Astronomy

A philosophy department chair arrested at a campus protest offers university presidents a lesson in democracy

Russia may be planning to put a nuclear weapon in orbit. We have known since the 1960s why that is a bad idea

A powerful solar storm in May 2024 created auroras on Mars and provided scientists with crucial information that could aid future crewed missions to the Red Planet.

Using the tools of computational complexity, researchers have discovered it is impossible to figure out whether certain Super Mario Bros levels can be beaten without playing them, even if you use the world's most powerful supercomputer

Using the tools of computational complexity, researchers have discovered it is impossible to figure out whether certain Super Mario Bros levels can be beaten without playing them, even if you use the world's most powerful supercomputer

At first glance, the universe and night sky seem largely unchanging. The reality is very different, even now, a gas cloud is charging toward the Milky Way Galaxy and is expected to crash into us in 27 million years. A team of astronomers hoping to locate the exact position of the expected impact site have been unsuccessful but have accidentally measured the thickness of the Milky Way! Analysing radio data, they have been able to deduce the thickness of the inner and outer regions and discovered a dramatic difference between the two. 

The team of astronomers from the US National Science Foundation’s Green Bank Observatory were attempting to study the Smith Cloud. This high velocity cloud of hydrogen gas is located in the constellation Aquila at a distance of somewhere between 36,000 and 45,000 light years. Previous studies from the Green Bank Observatory have shown the cloud contains at least 1 million times the mass of the Sun and measures 9,800 light years long by 3,300 light years wide. 

A false-color image of the Smith Cloud made with data from the Green Bank Telescope (GBT). New analysis indicates that it is wrapped in a dark matter halo. Credit: NRAO/AUI/NSF

The plan was simple enough, to observe the spot where the cloud is currently interacting with the Milky Way. The observation is tricky enough though as the cloud is on the far side of the Milky Way and there is a lot of stuff in the way! The team, led by Toney Minter used the 20m Green Bank Telescope to search for dust and emissions from hydroxyl molecules (composed of a hydrogen and oxygen molecule.)  What the team expected to see was a difference in composition in the region of the Milky Way interacted with the cloud which, should have very little dust and hydroxyl molecules. Clouds in the Milky Way tend to have both so a difference should be detectable. 

The Robert C. Byrd Green Bank Telescope. Credit: Jay Young.

Minter was candidly open about the study joking ‘I knew there was a low probability that I’d find what I was looking for—and I didn’t,. But this is all part of the scientific process. You learn from what you DO and DON’T find.’

Disappointingly the team did not detect any differences in composition but what they did find was equally as interesting. The study revealed information about the Milky Way itself and the structure of its inner regions. Minter and his team had to look through the Milky Way’s inner regions for their study and what they were able to determine was the thickness of the layer of molecules in the inner Galaxy. The information enabled them to deduce the scale height of the clouds of molecular gas in the inner Milky Way. The results showed that the layer of molecules in the inner region measured 330 light years thick while those in the outer parts measured twice as much, around 660 light years. 

The discovery still leaves questions unanswered. The observation certainly shows the difference in thickness between the inner and outer regions but it doesn’t give any clue as to what is driving the difference. Further observations are now required to follow up on this discovery to try and model the underlying process.  Of course one other question remains unanswered and that is the nature and mechanics of the Smith Cloud and how it will impact our own Galaxy. Far from being disappointed though, Minter stated ‘That’s why astronomy is exciting, our knowledge is always evolving’

Source : While Aiming for Massive Gas Cloud, Astronomers Spot Differences in Thickness of Milky Way Galaxy

The post The Inner and Outer Milky Way Aren’t the Same Thickness, and that’s Surprising appeared first on Universe Today.

Many space fans have been following the successful launch of the Boeing Starliner, another commercial organisation aiming to make space more accessible. It successfully reached the International Space Station, delivering Butch Wilmore and Suni Williams into orbit but it wasn’t without a hitch. Three of its thrusters experienced problems and there were ‘five small leaks on the service module.’ The crew and ground teams are working through safety checks of power and habitability. To ensure a safe return of the astronauts NASA has extended the mission by four days to 18th June. 

Boeing Starliner is a reusable (partly) spacecraft designed to transport crews to low Earth orbit. NASA is the lead customer so, once certification has been achieved, will be used to deliver astronauts regularly to the ISS. It consists of a crew capsule that can be used ten times and an expendable service module. Measuring 4.6 metres in diameter it is slightly larger than the Apollo Command module that was a part of the historic Armstrong, Aldrin and Collins mission to the Moon.

The Apollo 10 command/service module nicknamed “Charlie Brown” orbiting the Moon as seen from the lunar module. Credit: NASA

The Boeing Starliner launch marked its first crewed trip into orbit, with the objective of data collection for certification by NASA for regular crewed missions to ISS. The tests are numerous and include; running the spacecraft in minimal power mode (for when docked to ISS), checking suitability to support crew on its own in the event of an emergency, performing habitability studies for a four person crew and a multitude of other system checks. The module has been docked to ISS since 6th June. 

Teething problems for any new module are always expected but when the word ‘leak’ pops up it is most definitely a cause for concern. In the case of Starliner, five small leaks have been detected in the service module helium manifolds. When Starliner launched, the ground team already knew there was one leak in the propulsion system but now, four more have been detected! The flight engineers initially suspected a flaw in a manifold seal or possibly even faulty installation but now, with the four additional leaks they’re trying to understand if there is a common problem.

The leaks are not the only problem that has been experienced. As Starliner approached ISS, it relied upon precise pulses from the 28 reaction control thrusters. During this critical phase of the docking process, five of them failed. More accurately, the spacecraft control software deduced they were not working and deselected them. The first docking window was missed as a result but the crew were able to test and restart four of the five engines allowing them to safely dock. Engineers are still looking into the thruster problem but are confidence it will allow the safe return of the astronauts. 

International Space Station. Credit: NASA

As for the helium leak, flight engineers have examined the leak rate and confirmed that Starliner has sufficient margin to support a return trip to Earth. With Starliner docked to the ISS the manifolds are all closed preventing any helium loss until the return trip which takes just seven hours. Even with the manifolds open and the rate of leak there is sufficient helium to support 70 hours of flight time. 

Ground support teams are continuing to work through the problems and the return plan. They will explore tolerances and possible operational mitigations for the remainder of the mission. As the team depart from the ISS, no earlier than 18th June they will slowly adjust orbit away from the Space Station. A deorbit burn will be completed before entering the atmosphere and landing in south-western United States.

Source : NASA, Boeing Progress on Testing Starliner with Crew at Space Station

The post Starliner Has Five Leaks appeared first on Universe Today.

It sounded like a nightmare scenario: An astronaut commander on the International Space Station in distress and a flight surgeon on Earth stuck in traffic. But it was all a simulation.

The estimated greenhouse gas emissions caused by the war in Ukraine are equivalent to around 175 million tonnes of carbon dioxide, and Ukraine plans to include the associated climate damage in its compensation claim against Russia

The estimated greenhouse gas emissions caused by the war in Ukraine are equivalent to around 175 million tonnes of carbon dioxide, and Ukraine plans to include the associated climate damage in its compensation claim against Russia

Who's the man who turns the Doctor's head in Regency England in "Doctor Who" episode 6 "Rogue"?

Two NASA astronauts will venture outside the International Space Station today (June 13), and you can watch the action live.

Most neutron stars spin rapidly, completing a rotation in seconds or even a fraction of a second. But astronomers have found one that takes its time, completing a rotation in 54 minutes. What compels this odd object to spin so slowly?

When a massive supergiant star explodes as a supernova, it leaves a collapsed core behind. The extreme pressure forces protons and electrons to combine into neutrons. Since they’re made almost entirely of neutrons, we call them neutron stars. These stellar remnants are extremely small and extremely dense. Only black holes have greater density.

Due to the conservation of angular momentum, neutron stars start to spin rapidly, often rotating as fast as several hundred times per second. Astronomers have found more than 3,000 radio-emitting neutron stars, and out of all of them, only a very small number rotate slowly.

We usually detect neutron stars by their electromagnetic radiation and call them pulsars. Astrophysicists also call the ones with slow rotations long-period radio transients. There’s uncertainty around their slow rotation speeds and if they’re even neutron stars, and the most recently discovered one isn’t helping remove the uncertainty.

In new research in Nature Astronomy, a team of researchers presented the discovery of ASKAP J1935+2148, a long-period radio transient about 16,000 light-years away. The paper is “An emission-state-switching radio transient with a 54-minute period.” The lead author is Dr. Manisha Caleb from the University of Sydney in Australia.

“Long-period radio transients are an emerging class of extreme astrophysical events of which only three are known,” the paper’s authors write. “These objects emit highly polarized, coherent pulses of typically a few tens of seconds duration, and minutes to approximately hour-long periods.”

Researchers have proposed different explanations for these long-period objects, including highly-magnetic white dwarfs and highly-magnetic neutron stars called magnetars. But the research community hasn’t reached a consensus.

ASKAP J1935+2148 has an extremely long period of 53.8 minutes and three distinct emission states. Its bright pulse state lasts between 10 and 50 seconds, and its weaker pulse state, 26 times dimmer, lasts about 370 milliseconds. It also exhibits what’s called a “quenched state” with no pulses.

This image took six hours to acquire and shows the new object close to the magnetar SGR 1935+2154. The six hours of observations revealed the object’s long-period emissions. Image Credit: Caleb, M., Lenc, E., Kaplan, D.L. et al. An emission-state-switching radio transient with a 54-minute period. Nat Astron (2024). CC 4.0

Astronomers discovered the puzzling object accidentally while observing an unrelated gamma-ray burst with the Australian Square Kilometre Array Pathfinder (ASKAP) telescope in October 2022. The observations revealed ASKAP J1935+2148’s bright pulses of radio emissions. In about six hours of observations, the object emitted four bright pulses lasting from 10 to 50 seconds. Light curve inspections and follow-up observations with the MeerKAT radiotelescope revealed the object’s entire pulsing pattern.

“This discovery relied on the combination of the complementary capabilities of ASKAP and MeerKAT telescopes as well as the ability to search for these objects on timescales of minutes while studying how their emission changes from second to second! Such synergies are allowing us to shed new light on how these compact objects evolve,” said Dr. Kaustubh Rajwade, paper co-author and an Astronomer at the University of Oxford.

The three emission states, each different from the others, are puzzling. The researchers needed to verify that each signal from each state came from the same point in the sky. The fact that each signal had the same time of arrival (TOA), as determined by both ASKAP and MeerKAT observations, indicates a single source.

“What is intriguing is how this object displays three distinct emission states, each with properties entirely dissimilar from the others. The MeerKAT radio telescope in South Africa played a crucial role in distinguishing between these states. If the signals didn’t arise from the same point in the sky, we would not have believed it to be the same object producing these different signals.”

ASKAP detected the object’s strong, bright pulse mode, while MeerKAT detected its fainter, weak pulse mode. Both telescopes detected the quiescent mode.

This figure from the research shows the light curves detected by ASKAP and MeerKAT. A critical part of the results is that the ASKAP and MeerKAT arrived in phase with one another. Image Credit: Caleb, M., Lenc, E., Kaplan, D.L. et al. An emission-state-switching radio transient with a 54-minute period. Nat Astron (2024). CC 4.0

“In the study of radio-emitting neutron stars, we are used to extremes, but this discovery of a compact star spinning so slowly and still emitting radio waves was unexpected,” said paper co-author Ben Stappers, Professor of Astrophysics at the University of Manchester. “It is demonstrating that pushing the boundaries of our search space with this new generation of radio telescopes will reveal surprises that challenge our understanding.”

The nature of the emissions and the rate of change of the spin periods strongly suggest that ASKAP J1935+2148 is a neutron star. However, the researchers say they can’t rule out a highly magnetized white dwarf. Since astrophysicists think that white dwarfs become highly magnetized as binaries, and there are no other white dwarfs nearby, the neutron star explanation is more likely.

The object’s radius also doesn’t conform to our understanding of white dwarfs. “However, the implied radius is ~0.8? solar radii, leading us to conclude that this source cannot be expected by standard white-dwarf models,” the researchers explain. White dwarfs are only slightly larger than Earth, which seems to eliminate one as the potential source.

Only follow-up observations and more dedicated studies can reveal the object’s true nature. Either way, whether it’s a white dwarf or a neutron star, the object will open another window into the extreme physics of either type of object. Our understanding of both objects is only decades old, so there’s bound to be lots left to discover.

“It is important that we probe this hitherto unexplored region of the neutron-star parameter space to get a complete picture of the evolution of neutron stars, and this may be an important source to do so,” the authors conclude.

The post Astronomers Find the Slowest-Spinning Neutron Star Ever appeared first on Universe Today.

Watch a new clip from director Eli Roth's upcoming live-action video game adaptation, "Borderlands."

Magnificent spiral galaxy

As the winner of the Longitude prize on antimicrobial resistance is announced, chair of the prize committee Martin Rees, the UK's Astronomer Royal, explains why it pays to reward ideas

As the winner of the Longitude prize on antimicrobial resistance is announced, chair of the prize committee Martin Rees, the UK's Astronomer Royal, explains why it pays to reward ideas

The FDA has authorized just one type of avian flu test, and it is only available to livestock workers

The third episode of "The Acolyte" is a long flashback that adds more layers to both the story being told and the Star Wars universe as a whole.