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Aki
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Is there anything such as antigravity?
Is there anything such as antigravity?
- Thread starter Aki
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In summary: Redshift is a measure of the distance to an object or source. It is a shift of the spectral lines of light from the object or source towards the red end of the visible spectrum.
- #2
Nereid
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Welcome to Physics Forums Aki!
It rather depends on what you mean by 'anti-gravity'.
In one sense, bouyancy could be thought of as anti-gravity.
If you are thinking of an analogy with electrical charges (like charges repel, unlike charge attract), or a bar magnet, then the answer is no; there is no experimental or observational result which suggests that there are forms of mass which can repel each other.
You might think that atoms of anti-matter would show anti-gravity? (for example, anti-hydrogen, made of an anti-proton and a positron, would 'fall up' in a vacuum tube here on Earth) Well, no; although this hasn't been observed yet (anti-hydrogen is very difficult to make!), the limited results on the gravitational effect of anti-matter are consistent with the theory - anti-matter 'falls down'.
It rather depends on what you mean by 'anti-gravity'.
In one sense, bouyancy could be thought of as anti-gravity.
If you are thinking of an analogy with electrical charges (like charges repel, unlike charge attract), or a bar magnet, then the answer is no; there is no experimental or observational result which suggests that there are forms of mass which can repel each other.
You might think that atoms of anti-matter would show anti-gravity? (for example, anti-hydrogen, made of an anti-proton and a positron, would 'fall up' in a vacuum tube here on Earth) Well, no; although this hasn't been observed yet (anti-hydrogen is very difficult to make!), the limited results on the gravitational effect of anti-matter are consistent with the theory - anti-matter 'falls down'.
- #3
geometer
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Special Relativity predicts a kind of anti-gravity. Special Relativity requires that the vacuum have a negative pressure equation of state, given this, a positive cosmological constant will act to cause a large scale repulsion.
- #4
Gonzolo
geometer said:
I think you mean General Relativity.
- #5
geometer
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oops - yes!
- #6
Mk
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An exotic form of matter would, in the spaceitme-is-a-sheet analogy be on top of a hill instead of in a little hole. How is there negative pressure in a vacuum?
- #7
Aki
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geometer said:
what is negative pressure? I've always had trouble understanding it
- #8
Nereid
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You might find this page, from Ned Wright's cosmology tutorial, helpful. If, after reading it, you still have questions (I hope that you do!), please come back and ask.Aki said:
- #9
Aki
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Nereid said:You might find this page, from Ned Wright's cosmology tutorial, helpful. If, after reading it, you still have questions (I hope that you do!), please come back and ask.
thanks for ths site. Um...I already have a question on the first sentence; "Recently two different groups have measured the apparent brightness of supernovae with redshifts near z = 1." What is that "z"?
- #10
Nereid
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redshift; z = (observed wavelength - 'source' wavelength)/('source' wavelength).Aki said:
http://www.wordiq.com/definition/Redshift
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1. What is antigravity?
Antigravity is a theoretical concept that refers to the ability for an object to repel or counteract the effects of gravity, resulting in the object floating or levitating.
2. Is antigravity real?
Currently, antigravity is not a proven scientific phenomenon and there is no known way to create it. However, there are ongoing research and experiments exploring the possibility of antigravity and its potential applications.
3. Can antigravity be used for space travel?
The idea of using antigravity for space travel has been explored in science fiction, but there is no evidence to suggest that it is possible. The laws of physics, specifically the law of conservation of energy, make it unlikely that antigravity will ever be a viable means of space travel.
4. How does antigravity work?
As mentioned earlier, antigravity is a theoretical concept and there is no known way to create it. However, some theories suggest that manipulating the gravitational force with advanced technology or harnessing the power of antimatter could potentially lead to the creation of antigravity.
5. Can antigravity exist on Earth?
As of now, there is no scientific evidence to suggest that antigravity exists on Earth. The Earth's gravitational pull is quite strong and would require an immense amount of energy to counteract. However, scientists continue to explore the possibility of creating artificial antigravity in controlled environments.
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