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Questions tagged [collision]

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30 votes
3 answers
5k views

What are the odds that the Sun hits another star?

The Sun moves around the Milky Way disk in the same direction as most of the other stars in our galaxy (prograde). But there are a number of older stars in the galactic halo that move in retrograde ...
Connor Garcia's user avatar
  • 16.3k
5 votes
1 answer
417 views

If two stars collide, what is the probability that they merge to form a single star?

After looking at What are the odds that the Sun hits another star? and answering it (crudely), now I'd like to ask the following: What is the probability that if two stars collide, their cores merge ...
WarpPrime's user avatar
  • 6,683
4 votes
1 answer
610 views

What is the difference between the terms collision and merger? How are they used differently in Astronomy?

We often hear of mergers of two stellar objects but we also sometimes talk about these or much smaller objects like planets or asteroids colliding. What is the actual differences between Astronomy and ...
uhoh's user avatar
  • 30.6k
27 votes
4 answers
3k views

Why did they decide to hit Dimorphos in the retrograde direction rather than prograde; was it a "coin-toss" or were there implications for observing?

CNN Space and Defense Correspondent Kristin Fisher does a really good job of summarizing the current state of the Double Asteroid Redirection Test early observational results for general public ...
uhoh's user avatar
  • 30.6k
21 votes
4 answers
6k views

What would happen if a small black hole fell into a star?

Let's say you created a cannon that can shoot small black holes and you shoot it at some star. Would the star just turn into a black hole silently? Or rather first destabilize and produce a last ...
Filip Sondej's user avatar
9 votes
2 answers
593 views

How likely are planets to form after neutron star collisions?

It is well known that planetary collisions can create moons orbiting the result of the merger if they happen in the correct way, and this is how the Earth's moon is believed to have been formed. See ...
Mr. Nichan's user avatar
7 votes
1 answer
1k views

What is Earth believed to have looked like before the collision with Theia?

Let's assume the moon was formed because Earth collided into Theia. (There are numerous other theories, but this one is the most widely accepted.) In that case, are there theories that address what ...
M. C.'s user avatar
  • 179
7 votes
1 answer
390 views

How much damage would collision with a similar mass primordial black hole do to earth?

All this talk of Planet 9 perhaps being a primordial black hole (PBH) made me wonder how dangerous a PBH collision with earth would really be. Specifically, if earth collided with a PBH of 1 earth ...
joseph.hainline's user avatar
5 votes
1 answer
239 views

What is the closest an asteroid or comet has passed the Sun and survived?

After SOHO began watching the Sun from space with its coronagraphs 24/7 it was discovered that there are comets passing very close to the Sun quite regularly, and while some are destroyed, some are ...
uhoh's user avatar
  • 30.6k
3 votes
0 answers
45 views

What does "Secondary reflection from Didymos may allow imaging of the night side of Dimorphos" mean? Why useful? Imaged from where?

@ConnorGarcia's "impactful" answer to Why did they decide to hit Dimorphos in the retrograde direction rather than prograde; was it a "coin-toss" or were there implications for ...
uhoh's user avatar
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3 votes
3 answers
1k views

What is the nature of "rock vapor" in this description of the formation of the Moon?

The NPR News item MacArthur Fellow And Planetary Scientist Sarah Stewart Discusses How The Moon Was Formed and audio podcast begins: Ari Shapiro, Host: Sarah Stewart likes to think about what happens ...
uhoh's user avatar
  • 30.6k
2 votes
2 answers
165 views

Could our Sun be the product of an ancient stellar collision?

The canonical model for the formation of the Solar System involves the gravitational collapse of a nebula into (perhaps) several stars across several light years. Is it possible that two or more of ...
Connor Garcia's user avatar
  • 16.3k
-2 votes
1 answer
202 views

From what distance will be able to see milky way and andromeda collision? [closed]

Considering that we would out of Milky Way, at what distance would a human will be able to see the collision with naked eye and and how fast would the galaxies appear to be approaching each other
Akash Singh's user avatar