Researchers Use Ancient Literature to Track 3,000 Years of Auroras

EIELSON AIR FORCE BASE, Alaska -- The Aurora Borealis, or Northern Lights, shines above Bear Lake here Jan. 18. The lights are the result of solar particles colliding with gases in Earth's atmosphere. Early Eskimos and Indians believed different legends about the Northern Lights, such as they were the souls of animals dancing in the sky or the souls of fallen enemies trying to rise again. (U.S. Air Force photo by Senior Airman Joshua Strang)

Auroral activity on Earth varies over time. As the magnetic poles drift, auroras can appear at different latitudes around the globe. Solar activity also affects them, with powerful solar storms pushing the auroras further into mid-latitudes.

In an effort to better understand how auroras move around, how they’ll move in the future, and when powerful solar storms might pose a threat, a team of researchers have tracked auroral activity for the last 3,000 years.

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This is How You Get Moons. An Earth-Sized World Just got Pummeled by Something Huge.

An MIT-led team has discovered evidence of a giant impact in the nearby HD 17255 star system, in which an Earth-sized terrestrial planet and a smaller impactor likely collided at least 200,000 years ago, stripping off part of one planet’s atmosphere. Credits:Image: Mark A. Garlick

Titanic collisions are the norm in young solar systems. Earth’s Moon was the result of one of those collisions when the protoplanet Theia collided with Earth some 4.5 billion years ago. The collision, or series of collisions, created a swirling mass of ejecta that eventually coalesced into the Moon. It’s called the Giant Impact Hypothesis.

Astronomers think that collisions of this sort are a common part of planet formation in young solar systems, where things haven’t settled down into predictability. But seeing any of these collisions around other stars has proved difficult.

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The Early Solar System Had a Gap Where the Asteroid Belt is Today

An MIT study suggests that a mysterious gap existed within the solar system’s protoplanetary disk around 4.567 billion years ago, and likely shaped the composition of the solar system’s planets. This image shows an artist’s interpretation of a protoplanetary disk. Image Credit: National Science Foundation, A. Khan

Wind the cosmic clock back a few billion years and our Solar System looked much different than it does today. About 4.5 billion years ago, the young Sun shone much like it does now, though it was a little smaller. Instead of being surrounded by planets, it was ensconced in a swirling disk of gas and dust. That disk is called a protoplanetary disk and it’s where the planets eventually formed.

There was a conspicuous gap in the early Solar System’s protoplanetary disk, between where Mars and Jupiter are now, and where the modern-day asteroid belt sits. What exactly caused the gap is a mystery, but astronomers think it’s a sign of the processes that governed planet formation.

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The Large Magellanic Cloud Stole one of its Globular Clusters

The Milky Way with the Small and Large Magellanic Clouds on the left. Image Credit: ESO/Y. Beletsky. CC 4.0

Astronomers have known for years that galaxies are cannibalistic. Massive galaxies like our own Milky Way have gained mass by absorbing smaller neighbours.

Now it looks like smaller galaxies like the Large Magellanic Cloud have also feasted on smaller neighbours.

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What Are Your Options When you’ve Only Got Hours or Days to Prevent an Asteroid Impact?

Mining asteroids might be necessary for humanity to expand into the Solar System. But what effect would asteroid mining have on the world's economy? Credit: ESA.

Imagine a scenario where we detect an asteroid heading straight for Earth. Imagine that it will arrive in a couple of days, or worse, only a few hours. What could be done to stop it?

It might be possible to protect ourselves and the planet on such short notice. But we’d have to test and build the right infrastructure to do it.

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What’s Causing the Mysterious Radio Waves Coming From the Center of the Milky Way?

An artist's impression of ASKAP J173608.2-321635, the mysterious radio source at the center of the Milky Way. Image Credit: Sebastian Zentilomo.

The center of the Milky Way is a mysterious place. Astronomers think there’s a supermassive black hole there, though it could be dark matter instead. The region is densely packed with stars, dominated by red giants. And because of all the dust between Earth and the galactic center, we can’t see anything with visible light, ultraviolet light, or low-energy x-rays.

But we can detect radio waves, and there are some unexplained ones coming from the center of the galaxy, and adding to the mystery.

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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.

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Perseverance has Collected its First Sample of Mars and Prepared it for Return to Earth… Eventually

This composite of two images shows the hole drilled by NASA's Perseverance rover during its sucessful sample-collection attempt. Credits: NASA/JPL-Caltech

It’s another first for NASA.

In early September, the Perseverance rover successfully used its robotic arm and drill to drill into a rock and extract a sample. It extracted a rock core about 6 cm (2 in) long and placed it inside a sealed tube. This is the first time a robotic spacecraft has collected a sample from another planet destined for a return to Earth on a separate spacecraft.

Now we wait for the eventual return of the sample to Earth.

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Why Visit Just one Moon When you Could Explore Them all?

Illustration of Jupiter and the Galilean satellites. Credit: NASA

The Solar System’s moons are intriguing objects for exploration. Especially moons like Europa and Enceladus. Their subsurface oceans make them primary targets in the search for life.

But why not send one spacecraft to visit several moons? NASA’s about to launch its Lucy mission which will visit 8 separate asteroids. Could the same be done for a mission to multiple moons?

For a spacecraft to do that, it would have to do a little dance with the notorious three-body problem, which makes a stubborn partner. A new study presents a possible way to do that.

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