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Questions tagged [collision]

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Does the Final-Parsec problem apply to stellar collisions?

The final parsec problem describes the difficulty of two blackholes merging with one another when their distances reach ~3.2 light years apart. Does this also then apply to stellar collisions, perhaps ...
Shawn Lim's user avatar
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9 votes
1 answer
2k views

Had Earth lost the Moon early, would we be able to determine it once had a companion?

Despite the Solar System looking quite stable, clockwork-like on human timescales, to such a degree the movement of its members is used to track time and make calendars since antiquity, it is pretty ...
ksousa's user avatar
  • 1,171
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
11 votes
1 answer
5k views

Why did Theia create only one moon if it struck Earth?

If I dropped a heavy ball into some magma it would splash all over the place. So why would Theia create only one large drop of liquid (the moon) and if it impacted the Earths mantle (Bits of Theia ...
user avatar
2 votes
1 answer
124 views

Black hole collision

In a situation where 2 black holes are close to colliding, but do not collide, can one black hole free/steal matter from the other in passing if the event horizons brush?
Shaun Eric Ewing's user avatar
11 votes
2 answers
5k views

What would happen if Venus and Earth collided?

The first thing we would need to consider is that Earth has already been hit by a protoplanet half its size 4.5 billion years ago, meaning the Earth may have a chance of staying intact after the ...
user avatar
2 votes
2 answers
178 views

Will the Milky Way galaxy revolve around the Andromeda galaxy or vice versa?

As all of you know, in the Milky Way galaxy, the Solar System revolves around the Milky Way to complete the Galactic year (because we have the supper massive black hole in our Milky Way galaxy) then ...
Pash0002's user avatar
-2 votes
1 answer
96 views

What if a magically indestructible human-sized rocky meteor hit the United States at 10% the speed of light? [closed]

Let's say that it hits in the exact center and is somehow also incompressible and doesn't slow down upon entering the atmosphere.
Arctic's user avatar
  • 7
8 votes
2 answers
954 views

Does the barycenter of an n-body system remain constant during collisions?

I am developing an n-body simulation software which simulates collisions. Most of these have a stationary frame of reference, meaning that orbiting objects may eventually move off the screen. To ...
WarpPrime's user avatar
  • 6,673
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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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
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7 votes
1 answer
3k views

Is it possible for the Milky Way and Andromeda to get ejected upon colliding instead of merging?

The Milky Way and Andromeda are destined to collide and merge within the next 4-5 billion years, but I feel like there could be a chance that instead of merging, they could just eject each other. I ...
Prince Pugs's user avatar
5 votes
4 answers
307 views

If two fast asteroids collided, would the temperature and pressure be high enough to cause nuclear fusion?

Some near earth objects travel with speeds of dozens of kilometers per second. Would a head-on collision between two of them create suitable conditions for nuclear fusion?
2080's user avatar
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2 votes
0 answers
31 views

Question about plasma parameter

As we know, the deflection angle in strongly ionized plasma can be written as $$ \tan \frac{\theta}{2} = \frac{l_0}{l}, $$ where $\theta$ is the deflection angle, $l_0$ is the impact parameter when $\...
Sung's user avatar
  • 21
6 votes
1 answer
901 views

Why didn't Kessler Syndrome prevent planet formation?

In 1978, Donald Kessler proposed that space pollution in orbit around the Earth could enter a collisional cascading state. This means debris would collide with satellites, generating more debris, ...
Connor Garcia's user avatar
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0 votes
2 answers
219 views

Comet Bernardinelli-Bernstein; could it be a "planet-killer" and what could prevent it from getting close to us?

The huge "mega" comet C/2014 UN271 (Bernardinelli–Bernstein) 80 miles wide is coming towards Earth from the edge of our Solar System. It is supposed to only get to the middle of our Solar ...
Peter U's user avatar
  • 1,619
2 votes
3 answers
411 views

How do rocky planet break up? Would they fragment into "a gazillion" rocky pieces pieces, or crack open like an egg?

I remember seeing Star Wars, where Darth Vader shoots a superb laser (Death Star) to obliterate a populated planet, Alderaan (how inhumane). The problem is, the planet cracked into a gazillion rocky ...
Sage of Seven Paths's user avatar
2 votes
2 answers
173 views

What would be the product between the collision of a white dwarf and a main sequence star?

Would this ever happen? If it would, what kind of star/supernova would this create? Does it depend on the mass of the main sequence star?
Jack the Ranger's user avatar
1 vote
0 answers
56 views

How would it possible to Andromeda collide with Milky way? [duplicate]

If galaxies are moving away from each other how is it possible to Andromeda collide with Milky Way?
simpson's user avatar
  • 11
1 vote
0 answers
46 views

Is the Condor Galaxy (NGC 6872) the result of a non-collision galaxy interaction?

All the interacting galaxies that I can find are of collisions, I'm trying to find an example of a fly-by galaxy interaction. Is the Condor Galaxy an example of one? Wikipedia's NGC 6872; Possible ...
MiscellaneousUser's user avatar
2 votes
2 answers
191 views

Any results from the probe that has been crashed into an asteroid once?

About two or three years ago I think a probe whose name I forgot has been crashed into an asteroid at high speed to see what would happen if we tried to collide something with an asteroid on Earth ...
John's user avatar
  • 1,538
4 votes
1 answer
601 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
  • 30.8k
0 votes
2 answers
110 views

Why collisions between earth orbiting satelites do occur?

According to Kepler laws all earth orbiting satellites should have the same velocity. So how can they collide?
JCRCAN's user avatar
  • 31
2 votes
2 answers
163 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
3 votes
0 answers
274 views

Other side of Earth when the Dinosaur-killer struck

When the (Chicxulub) asteroid hit Yucatan, what was it like in the minutes, days and weeks afterward on distant locations on Earth? Related How loud was the asteroid that killed the dinosaurs?
stretch's user avatar
  • 1,785
5 votes
1 answer
416 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
  • 6,673
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
3 votes
1 answer
319 views

What would happen to the Sun's evolution if it collided with another yellow dwarf?

How would the Sun evolve if it collided with another G-type main sequence star, perhaps a more massive one like Alpha Cen A? Since its mass would then be above the Chandrasekhar limit, could it ...
Greenhorn's user avatar
  • 293
1 vote
1 answer
201 views

How much mass would have to be added to the Sun to significantly alter any of its characteristics?

While this might at first sound like an XKCD What If? question, let's proceed with it because astronomical objects do occasionally merge. How much mass would have to be added to the Sun to ...
WarpPrime's user avatar
  • 6,673
1 vote
0 answers
85 views

Will the United States Presidential Election (day asteroid) be back soon?

My google news feed is awash with mono-themed articles, including a near Earth asteroid that passed by around election day 2020 in the US. We can all hope that neither will lead to an extinction level ...
uhoh's user avatar
  • 30.8k
9 votes
2 answers
592 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
0 votes
1 answer
211 views

Can two singularities combine into one? [duplicate]

We know that black holes can collide and merge, but if they each have a singularity at the core, how can the two singularities merge and become one? Wouldn't the mere fact of a second singularity in ...
Jack Alterman's user avatar
3 votes
2 answers
122 views

Small changes to Earth's orbit caused by a large impact on the Moon

Is there any scenario where a large impactor striking the far side of the Moon would perturb the Earth's orbit enough to reduce the distance from the Earth to the Sun and still remain within the ...
l.lyons's user avatar
  • 39
2 votes
0 answers
50 views

How common is it for large objects (few kilometers wide) in a young protoplanetary disk or debris disk to collide with one another?

If enough time has passed for gravitational forces to allow the formation of planetesimals(proto-planets) in orbit around the proto-star, how likely is it that two of them would collide with one ...
Ammanuel's user avatar
  • 359
6 votes
1 answer
387 views

How frequently are other planets in the Solar system hit by meteorites?

How frequently are other planets in the Solar system hit by meteorites? For example, is the rate per unit area about the same?
Pranay's user avatar
  • 783
1 vote
1 answer
93 views

Impact verses vacuum

How do asteroids, comets and other stuff stay together when colliding in the empty vacuum of space, when they are made up of non-sticky substances like rock? My understanding is that the force of ...
John's user avatar
  • 207
6 votes
1 answer
269 views

Black hole collision animation: What are these extrusions?

In this video uploaded by LIGO Lab Caltech, two inspiraling black holes are depicted. The video's description explains what is shown and can be summarized by: The colored surface is the space of ...
BMF's user avatar
  • 262
7 votes
1 answer
387 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
1 vote
0 answers
135 views

How big a rock can hit the sun and it not matter? [duplicate]

If a rock the size of Oumuamua were to crash into the sun — assume central collision — would it materially affect the sun’s behaviour? Would unaided humans (rather than sun-tastic special telescopes) ...
jdaw1's user avatar
  • 569
2 votes
0 answers
42 views

Would the WISE Survey pick up a large planetary collisions like Theia-Earth? And from how far?

WISE or Wide-Field Infrared Survey Explorer Large body collisions are obviously, very very rare, locally speaking, and with stars, often spiraling inwards not direct collisions. I know that stellar ...
userLTK's user avatar
  • 24.1k
-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
0 votes
1 answer
124 views

Latest Planet Collision 2019 [closed]

Scientist says that during the course of their billions of years, the planets collied with each other in the past. My question is: is there any latest or recent planetary collision in recent times?
roblox prisonlife's user avatar
7 votes
1 answer
819 views

Head on collision of two black holes [duplicate]

Inspired by If two black hole event horizons overlap (touch) can they ever separate again?, I was wondering what would happen if two black holes collided into each other in a head-on collision. In ...
KGlasier's user avatar
  • 173
5 votes
1 answer
235 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
  • 30.8k
1 vote
1 answer
184 views

When a rogue brown dwarf star hits a white dwarf star, will the collision at most cause a nova? [closed]

When a rogue brown dwarf star hits a white dwarf star, will the collision at most cause a nova? Or can the explosion be heavier?
Mike Andrews'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
4 votes
2 answers
177 views

Could two stars collide without a resultant explosion?

Are there any scenarios in which two stars could collide, and simply fuse without triggering a supernova. Maybe a mid-sized star slowly spiraling in together with a smaller star? It seems like any ...
Curious Layman's user avatar
2 votes
0 answers
56 views

What are the odds for any two bodies to collide during the milky way-Andromeda collision? [duplicate]

When the two main galaxies of the local group will collide, it is very unlikely for stars to collide with another, but how unlikely is it in the initial collision? And over the whole merging process?
Speedphoenix's user avatar
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
  • 30.8k
1 vote
3 answers
129 views

The expansion of the universe and how stars and galaxies still collide

How can it be that all galaxies and stars are moving away from each other yet they still collide? From what I have researched it as an open universe (or many open universes) yet the idea of stars and ...
user avatar