Page 474-475, November 2022.

Evidence for neutrino emission from the nearby active galaxy NGC 1068

4 November 2022 - 8:08pm
Science, Volume 378, Issue 6619, Page 538-543, November 2022.

Can cosmic inflation be ruled out?

4 November 2022 - 7:58pm

The astrophysicists, from the University of Cambridge, the University of Trento, and Harvard University, say that there is a clear, unambiguous signal in the cosmos which could eliminate inflation as a possibility. Their paper, published in The Astrophysical Journal Letters, argues that this signal – known as the cosmic graviton background (CGB) – can feasibly be detected, although it will be a massive technical and scientific challenge.

“Inflation was theorised to explain various fine-tuning challenges of the so-called hot Big Bang model,” said the paper’s first author Dr Sunny Vagnozzi, from Cambridge’s Kavli Institute for Cosmology, and who is now based at the University of Trento. “It also explains the origin of structure in our Universe as a result of quantum fluctuations.

“However, the large flexibility displayed by possible models for cosmic inflation which span an unlimited landscape of cosmological outcomes raises concerns that cosmic inflation is not falsifiable, even if individual inflationary models can be ruled out. Is it possible in principle to test cosmic inflation in a model-independent way?”

Some scientists raised concerns about cosmic inflation in 2013, when the Planck satellite released its first measurements of the cosmic microwave background (CMB), the universe's oldest light.

“When the results from the Planck satellite were announced, they were held up as a confirmation of cosmic inflation,” said Professor Avi Loeb from Harvard University, Vagnozzi’s co-author on the current paper. “However, some of us argued that the results might be showing just the opposite.”

Along with Anna Ijjas and Paul Steinhardt, Loeb was one of those who argued that results from Planck showed that inflation posed more puzzles than it solved, and that it was time to consider new ideas about the beginnings of the universe, which, for instance, may have begun not with a bang but with a bounce from a previously contracting cosmos.

The maps of the CMB released by Planck represent the earliest time in the universe we can ‘see’, 100 million years before the first stars formed. We cannot see farther.

“The actual edge of the observable universe is at the distance that any signal could have travelled at the speed-of-light limit over the 13.8 billion years that elapsed since the birth of the Universe,” said Loeb. “As a result of the expansion of the universe, this edge is currently located 46.5 billion light years away. The spherical volume within this boundary is like an archaeological dig centred on us: the deeper we probe into it, the earlier is the layer of cosmic history that we uncover, all the way back to the Big Bang which represents our ultimate horizon. What lies beyond the horizon is unknown.”

In could be possible to dig even further into the universe’s beginnings by studying near-weightless particles known as neutrinos, which are the most abundant particles that have mass in the universe. The Universe allows neutrinos to travel freely without scattering from approximately a second after the Big Bang, when the temperature was ten billion degrees. “The present-day universe must be filled with relic neutrinos from that time,” said Vagnozzi.

Vagnozzi and Loeb say we can go even further back, however, by tracing gravitons, particles that mediate the force of gravity.

“The Universe was transparent to gravitons all the way back to the earliest instant traced by known physics, the Planck time: 10 to the power of -43 seconds, when the temperature was the highest conceivable: 10 to the power of 32 degrees,” said Loeb. “A proper understanding of what came before that requires a predictive theory of quantum gravity, which we do not possess.”

Vagnozzi and Loeb say that once the Universe allowed gravitons to travel freely without scattering, a relic background of thermal gravitational radiation with a temperature of slightly less than one degree above absolute zero should have been generated: the cosmic graviton background (CGB).

However, the Big Bang theory does not allow for the existence of the CGB, as it suggests that the exponential inflation of the newborn universe diluted relics such as the CGB to a point that they are undetectable. This can be turned into a test: if the CGB were detected, clearly this would rule out cosmic inflation, which does not allow for its existence.

Vagnozzi and Loeb argue that such a test is possible, and the CGB could in principle be detected in future. The CGB adds to the cosmic radiation budget, which otherwise includes microwave and neutrino backgrounds. It therefore affects the cosmic expansion rate of the early Universe at a level that is detectable by next-generation cosmological probes, which could provide the first indirect detection of the CGB.

However, to claim a definitive detection of the CGB, the ‘smoking gun’ would be the detection of a background of high-frequency gravitational waves peaking at frequencies around 100 GHz. This would be very hard to detect, and would require tremendous technological advances in gyrotron and superconducting magnets technology. Nevertheless, say the researchers, this signal may be within our reach in future.

Reference:
Sunny Vagnozzi and Abraham Loeb. ‘The Challenge of Ruling Out Inflation via the Primordial Graviton Background.’ The Astrophysical Journal Letters (2022). DOI: 10.3847/2041-8213/ac9b0e

Adapted in part from a piece on Medium by Avi Loeb.

Astrophysicists say that cosmic inflation – a point in the Universe’s infancy when space-time expanded exponentially, and what physicists really refer to when they talk about the ‘Big Bang’ – can in principle be ruled out in an assumption-free way.

Is it possible in principle to test cosmic inflation in a model-independent way?Sunny VagnozziA. Ijjas, P.J. Steinhardt and A. Loeb (Scientific American, February 2017)Cosmic inflation is a popular scenario for the earliest phase in the evolution of the Universe


The text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright ©University of Cambridge and licensors/contributors as identified.  All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

ALMA Services Affected by Cyberattack

3 November 2022 - 10:07am

Last Saturday, 29 October, at 6:14 AM (GMT-3), the ALMA observatory in Chile suffered a cyberattack on its computer systems, forcing the suspension of astronomical observations and the public website. There are limited email services at the observatory. The threat has been contained, and our specialists are working hard to restore affected systems. The attack did not compromise the ALMA antennas or any scientific data. Given the nature of the episode, it is not yet possible to estimate a timeline for a return to regular activities. We are thankful for the support and understanding across the ALMA partnership and apologize for any inconveniences resulting from the recovery efforts.

NASA's Chandra: Planets Can Be Anti-Aging Formula for Stars

3 November 2022 - 10:03am
Portal origin URL: NASA's Chandra: Planets Can Be Anti-Aging Formula for StarsPortal origin nid: 483736Published: Wednesday, November 2, 2022 - 10:00Featured (stick to top of list): noPortal text teaser: Planets can force their host stars to act younger than their age, according to a new study of multiple systems using NASA’s Chandra X-ray Observatory.Portal image: An artist’s illustration shows a gas giant planet as blue, brown, grey swirls in the lower right closely orbiting its host star on the left that is the a large orange and yellow semi circle, with another star in the distance (upper right).

Crooked star clusters may be a sign that Einstein’s gravity is wrong

2 November 2022 - 9:50am

Astronomers have found an unexpected asymmetry in stars escaping from their clusters, and it can't be easily explained by our standard theories of gravity

ESO captures the ghost of a giant star

1 November 2022 - 10:11am
A spooky spider web, magical dragons or wispy trails of ghosts? What do you see in this image of the Vela supernova remnant? This beautiful tapestry of colours shows the ghostly remains of a gigantic star, and was captured here in incredible detail with the VLT Survey Telescope, hosted at the European Southern Observatory’s (ESO’s) Paranal site in Chile.

Publisher Correction: A repeating fast radio burst associated with a persistent radio source

1 November 2022 - 10:11am

Nature, Published online: 31 October 2022; doi:10.1038/s41586-022-05456-9

Publisher Correction: A repeating fast radio burst associated with a persistent radio source

Cloudspotting on Mars Project Extended!

1 November 2022 - 10:11am

Clouds and a dust storm on Mars captured by the MARCI instrument on NASA’s Mars Reconnaissance Orbiter. How does dust influence cloud formation? (Credit: NASA/JPL-Caltech/Malin Space Science Systems)

The forecast for the Cloudspotting on Mars project is cloudy. And that’s a good thing! The Cloudspotting on Mars citizen science project has received additional funding from NASA’s Mars Data Analysis Program to search for clouds in more Mars data.  

So far, citizen scientists have been hard at work analyzing data from Mars Year 29 (Dec. 2007-Oct. 2009). Participants classified over 6000 images in just a few weeks—data from the Mars Climate Sounder (MCS) onboard Mars Reconnaissance Orbiter.  A Mars year corresponds to 687 Earth days. It’s longer than an Earth year because it takes Mars longer to orbit the Sun.

The extension lets us study data spanning two more Mars years. That’s important because every year on Mars is different. The latest data from Mars Year 30 (Oct. 2009-Sep. 2011) and Mars Year 31 (Sep. 2011-Jul. 2013) span a time when Mars was less dusty than in previous years. Your assistance with this data will help reveal how dust and different environmental conditions affect cloud formation.

Help find exotic clouds high in the Martian atmosphere! Become a Martian Cloudspotter today.

NASA’s Citizen Science Program:
Learn about NASA citizen science projects
Follow on Twitter
Follow on Facebook 

News Article Type: Homepage ArticlesPublished: Monday, October 31, 2022 - 09:44

JWST finds ancient galaxy may actually be two galaxies merging

1 November 2022 - 10:10am

The James Webb Space Telescope has cast its eye on one of the oldest known galaxies, formed just 400 million years after the big bang, and it might be two galaxies merging

An incredibly bright star has lost its gas and is just a leftover core

1 November 2022 - 10:10am

One of the brightest stars we see in the night sky has lost its outer layers of gas and now it is just a rare, stripped-back core

Gravitational waves could reveal the existence of quark matter

1 November 2022 - 10:10am

Two neutron stars smashing together may produce a form of matter not seen before. If that happens, simulations suggest there would be a signal in gravitational waves resulting from the collision

NASA spacecraft records epic ‘marsquakes’ as it prepares to die

28 October 2022 - 8:55am

Nature, Published online: 27 October 2022; doi:10.1038/d41586-022-03447-4

InSight lander reports largest-ever meteorite strikes on Mars, and scientists wish it a fond farewell.