Philip Plait's Blog, page 24
July 23, 2021
The tallest mountain on a neutron star may be a fraction of a millimeter tall
The tallest mountain on Earth — measured from its base to its peak — is the volcano Mauna Kea at 10,200 meters (6.3 miles) high.
On a neutron star, the tallest mountain would be a millimeter high. Maybe as much as a centimeter.
That's according to new research done looking at how these tiny but ridiculously powerful objects work. It may seem a little esoteric to wonder how tall a mountain can be on the ultra-compact remnant of a massive star's core, but it turns out to have some pretty importa...
July 22, 2021
A disk of material around an alien planet may be forming moons as we watch
So far, astronomers have found nearly 4,500 exoplanets orbiting other stars. But, despite that large number, there has been no solid detection of an exomoon, a moon orbiting any of those planets* .
However, there’s intriguing evidence that a planet orbiting a nearby star may have the raw materials to build a moon, and one or more moons may be forming there right now. New (and extremely cool) observations confirm earlier ones that the planet is surrounded by a disk of dust with enough mass to ma...
July 21, 2021
Do you have to be a billionaire to ride a rocket to space? No, but it helps.
Yesterday, Jeff Bezos — the founder and CEO of Amazon, and, not incidentally, Blue Origin — took a ride into space along with three other people inside the capsule of a New Shepard rocket.
It was a suborbital flight, which means they essentially went straight up and then back down, reaching a height of over 107 km above Earth’s surface. That is higher than the generally accepted altitude of 80 km (50 miles) marking the edge of space, making the four passengers officially astronauts.
Much has b...
July 20, 2021
The sky is filled with rivers of darkness
Your eyes lie to you.
When you go outside on a crisp, clear night and look at the stars, it looks like they rule the sky, the only denizens of the black.
Oh, certainly, if you happen to see the Milky Way stretched out above you as well it looks fuzzy, like a stream of milk that gives our galaxy its name (and even gives us the very word galaxy). But that’s an illusion of sorts, the combined light of billions of individual stars too dim to see on their own. Even that just affirms the stellar pr...
July 19, 2021
A deep look at a nearby galaxy’s black hole reveals the launching point of intergalactic jets
The amazing Event Horizon Telescope has done it again: It has taken extraordinarily high-resolution images of the nearby galaxy Centaurus A, revealing twin beams of material shooting away from the supermassive black hole in its heart at a significant fraction of the speed of light.
The Event Horizon Telescope is actually many different telescopes around the world that can observe an object simultaneously, then have their data combined in a way that gives them the resolving power of a telescope ...
July 16, 2021
How are stars born? Absolutely gorgeously. See for yourself.
How are stars born?
After millennia of wondering, astronomers are now able to answer that question, at least to a large degree. Huge clouds of gas and dust in space collapse, and clumps of denser material form which then collapse more rapidly, their own gravity compressing them until they can ignite nuclear fusion in their cores.
A star is born.
But there are still a lot of questions to answer here, scads of details to fill in. And not just details but also big-picture questions. Literally.
...July 15, 2021
Mysterious bursts of radio pulses prefer a galaxy's loving arms
By looking at what neighborhoods they live in, astronomers are starting to get a better handle on mysterious, extremely short, and powerful flashes of energy called Fast Radio Bursts.
FRBs, for short, are pretty weird. They're intense but extremely short, lasting for a millisecond or so, and so powerful they can be detected at intergalactic distances; many are extremely far away. The first one was detected in 2001 but wasn't noticed until later, when astronomers looked at archived data. They st...
July 14, 2021
The ultimate fate of a nearby four-planet system: cosmic pinball, then game over
Bad news: Any potential aliens that live in the HR 8799 planetary system have only about 3 billion years to learn how to build starships before their planets are ejected into interstellar space when the star dies.
Good news: The planets are only 30-40 million years old so there are no aliens there anyway.
¯\_(ツ)_/¯
HR 8799 is a young nearby star, just 135 light years from Earth. The star is about 1.5 times the Sun's mass, making it brighter and hotter than the Sun. It's likely part of a small...
July 13, 2021
Mars 'copter Ingenuity still flying high, spots hazards for the Perseverance rover
Last week, engineers at the NASA/Caltech Jet Propulsion Laboratory let the Mars Ingenuity helicopter fly for the ninth time, an amazing achievement that means the semi-autonomous drone has now made four flights past its mission's nominal five. Images it took on this latest jaunt showed terrain ahead of the rover Perseverance's path, including marking some areas that would prove dangerous for the rover to tread.
The helicopter landed on Mars along with Perseverance, tucked underneath the two-ton...
July 12, 2021
Measuring the expansion of the Universe: Dying stars may be telling us we're doing it wrong.
How fast is the Universe expanding?
This is one of the most fundamental questions in cosmology (the study of the origin and behavior of the Universe), let alone science itself. We've known for a century that it's expanding; observations of distant galaxies show they are all moving away from us, which is what you'd expect to see if you're inside an expanding cosmos. As space itself expands it carries galaxies along with it, and the farther away they are the more rapidly they move*.
Thing is, wh...
