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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How light years is measured.?

How light years are measured. Once i remember the distance between earth and moon are measured by light which travels and comeback and by the delay the distance is calculated.. But how light years are ...
2
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1answer
1k views

Would a high-explosive in a vacuum be less harmful?

Putting aside shrapnel effects, I believe that high-explosives cause damage by producing a shockwave. How do shockwaves work in space? I've managed to convince myself that a high-explosive shockwave ...
4
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2answers
404 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 ...
10
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1answer
11k 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 ...
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4answers
339 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. ...
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8answers
7k 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 ...
3
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1answer
397 views

Know altitude and speed of an object in orbit, with true anomaly

I'm quite stuck with this problem. I know that I have an object in orbit. I know the eccentricity of that orbit, as well as the semi-major axis of the orbit. Giving a true anomaly, how do I find ...
14
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15answers
2k views

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 ...
3
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1answer
106 views

Jupiter: Zonal Jets in opposite directions

I recently read that the Great Red Spot arises from the shear instability of zonal flow from zonal jets travelling in opposite directions. Is there any reason why such zonal jets travel in opposite ...
10
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1answer
628 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 ...
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3answers
10k 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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0answers
109 views

Faster than light communication [duplicate]

Possible Duplicate: Is it possible for information to be transmitted faster than light? Suppose you have a very long rod, both ends are in space and the rod is 100 light years long. If you ...
2
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1answer
230 views

Is rocket propellant meaningfully a form of “space junk”

I imagine that most people are familiar with the concept of space junk (or space debris), which is a hazard to space exploration that grows with every item that humans leave in space. Wikipedia lists ...
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2answers
179 views

Weightlessness and falling sideways

In Season 2, ep 4 of Star talk Radio, host Neil Tyson is talking about the international space station. He mentions that the space station is in a low earth orbit and is falling along the curvature of ...
10
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1answer
370 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 ...
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4answers
10k views

If there is no gravity on the moon why is the american flag waving?

If there is no gravity on the moon, how could this flag be flapping in the wind? http://www.stumbleupon.com/su/2wD6eg/hea-www.harvard.edu/~fine/images/desktops/Armstrong.jpg
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3answers
907 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 ...
2
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2answers
2k views

In summer are the upper storey flats more hot or the lower storey flats?

I have often heard neighbours talking things like in a multi storied apartment, the upper flats are more hot in summer then lower flats (or vice versa?) and similarly for some comparison in winter? ...
8
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4answers
289 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 ...
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2answers
1k 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 ...
3
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3answers
458 views

How would steel degrade in space

If there is a steel plate floating in space, for ever, within the solar system, how is it going to degrade? Of course without oxygen it is not going to oxidize (rust), but how are cosmic rays, UV ...
2
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1answer
3k views

What are the temperatures of objects in Low Earth Orbit (LEO)?

What is the temperature of objects in Low Earth Orbit? Consider LEO to be 600km to 800km.
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3answers
598 views

How would you move without gravity?

I'm wondering how would you move without gravity? You would still have air pressure at 1Atm. Would you "swim" in the air or would you have do something else?
2
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1answer
277 views

Heat reflection on distant planets

I was watching a documentary last night on the first planet discovered outside our solar system. The first one apparently is a giant gas planet that orbits very close to its sun over a very fast ...
4
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1answer
193 views

The most stable metal for radioactive environment

Could you suggest which metal/alloy shows the least activation & better long-term stability for space (LEO, inside Van allen belts, deep space) applications? Or stability of construction ...
5
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2answers
1k 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 ...
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2answers
543 views

what about there is no time, only space [closed]

what about a theory where no time exists, only discrete space, steady states and occasion chains. what would speak against this? ;-)
3
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1answer
780 views

Effects on a tree exposed to the vacuum of Space

My wife's kindergarten class asked, "What would happen to a tree planted on the moon?" Aside from the obvious that it would die from lack of water/air, what physical effects would happen to a tree ...
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3answers
1k views

How do spacecraft cameras work?

When I look at pictures taken by a modern spacecraft (like that one showing the surface of Titan: and taken by Cassini) I kinda understand how they might be produced. There might be some kind of ...
4
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2answers
1k 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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7answers
3k views

What properties do you need for building a tower?

When I was a boy I used to daydream about building a tower so tall that the top of it would stick out of the top of Earth's atmosphere project into near space. There would perhaps be a zero gravity ...
5
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3answers
655 views

Will a machine or a technique ever be possible that allows artificial gravity in interplanetary space?

Will a machine or a technique ever be possible that allows artificial gravity in interplanetary space? And I ask out of pure curiosity. I know there is the "Vomit Comet" that allows for a non-gravity ...
0
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3answers
110 views

Is there a chance for Earth to have an additional satellite someday?

I am just an space enthusiast and not a physics professional so pardon me if this is not the right place to ask. As title says, is there a chance for our Earth to have additional satellite(s) like our ...
3
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1answer
364 views

What are the coloured bands in this “Pale Blue Dot” picture?

You can see Earth in the right most band in this image: What are these bands doing in space?! Can somebody please explain the coloured bands in this image?
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6answers
6k views

Does vacuum (empty space) exist? [closed]

Added: 5 times down vote for now! Down voter is this religion or physics, please try to explain your decision. I'm confused about this. In physics we know for a vacuum, but I think that there is a ...
3
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3answers
208 views

Object docking in Space

How do objects dock in space? There's a recent piece of news that Keppler would dock to the ISS sometime this week. I want to know the operational aspects of it - considering the velocity of the ...
0
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3answers
366 views

How does solar activity affect the ISS?

Currently the sun is launching some intense solar flares. http://www.guardian.co.uk/science/2011/feb/17/solar-flares-northern-lights-uk Th article I've linked also mentions how a "coronal mass ...
2
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5answers
541 views

what are dimensions?

First, discrete examples. In a computer screen I can specify any "2D" point with just one single number (pixel order starting count from first at upper left, and going on, left2right and up2down ...
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1answer
482 views

History of Man Acquired knowledge of solar system [closed]

I know the basics of solar system like how earth moves around sun, and that we have so many planets, elliptical orbit of earth, and how far is sun from earth etc etc. I want to take a step back and ...
3
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5answers
672 views

Why is everything floating in space so cold?

Of course there is pretty hot stuff too. For example Suns. But isn't the vacuum of space the perfect containment for heat? And shouldn't the rare collision with particles even heat up an object that ...
12
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2answers
307 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 ...
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3answers
3k views

Visualizing Electromagnetic Waves in 3D Space [closed]

I did one module of physics for my GCSE one year ago which taught me about transverse EM waves & the EM spectrum, but since then, I do not understand how a wave would move in 3D space. Can someone ...
7
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5answers
1k 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 ...
2
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3answers
885 views

If the earth left the solar system for interstellar space. How long would it take for atmosphere to freeze

If the earth left the solar system for some reason. Assuming its moving at the same velocity it's currently exhibiting. How long would it take for the atmosphere to freeze. Would we get methane ...
6
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2answers
575 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?
2
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0answers
318 views

What is the name of the physical space enveloping all universes? [closed]

Please excuse my question, as i don't come from a physics background, but i was really wondering. Assuming we are in one of numerous universes which all have physical dimensions: What is the name of ...
11
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3answers
1k 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 ...
2
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1answer
309 views

Distinguishing mechanical systems from general dynamical systems

[Remark: I admit that my first attempt on What makes a space a real space? was rather ill-posed and led to some confusion. Sorry for that, but please give me a second try. Part of the confusion arose ...
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1answer
261 views

What makes a space a real space?

By "real space" I mean a space in which physical particles move. Consider a color sphere and let a bunch of objects "move" on its surface. "Move" means "change colors". Let there be some rules ...
3
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2answers
624 views

What is an “Idea” in terms of time space and matter? [closed]

If the physical world we know is made of matter stretched in time and space and some forces affecting it, what would be an Idea, pure Information or something similar. Does those things don't exist ...