121
votes
A starship is traveling at 0.9c and collides with a small rock. Will it leave a clean hole through, or will more happen?
@Hobbes answered this in a comment.
Your final guess
Will it collide with enough energy to initiate fusion with the atoms of the hull?
is correct.
See the first XKCD What-If comic, "Relativistic ...
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91
votes
Is the SpaceX Falcon Heavy payload (a Tesla car) space junk?
No, because it is not in Earth orbit
First the payload does have a purpose: it is a boilerplate, and those have a purpose, namely to "test various configurations and basic size, load, and handling ...
- 1,829
68
votes
Why are there mountains/mounds in the centre of craters on the lunar surface?
Oh, I can answer this one. In my structural geology class, we breezed over a few paragraphs on the tectonics of impact craters, but it was in the textbook, and, being space-related, I was intrigued.
...
- 10.6k
63
votes
Is the SpaceX Falcon Heavy payload (a Tesla car) space junk?
Yes, it's space junk: after about 6 hours, the second stage will stop working and there will be no way to change the trajectory of stage and payload. So it's a non-functional satellite, i.e. junk. An ...
- 124k
53
votes
Does NASA have an end-of-the-world policy?
First off, large life-ending asteroid impacts are very rare as there aren't many of them out there and we've found almost all of them:
Looking at the 'continent' and 'global catastrophe' areas of ...
- 2,496
50
votes
BBC: "A rocket launched by Elon Musk's space exploration company is on course to crash into the Moon and explode." Will it really explode?
It depends on how you define "explosion". Most generally, it merely describes something that breaks into pieces violently. Astronomical impact events can generate explosions simply from ...
- 3,587
44
votes
Is the SpaceX Falcon Heavy payload (a Tesla car) space junk?
Footnotes:
${}^1$ That the term "Space Junk" (as used in this answer and which is probably the right answer) has a different generally agreed meaning in spacecraft lingo than just plain "Junk" has ...
- 148k
35
votes
A starship is traveling at 0.9c and collides with a small rock. Will it leave a clean hole through, or will more happen?
I answer this question from a purely structural-mechanical point of view, i.e. not considering fusion as discussed in Dan Pichelman's answer.
Will it create a football sized hole through the ship ...
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32
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BBC: "A rocket launched by Elon Musk's space exploration company is on course to crash into the Moon and explode." Will it really explode?
I think it's worth looking at how much energy that rocket is going to be carrying. Plugging the 4 tonnes and 5000 mph figures into an Online calculator we find that the impact will carry close to 10 ...
- 421
27
votes
Accepted
If a Voyager crashes into something, would we know?
Most likely no.
Voyager downlink communication (via its radio link to NASA's Deep Space Network (DSN) is not continuous. You can check the contact schedule at this Voyager site. If everything looks ...
- 18.2k
26
votes
A starship is traveling at 0.9c and collides with a small rock. Will it leave a clean hole through, or will more happen?
Let us consider a 10 kg rock with a $0.1\,\mathrm{m}^2$ cross-sectional area. Further let’s assume that we are lucky and the rock passes only through one wall of the spaceship (say $3\,\mathrm{mm}$ of ...
- 19.3k
25
votes
Accepted
How did two satellites end up in almost the same orbit except moving in opposite directions?
How? Simple, because they launched into those orbits.
Why? Well, first, let me explain what their orbits actually are.
IRAS (13777) and GGSE-4 (2828) are both in high-inclination orbits, 70° and 99°...
- 10.6k
24
votes
Why not crash the ICPS into the Moon?
The upper stage for Apollo 8 through Apollo 12 were sent into heliocentric orbit. On the last five flights, Apollo 13 through Apollo 17, the upper stages were instead intentionally crashed into the ...
- 72.5k
21
votes
Accepted
Can a nuclear detonation on Moon destroy life on Earth?
Probably not. Just to give you an idea, lunar rocks hit the Earth on a somewhat regular basis. The power required to have a rock hit Earth is equivalent to that of making a 450 m crater. This comes ...
- 121k
21
votes
BBC: "In 2009 Prof McDowell & other astronomers performed an experiment in which a similar-sized rocket was crashed into the Moon." Really? Which one?
"2009 impact" would probably be when the LCROSS/LRO upper stage was crashed into a crater at the Moon's south pole. The LCROSS Centaur upper stage had a mass at impact of around 2300 kg; an ...
- 14.1k
19
votes
Is the SpaceX Falcon Heavy payload (a Tesla car) space junk?
It depends.
In the industry, the concern with space junk is whether or not certain objects are a navigational hazard. If the Falcon Heavy payload were on a collision course with an active spacecraft, ...
- 23.7k
19
votes
How many satellites can stay in a Lagrange point?
Lagrange points as I understand it are points in space between 2 objects where the gravitational pull between them is effectively equal.
A quick check of Wikipedia's Lagrangian point or any article ...
- 148k
16
votes
What would happen if an Earth-sized body encountered Jupiter?
If you saw the video of the Shoemaker-Levy collision you will see that although that was a collection of smaller objects, there is very much a collision, rather than a gas engulfing a solid.
Once the ...
- 13.6k
16
votes
Accepted
How can we avoid collisions when moving from one orbit to another?
Exactly the same way you avoid collisions when not altering orbit.
Altering your orbit does not significantly alter your risk of collisions, other than possibly moving you to a higher or lesser ...
14
votes
BBC: "A rocket launched by Elon Musk's space exploration company is on course to crash into the Moon and explode." Will it really explode?
Energy-wise, I'd call it an explosion
Kinetic energy (KE) = 1/2 mv2
The article quotes the mass at 4 tons, and the speed as 5,000 mph. That gives:
KE = 0.5 * 3628 kg * 2235 m/s * 2235 m/s = 9 ...
- 1,348
14
votes
Accepted
Have any bits of a space mission ever collided with a planet or large moon (not Earth) that was not a target of the mission?
Yes
https://scitechdaily.com/space-junk-just-crashed-into-the-far-side-of-the-moon-at-5800-mph/
A piece of space junk (China or spaceX) hit the far side of the moon
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13
votes
Why are there mountains/mounds in the centre of craters on the lunar surface?
It's actually a rebound effect that occurs with an impact forming a large crater. https://www.lpi.usra.edu/education/explore/shaping_the_planets/impact-cratering/ explains:
Central peaks – Peaks ...
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13
votes
Why are there mountains/mounds in the centre of craters on the lunar surface?
It might help to compare the crater formation to a drop impact:
It seems that rock can behave like a viscous mass if you hit it fast enough.
- 1,676
12
votes
Accepted
Would the one million people on Mars be killed by an impact equivalent to an Extinction Level Event on Earth
I would guess no. What makes the extinction level events so dangerous for us isn't the impact or the shockwave. A shockwave on Mars won't do much damage since the atmosphere is very thin anyway, and ...
- 4,595
12
votes
How likely is it that the Voyager spacecrafts haven't yet been damaged by micrometeoroids?
This is a great question, I'm no planetary scientist but I'll give a partial answer to get things started.
Interplanetary dust is ubiquitous in the solar system and interplanetary spacecraft including ...
- 148k
11
votes
Accepted
What impact would a pea size meteor have when it hits the ground?
Asteroids, Meteorites, and Comets has this to say:
Meteorites between the size of a grain of sand and about four inches
(10 cm) in diameter create a bright light trail and usually burn up in
...
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10
votes
Accepted
How might one approach using AI (convolutional neural network) to predict collisions in orbit?
As a data scientist with an interest in space stuff, I am well positioned to give an answer this question. I must confess I don't understand fully what is going on in this system from just the lecture ...
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10
votes
A starship is traveling at 0.9c and collides with a small rock. Will it leave a clean hole through, or will more happen?
Probably the spaceship is destroyed.
The big problem is that the energy of the rock-spaceship collision is large. So large that even if a trivial amount is deposited into the spaceship, the ship is ...
- 505
9
votes
Accepted
Is Starman/Roadster in any danger in the asteroid belt?
Is Starman/Roadster in any danger of asteroid belt?
Honestly? No.
The Asteroid belt does contain lots of asteroids. But this is deep space. These things are not close together in any sense.
Think ...
- 206
8
votes
Accepted
What would happen if an Earth-sized body encountered Jupiter?
I like the answers, but I'm going to give a brief intuitive answer in addition.
Would Jupiter engulf the object and make it stay at Jupiter's core?
reading the other question, which I'm sure you ...
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