Term
| How did we know that there are other planets in the universe. |
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Definition
Our sun is a very typical star. There are billions of others just like it out there.
If our star formed with a solar system around it then those other stars must have also formed with a solar system around them. |
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Term
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Definition
| Planets in other solar systems. |
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Term
| 5 Methods of finding Extrasolar planets (in order of importance according to me) |
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Definition
1. Radial velocity
2. Transit
3. Microlensing
4. Direct Observation
5. Circumsteller Disk |
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Term
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Definition
When a large planet orbits a star it moves the center of mass of the system out so that the star and the planet orbit the center of mass of the system instead of everything orbiting the star.
You can observe this as a wobble in the star. |
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Term
| Do you have to be able to see the planet to be able to identify a star with a planet around it using the radial velocity method? |
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Definition
No
If you see the star wobble it means there is a planet orbiting it. |
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Term
| When we find a star through the radial velocity method do we actually see the star wobble in the sky? |
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Definition
No, that would be too difficult to detect.
Instead we look for the Doppler effect: If we see a star changing frommred to blue to red again we know it is wobbling. |
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Term
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Definition
When a star moves away from us the light waves get streaches out and look red
When a star moves tword us the light waves get squashed and look blue |
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Definition
| When somethingnonly tells us part of the story. When one of theses methods only identifies curtain types of planets. |
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Term
| What Is the bias for the radial velocity method? |
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Definition
1. The larger the planet orbiting the star, the further the center of mass is from the center of the star and the wobble will look bigger.
2. The farther the planet is from the star the longer it takes for the planet to orbit and the star to wobble so it is difficult to detect.
The radial velocity method only finds large planets that are close to their suns |
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Term
| Why are there so many large planets so close to their suns? |
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Definition
| They can't have formed there. They must have moved there after forming. |
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Term
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Definition
| When a planet crosses in from of a star it dims the light coming from the star. The transite method looks for stars that get dim and then bright again. |
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| How often to planets transit across stars? |
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Definition
VERY rarely.
So we have to look at millions of stars to find one or two that have a planet transiting. |
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Term
| How can we use the transit method to not only find planets but also find the composition of the surface of the planets? |
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Definition
If we collect and image of the spectra as the planet passes in front of the star and subtract a spectrum image of the star alone we will be left with the spectrum of the planet.
(star+planet)-star=planet |
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Term
| What would we look for in the Spectrum of a planet to determine wheather life exists on the surface? |
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Definition
Oxygen/Ozone
Biological life breathes in CO2 and breathes out oxygen. |
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Term
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Definition
| According to einsteins description of gravity, massive objects actually bend space. Light follows dips of space and gets bent off it's original course. We can observe light from a source getting bent Around stars and when there is a planet around the star the light bends around that too |
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Term
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Definition
| Pointing a telescope at a star and looking for a planet. |
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Term
| Why is direct imaging a bad way of looking for a planet? |
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Definition
Therre are a lot of stars out there to search.
Planets are very dim because all we see is the light bouncing off the surface.
We only really see the really large planets |
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Term
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Definition
The building blocks of planets. The disk of material orbiting a young star that will eventually accrete into planets.
This is kind of cheating because you are not actually finding planets, you are finding pre-planets |
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Term
| In the process of looking for Extrasolar planets have we searched the whole universe? |
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Definition
NO
We have just looked in our own galaxy and even then we have only looked at the area right around our own solar system. |
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