The Crab Nebula Looks Completely Different in X-Rays, Revealing its Magnetic Fields

Credits: Magnetic field lines: NASA/Bucciantini et al; X-ray: NASA/CXC/SAO; Optical: NASA/STScI; Infrared: NASA-JPL-Caltech

Located about 6,500 light-years away in the constellation Taurus resides one of the best-studied cosmological objects known as the Crab Nebula (aka. Messier 1). Originally discovered in the 18th century by English astronomer John Bevis in 1731, the Crab Nebula became the first object included by astronomer Charles Messier in his catalog of Deep Sky Objects. Because of its extreme nature, scientists have been studying the Crab Nebula for decades to learn more about its magnetic field, its high-energy emissions (x-rays), and how these accelerate particles to close to the speed of light.

Astronomers have been particularly interested in studying the polarization of the x-rays produced by the pulsar and what that can tell us about the nebula’s magnetic field. When studies were first conducted in the 1970s, astronomers had to rely on a sounding rocket to get above Earth’s atmosphere and measure the polarization using special sensors. Recently, an international team of astronomers used data obtained by NASA’s Imaging X-ray Polarimetry Explorer (IXPE) to create a detailed map of the Crab Nebula’s magnetic field that has resolved many long-standing mysteries about the object.

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M87 Galaxy Reconstructed in Thrilling 3D

A photo of the huge elliptical galaxy M87 [left] is compared to its three-dimensional shape as gleaned from meticulous observations made with the Hubble and Keck telescopes [right]. Image Credit: NASA, ESA, J. Olmsted (STScI), F. Summers (STScI)C. Ma (UC Berkeley); CC BY 4.0

In astronomy, we speak casually of extremely large numbers and extremely vast distances as if they’re trivial. A supermassive black hole can have several billion solar masses, a distant quasar is 500 million light-years away, etc. Objects like galaxies that are mere tens of millions of light years away start to seem familiar.

But even though our Wikipedia pages are full of data on distant objects, there’s a deceptive lack of understanding of some of their basic properties. Take Messier 87, for example, a galaxy often talked about and seen in images. It’s noteworthy for being home to the first black hole ever imaged.

It’s so far away that astronomers have no real idea what its three-dimensional shape is.

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Astronomers Find a Planet Using Gaia Data

Artist view of a Jupiter-like exoplanet. Credit: NASA/Goddard Space Flight Center/S. Wiessinger

The ESA’s Gaia mission is our most accurate star-measuring spacecraft. It’s busy mapping the positions and radial velocities of one billion stars in the Milky Way. The mission’s goal is to create a representative map of the galaxy’s stellar population with unprecedented accuracy. The mission has released 3 sets of data since its inception, leading to many discoveries.

Now a team of astronomers has found an exoplanet with help from Gaia, an unintended result of the ambitious mission.

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How Many Intergalactic Radio Stations Are Out There?

The Stephans Quintet captured by the James Webb Space Telescope (JWST). Credit: NASA/ESA/CSA

It has been over sixty years since Dr. Frank Drake (father of the Drake Equation) and his colleagues mounted the first Search for Extraterrestrial Intelligence (SETI) survey. This was known as Project Ozma, which relied on the “Big Ear” radio telescope at the National Radio Astronomy Observatory (NRAO) in Greenbank, West Virginia, to look for signs of radio transmissions in Tau Ceti and Epsilon Eridani. Despite the many surveys conducted since then, no definitive evidence of technological activity (i.e., “technosignatures”) has been found.

This naturally raises the all-important question: are we going about the business of SETI wrong? Instead of looking for technosignatures within our galaxy, as all previous SETI surveys have done, should we look for activity beyond our galaxy (from possible Type II and Type III civilizations)? This premise was explored in a recent paper led by researchers from the National Chung Hsing University in Taiwan. Using data from the largest SETI project to date, Breakthrough Listen, the team looked for potential radio technosignatures from extragalactic sources.

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Artificial Intelligence Produces a Sharper Image of M87’s Big Black Hole

The new PRIMO reconstruction of the black hole in M87. This is based on a newly "cleaned-up" image from the Event Horizon Telescope. (Credit: Lia Medeiros et al. / ApJL, 2023)
The new PRIMO reconstruction of the black hole in M87. This is based on a newly "cleaned-up" image from the Event Horizon Telescope. (Credit: Lia Medeiros et al. / ApJL, 2023)

Astronomers have used machine learning to sharpen up the Event Horizon Telescope’s first picture of a black hole — an exercise that demonstrates the value of artificial intelligence for fine-tuning cosmic observations.

The image should guide scientists as they test their hypotheses about the behavior of black holes, and about the gravitational rules of the road under extreme conditions.

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Twinkling Stars Supply the Dust That Leads to Life

Artist’s impression of the star in its multi-million year long and previously unobservable phase as a large, red supergiant. Credit: CAASTRO / Mats Björklund (Magipics)

When low to medium-mass stars exhaust their supply of hydrogen, they exit their main sequence phase and expand to become red giants – what is known as the Asymptotic Giant Branch (AGB) phase. Stars in this phase of their evolution become variable (experiences changes in brightness) to shed their outer lays, spreading dust throughout the interstellar medium (ISM) that is crucial to the development of planetary nebulas and protoplanetary systems. For decades, astronomers have sought to better understand the role Red Giant stars play.

Studying interstellar and protoplanetary dust is difficult because it is so faint in visible light. Luckily, this dust absorbs light and radiates brightly in the infrared (IR), making it visible to IR telescopes. Using archival data from now-retired Akari and Wide-field Infrared Survey Explorer (WISE) missions, a team of Japanese astronomers conducted the first long-period survey of dusty AGBs and observed that the variable intensity of these stars coincides with the amount of dust they produce. Since this dust plays an important role in the formation of planets, this study could shed light on the origins of life.

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We Might be able to Find Evidence for Modified Gravity…in the Earth

Artist's impression of Earth's interior structure. Credit: Argonne National Labs

Testing the possibility of models of gravity different from general relativity may be closer to home than we think. A team of researchers has proposed that we might be able to use seismic motions in the Earth itself to test for modified gravity.

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Primordial Black Holes May Have “Frozen” the Early Universe

Artist's logarithmic scale conception of the observable universe with the Solar System at the center, inner and outer planets, Kuiper belt, Oort cloud, Alpha Centauri, Perseus Arm, Milky Way galaxy, Andromeda galaxy, nearby galaxies, Cosmic Web, Cosmic microwave radiation and the Big Bang's invisible plasma on the edge. Credit: Wikipedia Commons/Pablo Carlos Budassi

Primordial holes formed in the exotic conditions of the big bang may have become their own source of matter and radiation.

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Mother of Dragons: Astronomers Peer Inside the “Dragon Cloud”

The inner core of the "dragon cloud" complex. Image credit: Barnes et al.
The inner core of the "dragon cloud" complex. Image credit: Barnes et al.

How did the most massive stars form? Astronomers have debated their origins for decades. One of the biggest problems facing these theories is the lack of observations. Massive stars are relatively rare, and so it’s hard to catch them in the act of formation. But new observations of the so-called Dragon cloud may hold the clue to answering this mystery.

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