Astronomers Have Mapped the Milky Way's Magnetic Fields in 3D

Magnetic fields mapped within the Whirlpool Galaxy. Credit: NASA, SOFIA science team, ESA, STScI

Our galaxy is filled with magnetic fields. They come not just from stars and planets, but from dusty stellar nurseries and the diffuse hydrogen gas of interstellar space. We’ve long known of this galactic magnetic field, but mapping it in detail has posed a challenge. Now a new study gives us a detailed 3-dimensional map of these fields, with a few surprises.

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The Second Most Energetic Cosmic Ray Ever Found

An example of a cosmic-ray extensive air shower recorded by the Subaru Telescope. The highlighted tracks, which are mostly aligned in similar directions, show the shower particles induced from a high-energy cosmic ray. Credit: NAOJ/Hyper Suprime-Cam (HSC) Collaboration

“Oh My God,” someone must have said in 1991 when researchers detected the most energetic cosmic ray ever to strike Earth. Those three words were adopted as the name for the phenomenon: the Oh-My-God particle. Where did it come from?

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Webb’s Infrared Eye Reveals the Heart of the Milky Way

The full view of the NASA/ESA/CSA James Webb Space Telescope’s NIRCam (Near-Infrared Camera) instrument reveals a 50 light-years-wide portion of the Milky Way’s dense centre. An estimated 500,000 stars shine in this image of the Sagittarius C (Sgr C) region, along with some as-yet unidentified features. Image Credit: NASA, ESA, CSA, STScI, S. Crowe (UVA)

The JWST is taking a break from studying the distant Universe and has trained its infrared eye on the heart of the Milky Way. The world’s most powerful space telescope has uncovered some surprises and generated some stunning images of the Milky Way’s galactic center (GC.) It’s focused on an enormous star-forming region called Sagittarius C (Sgr C).

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The Tarantula Nebula Shouldn’t Be Forming Stars. What’s Going On?

30 Doradus, also known as the Tarantula Nebula, is a region in the Large Magellanic Cloud. Streamlines show the magnetic field morphology from SOFIA HAWC+ polarization maps. These are superimposed on a composite image captured by the European Southern Observatory’s Very Large Telescope and the Visible and Infrared Survey Telescope for Astronomy. Credit: Background: ESO, M.-R. Cioni/VISTA Magellanic Cloud survey. Acknowledgment: Cambridge Astronomical Survey Unit. Streamlines: NASA/SOFIA

The Tarantula Nebula is a star formation region in the Large Magellanic Cloud (LMC). Tarantula is about 160,000 light-years away and is highly luminous for a non-stellar object. It’s the brightest and largest star formation region in the entire Local Group of galaxies.

But it shouldn’t be.

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These New Computer Simulations of the Sun are Hypnotic

Computer simulation of magnetic structures in solar-like conditions. Image: Jörn Warnecke

It’s almost impossible to over-emphasize the primal, raging, natural power of a star. Our Sun may appear benign in simple observations, but with the advanced scientific instruments at our disposal in modern times, we know differently. In observations outside the narrow band of light our eyes can see, the Sun appears as an enraged, infuriated sphere, occasionally hurling huge jets of plasma into space, some of which slam into Earth.

Jets of plasma slamming into Earth isn’t something to be celebrated (unless you’re in a weird cult); it can cause all kinds of problems.

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New Images Reveal the Magnetic Fields in the Horsehead Nebula

Magnetic field detections overlaid on a two-color composite of Hubble Space Telescope image taken at two near-IR wavelengths (Mikulski Archive for Space Telescopes). Black and orange segments show magnetic field orientations inferred from JCMT and Palomar Observatory. Credit: Hwang et al. 2023.

Located near the summit of Maunakea, Hawaii, the 15-meter (~49 ft) James Clerk Maxwell Telescope (JCMT) at the East Asia Observatory (EAO) is the largest telescope in the world designed to operate exclusively in the submillimetre-wavelength. In 2018, Molokai’i High School alumna Mallory Go was awarded time with the JCMT under the Maunakea Scholars program. With the assistance of EAO astronomer Dr. Harriet Parsons, Go obtained unique images of the Horsehead Nebula in polarized light, which revealed the nebula’s magnetic fields.

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Meteorites Store a Magnetic Memory of the Early Solar System

Black Beauty, or NWA 7034, is a Martian meteorite thought to have formed at a time when the Red Planet harbored a magnetic field. Credit: C Agee, Institute of Meteoritics, UNM; NASA

Although they are thought of as rare, meteorites are actually quite common. About 40,000 tons of meteorites strike Earth every day. Most of them land in the ocean, and most are quite tiny, but they are still common enough that hobbyists all over the world find meteorites all the time. The most common place to find them is in arid regions where their coloring can stand out from the terrain. But even then a meteorite can be difficult to distinguish from terrestrial rocks.

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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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Even the Largest Structures in the Universe Have a Magnetic Field

A composite image showing the magnetic fields of the cosmic web. Credit: Vernstrom et al

The universe is filled with magnetic fields. Although the universe is electrically neutral, atoms can be ionized into positively charged nuclei and negatively charged electrons. When those charges are accelerated, they create magnetic fields. One of the most common sources of magnetic fields on large scales comes from the collisions between and within interstellar plasma. This is one of the major sources of magnetic fields for galactic-scale magnetic fields.

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A Fast-Moving Star is Colliding With Interstellar gas, Creating a Spectacular bow Shock

A multi-wavelength view of Zeta Ophiuchi. Credit: X-ray: NASA/CXC/Dublin Inst. Advanced Studies/S. Green et al.; Infrared: NASA/JPL/Spitzer

Zeta Ophiuchi has had an interesting life. It began as a typical large star about twenty times more massive than the Sun. It spent its days happily orbiting a large companion star until its companion exploded as a supernova about a million years ago. The explosion ejected Zeta Ophiuchi, so now it is speeding away through interstellar space. Of course, the supernova also expelled the outer layers of the companion star, so rather than empty space, our plucky star is speeding through the remnant gas as well. As they say on Facebook, it’s complicated. And that’s great news for astronomers, as a recent study shows.

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