Februar 2025 – NHI Space

James Webb Space Telescope will study asteroid 2024 YR4

Februar 13, 2025Februar 13, 2025adminLeave a Comment

Astronomers will use the NASA/ESA/CSA James Webb Space Telescope to improve our understanding of the size and orbit of asteroid 2024 YR4, which has a very small chance of impacting Earth in 2032.
Why is asteroid 2024 YR4 important?
Asteroid 2024 YR4 was discovered on 27 December 2024. As of 10 February 2025, it has an approximately 98% chance of safely passing Earth on 22 December 2032. Astronomers are working to reduce our uncertainty about the asteroid’s orbit and rule out any impact risk, but it will fade from view from Earth in a few months’ time, and a small chance of impact may persist until it becomes visible again in 2028.
The chance of impact is very slim, and the asteroid is small enough that the effects of any potential impact would be on a local scale, but the situation is significant enough to warrant the attention of the global planetary defence community.
What do we hope to learn by studying the asteroid with Webb?
Astronomers around the world are using powerful telescopes to measure the asteroid’s orbit as accurately as possible. But knowing its orbit will only tell us if the asteroid could impact Earth, not how significant an impact could be.
To accurately assess the hazard posed by asteroid 2024 YR4, we need a more precise estimate of its size. Our current estimate, 40—90 m, has not changed much since the asteroid was first discovered in December 2024, despite many follow-up observations.
This is because astronomers are currently limited to studying the asteroid via the visible light it reflects from the Sun. In general, the brighter the asteroid, the larger it is, but this relationship strongly depends on how reflective the asteroid’s surface is. 2024 YR4 could be 40 m across and very reflective, or 90 m across and not very reflective.
It is very important that we improve our size estimate for 2024 YR4: the hazard represented by a 40 m asteroid is very different from that of a 90 m asteroid.
Webb is able to study the infrared light (heat) that 2024 YR4 emits, rather than the visible light it reflects. Infrared observations can offer a much better estimate of an asteroid’s size, as explained in an article recently published in the journal Nature, co-authored by members of ESA’s Planetary Defence Office.
Astronomers will use Webb’s MIRI instrument to get a much more precise estimate of the asteroid’s size. This, in turn, will be used by ESA, NASA, and other organisations to more confidently assess the hazard and determine any necessary response.
Observations made using Webb’s NIRCam instrument will complement MIRI’s thermal data and will also provide additional measurements of the asteroid’s position once it is beyond the reach of Earth-based telescopes.

When will the observations of 2024 YR4 take place?
The first round of observations will take place in early March, just as the asteroid becomes observable by Webb and is at its brightest. The second round of observations will take place in May. Astronomers will use these later observations to study how the temperature of 2024 YR4 has changed as it has moved further away from the Sun and to provide the final measurements of the asteroid’s orbit until it returns into view in 2028.
Who requested the observations?
Each year, a small amount of Webb’s observational time is reserved for ‘Director’s Discretionary Time’. This time is set aside for time-critical or new discoveries made after the annual Webb proposal deadline that cannot wait for the next proposal cycle.
An international team of astronomers from institutions including ESA’s Planetary Defence Office submitted a proposal to use some of this time to study 2024 YR4. This proposal has now been accepted. The total observation time will amount to around four hours. The resulting data will be publicly available.

About Webb
Webb is the largest, most powerful telescope ever launched into space. Under an international collaboration agreement, ESA provided the telescope’s launch service, using the Ariane 5 launch vehicle. Working with partners, ESA was responsible for the development and qualification of Ariane 5 adaptations for the Webb mission and for the procurement of the launch service by Arianespace. ESA also provided the workhorse spectrograph NIRSpec and 50% of the mid-infrared instrument MIRI, which was designed and built by a consortium of nationally funded European Institutes (The MIRI European Consortium) in partnership with JPL and the University of Arizona.
Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).

Many thanks to the team at ESA’s Planetary Defence Office and to Andrew Rivkin of the Johns Hopkins University Applied Physics Laboratory, Principal Investigator for the James Webb Space Telescope observations of 2024 YR4, for their input to this post.

Source: https://blogs.esa.int/rocketscience/2025/02/10/james-webb-space-telescope-will-study-asteroid-2024-yr4/

Black Holes Can Cook for Themselves, Chandra Study Shows

Februar 2, 2025Februar 2, 2025adminLeave a Comment

Astronomers have taken a crucial step in showing that the most massive black holes in the universe can create their own meals. Data from NASA’s Chandra X-ray Observatory and the Very Large Telescope (VLT) provide new evidence that outbursts from black holes can help cool down gas to feed themselves.
This study was based on observations of seven clusters of galaxies. The centers of galaxy clusters contain the universe’s most massive galaxies, which harbor huge black holes with masses ranging from millions to tens of billions of times that of the Sun. Jets from these black holes are driven by the black holes feasting on gas.
These images show two of the galaxy clusters in the study, the Perseus Cluster and the Centaurus Cluster. Chandra data represented in blue reveals X-rays from filaments of hot gas, and data from the VLT, an optical telescope in Chile, shows cooler filaments in red.
The results support a model where outbursts from the black holes trigger hot gas to cool and form narrow filaments of warm gas. Turbulence in the gas also plays an important role in this triggering process.
According to this model, some of the warm gas in these filaments should then flow into the centers of the galaxies to feed the black holes, causing an outburst. The outburst causes more gas to cool and feed the black holes, leading to further outbursts.
This model predicts there will be a relationship between the brightness of filaments of hot and warm gas in the centers of galaxy clusters. More specifically, in regions where the hot gas is brighter, the warm gas should also be brighter. The team of astronomers has, for the first time, discovered such a relationship, giving critical support for the model.
This result also provides new understanding of these gas-filled filaments, which are important not just for feeding black holes but also for causing new stars to form. This advance was made possible by an innovative technique that isolates the hot filaments in the Chandra X-ray data from other structures, including large cavities in the hot gas created by the black hole’s jets.
The newly found relationship for these filaments shows remarkable similarity to the one found in the tails of jellyfish galaxies, which have had gas stripped away from them as they travel through surrounding gas, forming long tails. This similarity reveals an unexpected cosmic connection between the two objects and implies a similar process is occurring in these objects.
This work was led by Valeria Olivares from the University of Santiago de Chile, and was published Monday in Nature Astronomy. The study brought together international experts in optical and X-ray observations and simulations from the United States, Chile, Australia, Canada, and Italy. The work relied on the capabilities of the MUSE (Multi Unit Spectroscopic Explorer) instrument on the VLT, which generates 3D views of the universe.
NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
Read more from NASA’s Chandra X-ray Observatory.
Learn more about the Chandra X-ray Observatory and its mission here:
https://www.nasa.gov/chandra
https://chandra.si.edu
Visual Description
This release features composite images shown side-by-side of two different galaxy clusters, each with a central black hole surrounded by patches and filaments of gas. The galaxy clusters, known as Perseus and Centaurus, are two of seven galaxy clusters observed as part of an international study led by the University of Santiago de Chile.
In each image, a patch of purple with neon pink veins floats in the blackness of space, surrounded by flecks of light. At the center of each patch is a glowing, bright white dot. The bright white dots are black holes. The purple patches represent hot X-ray gas, and the neon pink veins represent filaments of warm gas. According to the model published in the study, jets from the black holes impact the hot X-ray gas. This gas cools into warm filaments, with some warm gas flowing back into the black hole. The return flow of warm gas causes jets to again cool the hot gas, triggering the cycle once again.
While the images of the two galaxy clusters are broadly similar, there are significant visual differences. In the image of the Perseus Cluster on the left, the surrounding flecks of light are larger and brighter, making the individual galaxies they represent easier to discern. Here, the purple gas has a blue tint, and the hot pink filaments appear solid, as if rendered with quivering strokes of a paintbrush. In the image of the Centaurus Cluster on the right, the purple gas appears softer, with a more diffuse quality. The filaments are rendered in more detail, with feathery edges, and gradation in color ranging from pale pink to neon red.

Source: https://www.nasa.gov/image-article/black-holes-can-cook-for-themselves-chandra-study-shows/

6 Things to Know About SPHEREx, NASA’s Newest Space Telescope

Februar 2, 2025Februar 2, 2025adminLeave a Comment

NASA’s SPHEREx observatory undergoes testing at BAE Systems in Boulder, Colorado, in August 2024. Launching no earlier than Feb. 27, 2025, the mission will make the first all-sky spectroscopic survey in the near-infrared, helping to answer some of the biggest questions in astrophysics.
Credit: BAE Systems/NASA/JPL-Caltech

Shaped like a megaphone, the upcoming mission will map the entire sky in infrared light to answer big questions about the universe.
Expected to launch no earlier than Thursday, Feb. 27, from Vandenberg Space Force Base in California, NASA’s SPHEREx space observatory will provide astronomers with a big-picture view of the cosmos like none before. Short for Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer, SPHEREx will map the entire celestial sky in 102 infrared colors, illuminating the origins of our universe, galaxies within it, and life’s key ingredients in our own galaxy. Here are six things to know about the mission.
1. The SPHEREx space telescope will shed light on a cosmic phenomenon called inflation.
In the first billionth of a trillionth of a trillionth of a second after the big bang, the universe increased in size by a trillion-trillionfold. Called inflation, this nearly instantaneous event took place almost 14 billion years ago, and its effects can be found today in the large-scale distribution of matter in the universe. By mapping the distribution of more than 450 million galaxies, SPHEREx will help scientists improve our understanding of the physics behind this extreme cosmic event.
2. The observatory will measure the collective glow from galaxies near and far.
Scientists have tried to estimate the total light output from all galaxies throughout cosmic history by observing individual galaxies and extrapolating to the trillions of galaxies in the universe. The SPHEREx space telescope will take a different approach and measure the total glow from all galaxies, including galaxies too small, too diffuse, or too distant for other telescopes to easily detect. Combining the measurement of this overall glow with other telescopes’ studies of individual galaxies will give scientists a more complete picture of all the major sources of light in the universe.
3. The mission will search the Milky Way galaxy for essential building blocks of life.
Life as we know it wouldn’t exist without basic ingredients such as water and carbon dioxide. The SPHEREx observatory is designed to find these molecules frozen in interstellar clouds of gas and dust, where stars and planets form. The mission will pinpoint the location and abundance of these icy compounds in our galaxy, giving researchers a better sense of their availability in the raw materials for newly forming planets.

E2-PIA10181 Molecular clouds like this one, called Rho Ophiuchi, are collections of cold gas and dust in space where stars and planets can form. SPHEREx will survey such regions throughout the Milky Way galaxy to measure the abundance of water ice and other frozen molecules.
Credit: NASA/JPL-Caltech

4. It adds unique strengths to NASA’s fleet of space telescopes.
Space telescopes like NASA’s Hubble and Webb have zoomed in on many corners of the universe to show us planets, stars, and galaxies in high resolution. But some questions — like how much light do all the galaxies in the universe collectively emit? — can be answered only by looking at the big picture. To that end, the SPHEREx observatory will provide maps that encompass the entire sky. Objects of scientific interest identified by SPHEREx can then be studied in more detail by targeted telescopes like Hubble and Webb.
5. The SPHEREx observatory will make the most colorful all-sky map ever.
The SPHEREx observatory “sees” infrared light. Undetectable to the human eye, this range of wavelengths is ideal for studying stars and galaxies. Using a technique called spectroscopy, the telescope can split the light into its component colors (individual wavelengths), like a prism creates a rainbow from sunlight, in order to measure the distance to cosmic objects and learn about their composition. With SPHEREx’s spectroscopic map in hand, scientists will be able to detect evidence of chemical compounds, like water ice, in our galaxy. They’ll not only measure the total amount of light emitted by galaxies in our universe, but also discern how bright that total glow was at different points in cosmic history. And they’ll chart the 3D locations of hundreds of millions of galaxies to study how inflation influenced the large-scale structure of the universe today.
6. The spacecraft’s cone-shaped design helps it stay cold and see faint objects.
The mission’s infrared telescope and detectors need to operate at around minus 350 degrees Fahrenheit (about minus 210 degrees Celsius). This is partly to prevent them from generating their own infrared glow, which might overwhelm the faint light from cosmic sources. To keep things cold while also simplifying the spacecraft’s design and operational needs, SPHEREx relies on an entirely passive cooling system — no electricity or coolants are used during normal operations. Key to making this feat possible are three cone-shaped photon shields that protect the telescope from the heat of Earth and the Sun, as well as a mirrored structure beneath the shields to direct heat from the instrument out into space. Those photon shields give the spacecraft its distinctive outline.
More About SPHEREx
SPHEREx is managed by NASA’s Jet Propulsion Laboratory for the agency’s Astrophysics Division within the Science Mission Directorate at NASA Headquarters in Washington. BAE Systems (formerly Ball Aerospace) built the telescope and the spacecraft bus. The science analysis of the SPHEREx data will be conducted by a team of scientists located at 10 institutions in the U.S., two in South Korea, and one in Taiwan. Data will be processed and archived at IPAC at Caltech, which manages JPL for NASA. The mission principal investigator is based at Caltech with a joint JPL appointment. The SPHEREx dataset will be publicly available at the NASA/IPAC Infrared Science Archive.
For more information about the SPHEREx mission visit:
https://www.jpl.nasa.gov/missions/spherex/

Source: https://www.jpl.nasa.gov/news/6-things-to-know-about-spherex-nasas-newest-space-telescope/

Aliens From a Parallel Universe May Be All Around Us—And We Don’t Even Know It, Study Suggests

Februar 2, 2025Februar 2, 2025adminLeave a Comment

Published in 1962 by American astronomer Frank Drake, Ph.D., the eponymous Drake equation sought to estimate the number of detectable alien civilizations in the Milky Way galaxy. This equation takes into account the average rate of star formation in the galaxy, the fraction of those stars that have orbiting planets, and the average number of those planets per star that can support life. It gets hairier: This formula also considers what fraction of those planets could support intelligent organisms, and whether those organisms can develop technology capable of contacting others.
Now, researchers in Switzerland and the U.K. have homed in on one particular aspect of this equation to contemplate how a crucial component of our universe affects star formation and, by extension, the possibility of intelligent life. Their paper studies the relationship between the density of a mysterious force in the universe, called dark energy, and the overall number of stars formed in the universe’s history. Published in November 2024 in the journal Monthly Notices of the Royal Astronomical Society, this work describes a new theoretical model of cosmic star formation applied to our universe as well as other possible ones with varying dark energy densities.
In other words, it ponders the likelihood of intelligent life existing in the multiverse.
To approach this question, the team tackled anthropic reasoning. This line of thinking is the idea that we can derive fundamental properties of the universe based on the fact that we exist. There’s so much we don’t know about the universe, but one thing we know for certain is that, at least in one tiny corner, it allows humans to exist. That starting point guides the way for understanding other characteristics of the universe.
Anthropic reasoning can offer explanations for the amount of dark energy in our universe. In the late 1980s, physics Nobel laureate Steven Weinberg used this idea to propose that the observed density of dark energy in the universe informs the existence of intelligent life within it. He contemplated that larger densities of dark energy would cause the universe to expand faster, negating gravity’s effort to clump matter together into galaxies, which would discourage star formation, and therefore, life.
Dark energy is an enigmatic force that may be causing the universe to expand at an accelerated rate. While it doesn’t explicitly factor into the Drake equation, dark energy does relate to star formation, which is key to the formula. In the same way that life on Earth wouldn’t exist without our sun, stars are a prerequisite for the formation of intelligent life. So, contemplating how varying amounts of dark energy in the universe impact star formation could tell us about other possible universes, too.
“Since stars are a precondition for the emergence of life as we know it, we then ask whether it would be easier for intelligent life to spawn in our Universe, or in a hypothetical universe with a different dark energy content,” the paper’s first author Daniele Sorini, Ph.D, a postdoctoral research associate in cosmology and astrophysics at Durham University’s Institute for Computational Cosmology in the U.K., says in an email to Popular Mechanics.
Dark energy is baffling. According to Sorini, “while we can measure the density of dark energy, we do not really know what it is.” Still, measuring it is useful. For example, in the paper, Sorini and his team plot the efficiency of star formation throughout the cosmos in relation to varying amounts of dark energy density. The team found that the amount of stars formed in the universe’s history is maximized if dark energy density is about one-tenth its observed value. That means, hypothetically, the ideal universe for forming life—because the formation of life comes from the formation of stars—would have less dark energy than our universe. Assuming that this amount is proportional to stars formed, this would make for the ideal universe to create intelligent life. In this optimal scenario, 27 percent of ordinary matter in the universe converts to stars, while in our universe, it’s only 23 percent. This gap demonstrates that while our universe is close to hosting the optimal conditions for life, it’s still not the most ideal.
Cosmic star formation continues to decrease with higher dark energy densities. Hypothetically, a universe with increasing dark energy density is less hospitable to the formation of intelligent life. Likewise, Weinberg posited that very few universes with intelligent life in the multiverse would have limited dark energy density.
As Weinberg had done, Sorini and his co-authors pondered what might change if a universe contained a different density of dark energy. But, considering a multiverse wherein each universe contains a different dark energy density—observed by one intelligent observer—the team found that 99.5 percent of these universes boasted a higher dark energy density than our own universe’s.
“This might seem at odds with the fact that higher dark energy abundance leads to lower likelihood of generating intelligent life,” Sorini says. “But there is no contradiction.” He explains that, individually, universes with higher dark energy densities contain fewer intelligent observers, though there are many more such universes. The paper’s calculations show that, taken collectively, these multiverses contain intelligent observers.
However, Sorini emphasizes that this paper doesn’t aim to prove the existence of the multiverse or locate extraterrestrial life. Rather, it’s a novel way of considering how dark energy density in the universe could impact star formation, which serves as a proxy for the development of intelligent life.
“Whether the multiverse scenario is real or not is beside the point of our paper,” Sorini says. “It is a thought experiment to understand whether we can provide a suitable explanation of the puzzling observed value of the dark energy density in our universe, based on the fact that we exist.”

source: https://www.popularmechanics.com/science/a63635014/aliens-parallel-universe/