magnetic fields Archives

May 10, 2023May 10, 2023 by Brian Koberlein

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.

April 18, 2023April 18, 2023 by Matt Williams

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.

February 26, 2023February 26, 2023 by Brian Koberlein

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.

July 28, 2022July 28, 2022 by Brian Koberlein

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.

May 8, 2022May 8, 2022 by Brian Koberlein

A Supermassive Black Hole Just Flipped its Entire Magnetic Field

Artist illustration of the supermassive black hole in 1ES 1927+654 before the flare. Credit: NASA/Sonoma State University, Aurore Simonnet

Black holes are powerful cosmic engines. They provide the energy behind quasars and other active galactic nuclei (AGNs). This is due to the interaction of matter with its powerful gravitational and magnetic fields.

Technically, a black hole doesn’t have a magnetic field on its own, but the dense plasma surrounding the black hole as an accretion disk does. As the plasma swirls around the black hole, the charged particles within it generate an electrical current and magnetic field. The direction of the plasma flow doesn’t change spontaneously, so one would imagine the magnetic field is very stable. So imagine the surprise of astronomers when they saw evidence that a black hole’s magnetic field had undergone a magnetic reversal.

March 17, 2022March 17, 2022 by Evan Gough

A Pulsar is Blasting out Jets of Matter and Antimatter

This image from NASA's Chandra X-ray Observatory and ground-based optical telescopes shows an extremely long beam, or filament, of matter and antimatter extending from a relatively tiny pulsar, as reported in our latest press release. With its tremendous scale, this beam may help explain the surprisingly large numbers of positrons, the antimatter counterparts to electrons, scientists have detected throughout the Milky Way galaxy. Image Credit: X-ray: NASA/CXC/Stanford Univ./M. de Vries; Optical: NSF/AURA/Gemini Consortium

Why is there so much antimatter in the Universe? Ordinary matter is far more plentiful than antimatter, but scientists keep detecting more and more antimatter in the form of positrons. More positrons reach Earth than standard models predict. Where do they come from?

Scientists think pulsars are one source, and a new study strengthens that idea.

January 23, 2022January 23, 2022 by Brian Koberlein

A Worldwide Search for Dark Matter Fails to Turn up a Signal for This Mysterious Particle

Simulation of dark matter and gas. Credit: Illustris Collaboration (CC BY-SA 4.0)

Axions are a popular candidate in the search for dark matter. There have been previous searches for these hypothetical particles, all of which have come up with nothing. But recently the results of a new search for dark matter axions have been published…and has also found nothing. Still, the study is interesting because of the nature and scale of the search.

December 13, 2021December 13, 2021 by Andy Tomaswick

M87’s Supermassive Black Hole is Spewing out a Spiraling jet of Material

Patterns in nature often occur in more than one place. Spirals, symmetry, and chaos all impact natural phenomena, from the shape of a shell to the course of a river. So it shouldn’t come as a surprise that one of the most famous and fundamental shapes from biology also appears in astrophysics. Yes, scientists have found a double-helix structure in the magnetic field of M87. And it looks just like a super enlarged DNA strand.

October 18, 2021October 18, 2021 by Evan Gough

A Magnetic Tunnel Surrounds the Earth

The sky as it would appear in radio polarized waves. The Van-Gogh-like lines show magnetic field orientation. Image Credit: Pixabay/wal_172619, with edits by J. West.

What if our eyes could see radio waves?

If we could, we might be able to look up into the sky and see a tunnel of rope-like filaments made of radio waves. The structure would be about 1,000 light-years long and would be about 350 light-years away.

This tunnel explains two of the brightest radio features in the sky.

September 29, 2021September 29, 2021 by Brian Koberlein

Aging White Dwarfs Become Even More Magnetic

An artist view of a highly magnetized neutron star -- a magnetar. It's thought that these objects have solid surfaces and suffer eruptions when their magnetic fields are disturbed. Credit: Carl Knox/ OzGrav

In a few billion years the Sun will end its life as a white dwarf. As the Sun runs out of hydrogen to fuse for energy it will collapse under its own weight. Gravity will compress the Sun until it’s roughly the size of Earth, at which point a bit of quantum physics will kick in. Electrons from the Sun’s atoms will push back against gravity, creating what is known as degeneracy pressure. Once a star reaches this state it will cool over time, and the once brilliant star will eventually fade into the dark.