Simulating the Last Moments Before Neutron Stars Merge

Volume rendering of density in a simulation of a binary neutron star merger. New research shows that neutrinos created in the hot interface between the merging stars can be briefly trapped and remain out of equilibrium with the cold cores of the merging stars for 2 to 3 milliseconds. Credit: David Radice/Penn State

When stars reach the end of their life cycle, they shed their outer layers in a supernova. What is left behind is a neutron star, a stellar remnant that is incredibly dense despite being relatively small and cold. When this happens in binary systems, the resulting neutron stars will eventually spiral inward and collide. When they finally merge, the process triggers the release of gravitational waves and can lead to the formation of a black hole. But what happens as the neutron stars begin merging, right down to the quantum level, is something scientists are eager to learn more about.

When the stars begin to merge, very high temperatures are generated, creating “hot neutrinos” that remain out of equilibrium with the cold cores of the merging stars. Ordinarily, these tiny, massless particles only interact with normal matter via weak nuclear forces and possibly gravity. However, according to new simulations led by Penn State University (PSU) physicists, these neutrinos can weakly interact with normal matter during this time. These findings could lead to new insights into these powerful events.

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Matched Twin Stars are Firing Their Jets Into Space Together

This artist’s concept shows two young stars nearing the end of their formation. Encircling the stars are disks of leftover gas and dust from which planets may form. Jets of gas shoot away from the stars’ north and south poles. Credit: NASA

Since it began operating in 2022, the James Webb Space Telescope (JWST) has revealed some surprising things about the Universe. The latest came when a team of researchers used Webb‘s Mid-Infrared Instrument (MIRI) to observe Rho Ophiuchi, the closest star-forming nebula to Earth, about 400 light-years away. While at least five telescopes have studied the region since the 1970s, Webb’s unprecedented resolution and specialized instruments revealed what was happening at the heart of this nebula.

For starters, while observing what was thought to be a single star (WL 20S), the team realized they were observing a pair of young stars that formed 2 to 4 million years ago. The MIRI data also revealed that the twin stars have matching jets of hot gas (aka stellar jets) emanating from their north and south poles into space. The discovery was presented at the 244th meeting of the American Astronomical Society (224 AAS) on June 12th. Thanks to additional observations made by the Atacama Large Millimeter/submillimeter Array (ALMA), the team was surprised to notice large clouds of dust and gas encircling both stars.

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New Simulation Explains how Supermassive Black Holes Grew so Quickly

Supermassive Black Hole Survey. Credit: ESA/XMM-Newton/PSU/F. Zou et al./N.Trehnl/The TNG Collaboration

One of the main scientific objectives of next-generation observatories (like the James Webb Space Telescope) has been to observe the first galaxies in the Universe – those that existed at Cosmic Dawn. This period is when the first stars, galaxies, and black holes in our Universe formed, roughly 50 million to 1 billion years after the Big Bang. By examining how these galaxies formed and evolved during the earliest cosmological periods, astronomers will have a complete picture of how the Universe has changed with time.

As addressed in previous articles, the results of Webb‘s most distant observations have turned up a few surprises. In addition to revealing that galaxies formed rapidly in the early Universe, astronomers also noticed these galaxies had particularly massive supermassive black holes (SMBH) at their centers. This was particularly confounding since, according to conventional models, these galaxies and black holes didn’t have enough time to form. In a recent study, a team led by Penn State astronomers has developed a model that could explain how SMBHs grew so quickly in the early Universe.

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Don't Get Your Hopes Up for Finding Liquid Water on Mars

In the coming decades, NASA and China intend to send the first crewed missions to Mars. Given the distance involved and the time it takes to make a single transit (six to nine months), opportunities for resupply missions will be few and far between. As a result, astronauts and taikonauts will be forced to rely on local resources to meet their basic needs – a process known as in-situ resource utilization (ISRU). For this reason, NASA and other space agencies have spent decades scouting for accessible sources of liquid water.

Finding this water is essential for future missions and scientific efforts to learn more about Mars’s past, when the planet was covered by oceans, rivers, and lakes that may have supported life. In 2018, using ground-penetrating radar, the ESA’s Mars Express orbiter detected bright radar reflections beneath the southern polar ice cap that were interpreted as a lake. However, a team of Cornell researchers recently conducted a series of simulations that suggest there may be another reason for these bright patches that do not include the presence of water.

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NASA is Considering Other Ways of Getting its Mars Samples Home

Artist's impression of the NASA-ESA Mars Sample Return mission. Credit: NASA

In 2021, NASA’s Perseverance rover landed in the Jezero Crater on Mars. For the next three years, this astrobiology mission collected soil and rock samples from the crater floor for eventual return to Earth. The analysis of these samples is expected to reveal much about Mars’ past and how it transitioned from being a warmer, wetter place to the frigid and desiccated place we know today. Unfortunately, budget cuts have placed the future of the proposed NASA-ESA Mars Sample Return (MSR) mission in doubt.

As a result, NASA recently announced that it was seeking proposals for more cost-effective and rapid methods of bringing the samples home. This will consist of three studies by NASA and the Johns Hopkins University Applied Physics Laboratory (JHUAPL). In addition, NASA has selected seven commercial partners for firm-fixed-price contracts for up to $1.5 million to conduct their own 90-day studies. Once complete, NASA will consider which proposals to integrate into the MSR mission architecture.

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Instead of Losing its Atmosphere, an Exoplanet Puffed Up and Held Onto it

Artist's impression of the "hot Neptune" Phoenix orbiting its red giant star. Credit: Credit: Roberto Molar Candanosa/JHU

To date, astronomers have confirmed the existence of 5638 extrasolar planets in 4,199 star systems. In the process, scientists have found many worlds that have defied expectations. This is certainly the case regarding “hot Neptunes,” planets that are similar to the “ice giants” of the outer Solar System but orbit much closer to their stars. But when a Johns Hopkins University-led team of astronomers discovered TIC365102760 b (aka. Pheonix), they observed something entirely unexpected: a Neptune-sized planet that retained its atmosphere by puffing up.

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Astronauts are Practicing Lunar Operations in New Space Suits

Astronauts were fully suited while conducting mission-like maneuvers in the full-scale build of the Starship human landing system’s airlock which will be located inside Starship under the crew cabin. Credit: SpaceX

Through the Artemis Program, NASA will send astronauts to the lunar surface for the first time since 1972. While the challenges remain the same, the equipment has evolved, including the rocket, spacecraft, human landing system (HLS), and space suits. In preparation for Artemis III (planned for September 2026), NASA recently conducted a test where astronauts donned the new space suits developed by Axiom Space and practiced interacting with the hardware that will take them to the Moon.

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Starliner Finally Launches, Carrying Two Astronauts Into Orbit

Boeing's CTS-100 Starliner taking off from Cape Canaveral, Florida, on June 5th, 2024. Credit: NASA

After many delays and two scrubbed launch attempts, Boeing’s CST-100 Starliner successfully launched earlier today! The Crewed Flight Test (CFT) took off from Space Launch Complex-41 at Cape Canaveral Space Force Station, Florida, at 10:52 a.m. EDT (07:52 PDT) atop a ULA Atlas V rocket. For this mission, the capsule is carrying two NASA astronauts: Barry “Butch” Wilmore (commander) and Sunita “Suni” Williams (pilot). They are expected to reach the International Space Station (ISS) at 12:15 p.m. EDT (09:15 a.m. PDT) on Thursday, June 6th.

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Japan’s Lunar Lander Fails to Check-in

Illustration: SLIM lander on the moon
An artist's conception shows Japan's SLIM lander on the moon. Credit: ISAS/JAXA

On January 19th, 2024, the Japanese Aerospace Exploration Agency (JAXA) successfully landed its Smart Lander for Investigating Moon (SLIM) on the lunar surface. In so doing, JAXA became the fifth national space agency to achieve a soft landing on the Moon – after NASA, the Soviet space program (Interkosmos), the European Space Agency, and the China National Space Agency (CNSA). SLIM has since experienced some technical difficulties, which included upending shortly after landing, and had to be temporarily shut down after experiencing power problems when its first lunar night began.

On the Moon, the day/night cycle lasts fourteen days at a time, which has a drastic effect on missions that rely on solar panels. Nevertheless, SLIM managed to reorient its panels and recharge itself and has survived three consecutive lunar nights since it landed. However, when another lunar night began on May 27th, JAXA announced that they had failed to establish communications with the lander. As a result, all science operations were terminated while mission controllers attempt to reestablish communications, which could happen later this month.

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