Space and Astronomy Megathread (MERGED) - Part 1

Even if it doesn strike earth, I would think it hitting some satellites and causing a runaway collision disaster with a bunch of other satelites could be devastating for modern society. But Idk the chances of such an event.
 
Apophis seems to be the go-to asteroid for the doomsayer crowd. :cool: Several years ago, there was concern about a possible 2029 impact. It was soon determined, however, that this wouldn’t happen. But then there were additional concerns that the 2029 close encounter would alter Apophis’s orbit and could setup an impact in 2036. For this to happen, Apophis would have to make a precisely defined flyby in 2029 - through a so-called “gravitational keyhole.” And according to the best calculations, Apophis will miss the keyhole.

Yeah, this is old news. A 2029 or 2036 hit were ruled out years ago. It currently has a 1 in 150000 chance of hitting in 2068.
 
Even if it doesn strike earth, I would think it hitting some satellites and causing a runaway collision disaster with a bunch of other satelites could be devastating for modern society. But Idk the chances of such an event.

Hitting a satellite is extremely unlikely. The chances of hitting multiple satellites would be practically zero. There is a lot of space up there (even in Earth orbit) and satellites are small and far apart.
 
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This HDR image of the solar eclipse in 2017 was recently released for the first time, and it shows one of the most detailed depictions of a solar corona ever taken. Image credit: Sebastian Voltmer.



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There are fastballs, and then there are cosmic fastballs. Now it seems that the strongest arm in our galaxy might belong to a supermassive black hole that lives smack in the middle of the Milky Way.

Astronomers recently discovered a star whizzing out of the center of our galaxy at the seriously blinding speed of 6.4 million kph.

The star, which goes by the typically inscrutable name S5-HVS1, is currently about 29,000 light-years from Earth, streaking through the Grus, or Crane, constellation in the southern sky. It is headed for the darkest, loneliest depths of intergalactic space.

The runaway star was spotted by an international team of astronomers led by Ting Li of the Carnegie Observatories. They were using a telescope in Australia for a study known as the Southern Stellar Stream Spectroscopic Survey — the S5.

The star is about twice as massive as our own sun and ten times more luminous, according to Li.

Drawing on data from the European Space Agency’s Gaia spacecraft, which has charted the positions and motions of some 1.3 billion stars in the Milky Way, the astronomers traced the streaking star back to the galactic center.

That is the home of a black hole known as Sagittarius A*, a gravitational monster with the mass of 4 million suns.

The astronomers hypothesize that the runaway star was once part of a double-star system that came too close to the black hole. One of the pair fell in, and the other was sling-shotted away at hyperspeed.

The process, a three-body gravitational dance, was first predicted by Jack Hills, a theorist at Los Alamos National Laboratory, in 1988.

The dance with S5-HVS1 unfolded about 5 million years ago, according to Li and her team, which included Sergey Koposov of Carnegie Mellon University, lead author of a paper describing the results published Tuesday in the Monthly Notices of the Royal Astronomical Society.

The astronomers estimate that in about 100 million years the star will have exited the Milky Way entirely. It is yet another example of nature’s ability to mix things up — tossing comets from faraway stars into our solar system, and flinging ice, rock and who knows what else between the planets on asteroids.

Out there, drifting among the other galaxies of the Local Group, far from the crowded circumstances of its birth, the star called S5-HVS1 will exhaust its thermonuclear fuel in about 2 billion years, blow up and die, alone.

Like some people going off to college, say, some stars leave home and never come back.
 


This finding (if confirmed) indicates a larger maximum for a stellar mass black hole. Typically, they were thought to range between 5x and 20x the mass of the Sun. And LB-1 is reportedly 70x. :wow: Thus, the sensational headlines play up the “monster” description. But supermassive black holes (at the centers of galaxies) are hundreds of thousands to billions of times more massive that the Sun. Those are the true “monsters.”
 
I hate it when you find out the the colors of your favorite celestial object are false. :(
 

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