Primordial Asteroids That Never Suffered Massive Collisions all Seem to be Larger Than 100 km. Why?

2004 EW95, seen in this artist view, may be a primordial asteroid. Credit: M. Kornmesser/European Southern Observatory

Planetary systems form out of the remnant gas and dust of a primordial star. The material collapses into a protoplanetary disk around the young star, and the clumps that form within the disk eventually become planets, asteroids, or other bodies. Although we understand the big picture of planetary formation, we’ve yet to fully understand the details. That’s because the details are complicated.

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An Intermediate-Mass Black Hole Discovered Through the Gravitational Lensing of a Gamma-ray Burst

An intermediate mass black hole lenses light around it. Credit: Carl Knox, OzGrav

Black holes come in three sizes: small, medium, and large. Small black holes are of stellar mass. They form when a large star collapses at the end of its life. Large black holes lurk in the centers of galaxies and are millions or billions of solar masses. Middle-sized black holes are those between 100 to 100,000 solar masses. They are known as Intermediate Mass Black Holes (IMBHs), and they are the kind we least understand.

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A new way to see Inside Neutron Stars

The song of a binary tells us about neutron stars. Credit: University of Bath

Imagine trying to study an object light-years away that is less than 20 kilometers in diameter. The object is so dense that it’s made of material that can’t exist naturally on Earth. This is the challenge astronomers face when studying neutron stars, so they have to devise ingenious ways to do it. Recently a team figured out how to study them by using the power of resonance.

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The Event Horizon Telescope has Revealed the Magnetic Field Lines Around M87's Central Black Hole

Computer simulation of plasma near a black hole. Credit: Hotaka Shiokawa / EHT

In 2019 astronomers captured the first direct image of a black hole. It was an image of the supermassive black hole at the heart of M87. And when many folks saw it, their reaction was “that’s it?” Which is understandable, given that the image is just a blurry, donut-shaped smudge. It isn’t much to look at. But an astronomical image is a small fraction of the data gathered by astronomers. Recently more of that data has been analyzed, including both the polarization of the light and the magnetic field surrounding the black hole.

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Gravitational Lenses Could Allow a Galaxy-Wide Internet

An early NASA concept of an interstellar space probe. Credit: NASA/Johns Hopkins University Applied Physics Laboratory

As Carl Sagan once said, “The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars.” And our first emissaries to the stars will be robotic probes. These interstellar probes will be largely autonomous, but we will want to communicate with them. At the very least we will want them to phone home and tell us what they’ve discovered. The stars are distant, so the probes will need to make a very long-distance call.

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There Could be Magnetic Monopoles Trapped in the Earth's Magnetosphere

A visualization of Earth's magnetosphere. Credit: NASA's Scientific Visualization Studio

Electricity and magnetism have a lot in common. They are connected by the unified theory of electromagnetism, and are in many ways two sides of the same coin. Both can exert forces on charges and magnetic fields. A changing electric field creates a magnetic field and vice versa. Elementary particles can possess electric and magnetic properties. But there is one fundamental difference.

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Wormholes Could Allow Travel Across the Universe, as Long as Your Spacecraft is Microscopic

Artist rendering of a wormhole connecting two galaxies. Credit: Davide and Paolo Salucci

In my last post, I talked about the idea of warp drive and whether it might one day be possible. Today I’ll talk about another faster-than-light trick: wormholes.

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Alcubierre Gives us an Update on his Ideas About Warp Drives

The Enterprise using warp drive, as seen in Star Trek Beyond. Credit: Paramount Pictures

If you want a galaxy-spanning science fiction epic, you’re going to need faster than light travel. The alternative is taking decades or centuries to reach an alien star system, which isn’t nearly as much fun. So, you start with some wild scientific idea, add a bit of technobabble, and poof! Quam Celerrime ad Astra. Everything from wormholes to hyperspace has been used in sci-fi, but perhaps the best known FTL trope is warp drive.

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What's the Connection Between Stellar-Mass Black Holes and Dark Matter?

Artist view of a black hole in the middle of solar system. Credit: Petr Kratochvil/PublicDomainPictures CC0

Imagine you are a neutron star. You’re happily floating in space, too old to fuse nuclei in your core anymore, but the quantum pressure of your neutrons and quarks easily keeps you from collapsing under your own weight. You look forward to a long stellar retirement of gradually cooling down. Then one day you are struck by a tiny black hole. This black hole only has the mass of an asteroid, but it causes you to become unstable. Gravity crushes you as the black hole consumes you from the inside out. Before you know it, you’ve become a black hole.

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Almost all High-Energy Neutrinos Come From Quasars

The IceCube Neutrino Observatory at the South Pole. It detected neutrinos and helped astronomers trace them to blazars. Credit: Emanuel Jacobi/NSF.
The IceCube Neutrino Observatory at the South Pole. It detected neutrinos and helped astronomers trace them to blazars. Credit: Emanuel Jacobi/NSF.

Buried under the ice at the South Pole is a neutrino observatory called IceCube. Every now and then IceCube will detect a particularly high-energy neutrino from space. Some of them are so high energy we aren’t entirely sure what causes them. But a new article points to quasars as the culprit.

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