We Finally Know Where the Highest Energy Cosmic Rays are Coming From: Blazars

blazar

Way out there in space is a class of objects called blazars. Think of them as extreme particle accelerators, able to marshall energies a million times stronger than the Large Hadron Collider in Switzerland. It turns out they’re the culprits in one of the great astrophysical mysteries: what creates and propels neutrinos across the universe at blazingly fast speeds? It turns out that the answer’s been there all along: blazars pump out neutrinos and cosmic rays. That’s the conclusion a group of astronomers led by Dr. Sara Buson of Universität Wurzburg in Germany came to as they studied data from a very unique facility here on Earth: the IceCube Neutrino Observatory in Antarctica.

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A New Instrument is Going to the ISS to Study the Climate Impact of Dust in Earth’s Upper Atmosphere

People often seem surprised when they learn that NASA doesn’t just look out to the other planets, stars, and galaxies. It’s also an agency that studies our own home planet—from space! And why not? Earth is part of the solar system, too. So, to that end, there’s a new Earth studies mission called EMIT on its way to the International Space Station. It’s designed to track dust as it moves from one place to another on our planet through through our atmosphere.

The official name of the mission is the Earth Surface Mineral Dust Source Investigation (EMIT, for short). It will use a high-tech imaging spectrometer to study dust around the globe over the next year.

A dust plume stretches over the eastern Mediterranean, shrouding parts of Greece, Turkey, and Cyprus. The June 2020 image has been cropped and enhanced to improve contrast, and lens artifacts have been removed. NASA’s EMIT mission will help scientists better understand how airborne dust affects climate. Credits: NASA
A dust plume stretches over the eastern Mediterranean, shrouding parts of Greece, Turkey, and Cyprus. The June 2020 image has been cropped and enhanced to improve contrast, and lens artifacts have been removed. NASA’s EMIT mission will help scientists better understand how airborne dust affects climate. Credit: NASA
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A Star Came too Close to a Black Hole and was Torn Apart. Surprisingly Little Actually Went In

Close-up of star near a supermassive black hole (artist’s impression). Credit: ESA/Hubble, ESO, M. Kornmesser

What happens when a star wanders too close to a supermassive black hole? The obvious story is that it gets sucked in, never to be seen again. Some of its material gets superheated on the way in and that gives off huge amounts of radiation—usually X-rays. That’s not a wrong explanation, just incomplete. There’s more to the story, thanks to a team of astronomers at the University of California at Berkeley. They used a specialized spectrograph at Lick Observatory to study a tidal disruption event. That’s where a star encountered a black hole. What they found was surprising.

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Dusty Dark Galaxies in the Early Universe Revealed in Various Wavelengths

Artist's impression of a dust-enshrouded starburst (credit: ESO/M. Kornmesser).
Artist's impression of a dust-enshrouded starburst (credit: ESO/M. Kornmesser).

Well, this is the week for distant galaxies, isn’t it? Not only has JWST revealed some of the most distant ones ever seen in infrared, but other observatories are studying them, too. Astronomers at the Cosmic Dawn Center in Copenhagen recently discovered several interesting ones in the early Universe. However, they had to get through clouds of dust to do it. Their observations revealed several interesting characteristics of objects that existed when the Universe was only a tenth of its current age.

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Good News! One JWST Picture Early!

For everybody waiting with bated breath for Tuesday’s release of the first James Webb Space Telescope (JWST) images, NASA’s doing a bit of a tease. They’re releasing one image a day early on Monday afternoon. And, the announcer will be the President of the United States, Mr. Joseph R. Biden. Joining him will be NASA Administrator Bill Nelson, who will conduct this one-of-a-kind White House astronomy briefing. It’s all part of the buildup to the big reveals on Tuesday.

What's JWST going to show us first? There's a sneak preview on Monday. Artist impression of the James Webb Space Telescope. Credit: ESA.
What’s JWST going to show us first? There’s a sneak preview on Monday. Credit: ESA.
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When did the Sun Blow Away the Solar Nebula?

Young stars have a disk of gas and dust around them called a protoplanetary disk. Credit: NASA/JPL-Caltech

The story of our solar system’s origin is pretty well known. It goes like this: the Sun began as a protostar in its “solar nebula” over 4.5 billion years ago. Over the course of several million years, the planets emerged from this nebula and it dissipated away. Of course, the devil is in the details. For example, exactly how long did the protoplanetary disk that gave birth to the planets last? A recent paper submitted to the Journal of Geophysical Research takes a closer look at the planetary birth crèche. In particular, it shows how the magnetism of meteorites helps tell the story.

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One Star Flies Past the Milky Way’s Black Hole at 3% the Speed of Light

Orbits of stars near Sagittarius A*. Credit: ESO/M. Parsa/L. Calçada

There’s a population of stars in the heart of our galaxy whipping around Sagittarius A* (the Milky Way’s central supermassive black hole). Astronomers just found the closest, fastest one (so far). It’s called S4716 and it orbits Sag A* once every four years. That makes it officially the fastest star moving at the heart of our galaxy. To give you some perspective, the Sun moves around the center of the galaxy at a much more leisurely pace once every 230 million years.

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Most Black Holes Spin Rapidly. This one… Doesn’t

This is the first image of Sgr A*, the supermassive black hole at the centre of our galaxy. Credit: EHT
A Chandra X-ray Observatory view of the supermassive black hole at the heart of quasar H1821+643. Courtesy NASA/CXC/Univ. of Cambridge/J. Sisk-Reynés et al.
A Chandra X-ray Observatory view of the supermassive black hole at the heart of quasar H1821+643. Courtesy NASA/CXC/Univ. of Cambridge/J. Sisk-Reynés et al.

Black holes. They used to be theoretical, up until the first one was found and confirmed back in the late 20th Century. Now, astronomers find them all over the place. We even have direct radio images of two black holes: one in M87 and Sagittarius A* in the center of our galaxy. So, what do we know about them? A lot. But, there’s more to find out. A team of astronomers using Chandra X-ray Observatory data has made a startling discovery about a central supermassive black hole in a quasar embedded in a distant galaxy cluster. What they found provides clues to the origin and evolution of supermassive black holes.

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Red Supergiant Stars Bubble and Froth so Much That Their Position in the Sky Seems to Dance Around

This artist’s impression shows the red supergiant star. Using ESO’s Very Large Telescope Interferometer, an international team of astronomers have constructed the most detailed image ever of this, or any star other than the Sun. Credit: ESO/M. Kornmesser

Making a 3D map of our galaxy would be easier if some stars behaved long enough to get good distances to them. However, red supergiants are the frisky kids on the block when it comes to pinning down their exact locations. That’s because they appear to dance around, which makes pinpointing their place in space difficult. That wobble is a feature, not a bug of these massive old stars and scientists want to understand why.

So, as with other challenging objects in the galaxy, astronomers have turned to computer models to figure out why. In addition, they are using Gaia mission position measurements to get a handle on why red supergiants appear to dance.

Artist’s impression of the red supergiant star Betelgeuse as it was revealed with ESO’s Very Large Telescope. It shows a boiling surface and material shed by the star as it ages. Credit: ESO/L.Calçada
Artist’s impression of the red supergiant star Betelgeuse as it was revealed with ESO’s Very Large Telescope. It shows a boiling surface and material shed by the star as it ages. Credit: ESO/L.Calçada
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A Dying Star’s Last Act was to Destroy all Its Planets

Artist's rendition of a white dwarf from the surface of an orbiting exoplanet. Astronomers have found two giant planet candidates orbiting two white dwarfs. More proof that giant planets can surve their stars' red giant phases. Image Credit: Madden/Cornell University

When white dwarfs go wild, their planets suffer through the resulting chaos. The evidence shows up later in and around the dying star’s atmosphere after it gobbles up planetary and cometary debris. That’s the conclusion a team of UCLA astronomers came to after studying the nearby white dwarf G238-44 in great detail. They found a case of cosmic cannibalism at this dying star, which lies about 86 light-years from Earth.

If that star were in the place of our Sun, it would ingest the remains of planets, asteroids, and comets out to the Kuiper Belt. That expansive buffet makes this stellar cannibalism act one of the most widespread ever seen.

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