The near-vacuum extending between the planets and stars, containing small amounts of gas and dust. Also called outer space to refer to the physical universe beyond the Earth's atmosphere.
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3k views
How can a black hole produce sound?
I was reading this article from NASA -- it's NASA -- and literally found myself perplexed. The article describes the discovery that black holes emit a "note" that has physical ramifications on the ...
19
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1answer
707 views
Why does it take so long to get to the ISS?
I don't understand why when first launched Space X's Dragon capsule had to orbit the Earth many times in order to match up with the ISS? Was this purely to match it's speed, or to get closer (as in ...
17
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7answers
737 views
What grounds the difference between space and time?
We experience space and time very differently. From the point of view of physics, what fundamentally grounds this difference?
Dimensionality (the fact that there are three spatial dimensions but only ...
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5answers
5k views
How long does it take to travel 36 light years with tolerable acceleration and deceleration?
The recent discovery of HD85512b only 36 light years from Earth has promising attributes to harbor life. Assuming we want to travel there, we cannot instantaneously jump to light speed, (StarTrek ...
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2answers
2k views
How does space affect the human body (no space suit, no space craft)
How does "outer space" affect the human body? Some movies show it as the body exploding, imploding or even freezing solid.
I know space is essentially a vacuum with 0 pressure and the dispersion of ...
13
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2answers
1k views
What is the possibility of a railgun assisted orbital launch?
Basic facts: The world's deepest mine is 2.4 miles deep. Railguns can acheive a muzzle velocity of a projectile on the order of 7.5 km/s. The Earth's escape velocity is 11.2 km/s.
It seems to me ...
11
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2answers
268 views
Why were space physicists wrong about the location of the heliopause?
The heliopause is now estimated to be something around 100 AU (1 AU = Astronomical unit = about the earth sun distance). See the wikipedia article:
http://en.wikipedia.org/wiki/Heliosphere
From ...
11
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3answers
895 views
A water drop in vacuum
Let's imagine the following situation:
At an initial moment $t=0$, a large water drop with diameter for example $D=10\ \text{cm}$ is placed in deep space (Say an astronaut is experimenting). Let's ...
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13answers
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What are the mechanics by which Time Dilation and Length Contraction occur?
What are the mechanics of time dilation and length contraction? Going beyond the mathematical equations involving light and the "speed limit of the universe", what is observed is merely a phenomenon ...
10
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3answers
121 views
Why are spacecraft made to “spin” after launch?
At some point after launch, usually just before or after separation from the last booster stage, spacecraft are often made to "spin" (about the axis of their trajectory)? See e.g this You Tube video. ...
10
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2answers
3k views
Why can there be fire in space while there is no oxygen?
The sun is made of fire but fire needs oxygen right? So..
Why can there be flames in space, while there's no oxygen?
Same idea as with the rocket engines of the spaceship, which also produce fire ...
10
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1answer
131 views
How long will our artifacts last in moon & space?
Given all the different space probes and equipment that have been either launched into space or lying on the moon. How long will they last before they get decayed into dust or some unrecognizable ...
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6answers
982 views
Does anything exist in the intergalactic space?
I am a part time physics enthusiast and I seldom wonder about the intergalactic space. First, it is my perception that all(almost all) the objects in the universe are organized in the forms of ...
9
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1answer
185 views
How vacuous is intergalactic space?
You often hear intergalactic space is an example for a very good vacuum. But how vacuos is space between galaxy clusters and inside a huge void structure? Are there papers quoting a ...
9
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3answers
225 views
Explosion in space
I'm curious about what happens if an explosive substance detonates in space. On Earth, I guess a good chunk of the energy released is carried away by shock waves in the atmosphere. But in space, the ...
9
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1answer
288 views
Laptops in space
I was reading an article regarding the Shuttle's GPCs and how they stack up against commercially-made hardware on http://www.nasa.gov/mission_pages/shuttle/flyout/flyfeature_shuttlecomputers.html and ...
8
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5answers
2k views
If I take a bottle of air into space, and open it, where does it go?
It seems to me that space doesn't have any/much air, and if my bottle is full of air, when I open it, where does the air go?
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3answers
673 views
Can black holes actually merge?
If time stops at the event horizon, can we ever detect two black holes merging? In other words, if you are a short distance away, would you encounter a spherically symmetric gravitational field, or a ...
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2answers
442 views
What does the sky look like to human eyes from orbit?
There are numerous pictures, obviously, of the blackness of space from the shuttle, the space station, and even the moon. But they all suffer from being from the perspective of a camera, which is not ...
6
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3answers
207 views
Why Can We Observe Space Curvature / Warping At All?
I don't understand why we are able to see and measure curvature / warping of space at all.
Space as I understand it determines distances between objects, so if space were "compressed" or warped, ...
6
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1answer
561 views
What happened to Apollo's Saturn-third-stage rockets?
I read recently the original Apollo 11 press release and it mentions that the Saturn V's third stage (used for Trans-Lunar Injection) was deployed into a solar orbit of some kind:
I know that on ...
6
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1answer
203 views
Is there a “map” of the interplanetary transport network?
To my understanding, the idea behind the interplanetary transport network is that areas near heavy objects and their Lagrange points are accesible with comparatively little energy, for example one ...
6
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2answers
131 views
What are the limitations of performing music in space?
Canadian astronaut Chris Hadfield's song Space Oddity is making news around the world today. It makes me wonder: What are the limitations of performing music in space? Clearly, there is no point to ...
6
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4answers
181 views
Direct exposure to the vacuum of space
I was watching a few sci-fi movies and was wondering the real science explaining what would happen if you were to be subject to the conditions of outerspace.
I read the wikipedia article on space ...
6
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3answers
292 views
Getting back out of an Alcubierre warp bubble
Does the theory on paper provide a way for hypothetical travelers to get back out of the bubble that has gotten them close to their distant destination by compressing all the space in front of them ...
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4answers
718 views
Why can't a spaceship accelerate for ever? Since there is no friction in space
I have seen many answers like: because we don't have infinite energy, because of gravity, because it is impossible, because of physics.
But they don't really answer my question.. I mean if there is ...
5
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2answers
377 views
What's the difference between space and time?
I'm having a hard time understanding how changing space means changing time. In books I've read people are saying "space and time" or "space-time" but never explain what the difference is between the ...
5
votes
3answers
281 views
Would a fast inter-stellar spaceship benefit from an aerodynamic shape?
Some (generous) assumptions:
We have a spaceship that can reach a reasonable fraction of light speed.
The ship is able to withstand the high energies of matter impacting at that speed.
Given the ...
5
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3answers
445 views
Will a machine or a technique ever be possible that allows gravity in space?
And I ask out of pure curiosity. I know there is the "Vomit Comet" that allows for a non-gravity 'simulation' (for lack of a better word) on Earth, and I was thinking about if there would be a way to ...
5
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2answers
211 views
What is the largest sphere of liquid water that could exist in space held together under it's own gravity? [duplicate]
What is the largest theoretical sphere of liquid water that could exist in space held together under it's own gravity? I've always wondered if a planet the size of earth could exist as a single volume ...
5
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3answers
767 views
How do they produce air on the ISS?
How do they provide air on the ISS? I know it is produced by electrolysis but is that all they breathe, hydrogen and oxygen? The air here on Earth contains other things like nitrogen. Do the people ...
5
votes
2answers
779 views
Escape Velocity of Asteriod 243 Ida
I was reading about this asteroid (apparently, it has a moon, isn't that awesome?) and I started thinking about if I was on this asteroid, and I jumped, would I fall off?
It's been a while since I ...
5
votes
5answers
384 views
Why can't airplanes just keep going up? [duplicate]
Possible Duplicate:
Why do space crafts take off with rockets instead of just ascending like an aircraft until they reach space?
Ignoring that the engines only work in air, so say its a ...
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votes
5answers
629 views
What would ACTUALLY happen to a person jettisoned into space?
[insert obligatory statement of my lack of knowledge in physics]
Alright, so we have all seen the movies where someone gets blasted out of the airlock on their starship, or their suit decompresses ...
5
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3answers
318 views
An electromagnetic space elevator?
If you surround the equator with a continuous Niobium Tin superconductor ring, and ran somewhere near but less than the maximum current density through, the magnetic field of the Earth would support ...
5
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8answers
2k views
Definition of “direction”
Is there an actual definition of "direction" (that is, spatial direction) in physics, or is it just one of those terms that's left undefined? In physics textbooks it's always just taken for granted ...
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votes
3answers
81 views
What causes the permittivity and permeability of vacuum?
When light travels through a material, it gets "slowed down" (at least its net speed decreases). The atoms in the material "disturb" the light in some way which causes it to make stops on its path. ...
4
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2answers
190 views
In a spaceship, if a vessel suddently stops will an object inside the vessel keep going?
My question is a 2 part question.
First if a vessel in space is going very fast and suddently stops (maybe it is not possible but that is not the point) will things/humans inside the vessel keep ...
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5answers
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Gravity on the International Space Station
We created a table in my physics class which contained the strength of gravity on different planet and objects in space. At altitude 0(earth), the gravitational strength is 100%. On the moon at ...
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2answers
279 views
Would a sneeze by a cosmonaut in a spacesuit affect his movement?
Naive question; feel free to shoot me down
It is a truism that any motion in space would continue indefinitely unless it is opposed by an external force. If a cosmonaut were to sneeze within his/her ...
4
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2answers
828 views
“Artificial gravity” on a rotating space stations
There have been a lot of sci-fi shows recently using the "rotating space station" explanation for gravity on space stations.
After watching these videos:
...
4
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3answers
156 views
Microgravity: how powerful is an astronaut
In 2008, NASA astronaut Clayton Anderson tossed a 635-kg tank of ammonia coolant overboard from the International Space Station (ISS). Subsequently the tank burned up in earth atmosphere as planned.
...
4
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2answers
444 views
“Space” in General Relativity and “vacuum” in Standard Model, is it the same thing?
And expansion of space is equal to expansion of vacuum?
4
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2answers
83 views
How hot would space feel?
I read that the temperature of the space around the earth can vary greatly depending on whether or not it is in direct sunlight. Space, however, is not very dense, so I imagine that heat would not ...
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3answers
298 views
What Problems for 50 year space probe to Alpha Centauri?
I'm thinking speculatively. NASA is doing experiment with ion thrust tech. Assuming, that inside the next 5 years, we could create a probe which would take on the order of 30 to 50 years to reach ...
4
votes
2answers
244 views
Sum total distance of electrons on a spherical surface
What is the sum total distance between every possible pair of point charges when there are n point charges on a spherical surface?
All point charges can only and are located on the infinitesimal ...
4
votes
5answers
272 views
Does a interstellar spacecraft traveling at relativistic velocity require continous thrust to maintain velocity?
Assuming completely empty space, does a spacecraft traveling at 0.5 C require continuous thrust to avoid deceleration?
If the spacecraft is traveling at 0.5 C, does it's relativistic mass act upon ...
4
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2answers
98 views
What is the fastest a spacecraft can get using gravity-assist?
Assuming normal spacecraft and space objects (no neutron stars, black holes, etc). To what speed can a spacecraft accelerate using gravity-assist?
For example, if a spacecraft is moving at ...
4
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2answers
149 views
Is a semi-Euclidean space possible?
Does exists a geometry (3d for example) which is Euclidean in 2 dimensions (x and y coordinates) and non-Euclidean when the third dimension (z) is taken into account? In other words a space where it ...
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2answers
256 views
Why model space with real numbers?
Are there any good papers discussing why we use $\mathbb{R}^{3}$as a model for space? More specifically are there any that explain why we don't use other number systems such as extensions of the real ...
