Topic 2.4 - Exoplanets Flashcards

1
Q

Who discovered the first exoplanet?

A

Michael Mayor and Didier Queloz of the Observatoire de Genève

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

When was the first exoplanet discovered?

A

1995

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 3 main techniques for detecting or inferring exoplanets?

A
  1. Astrometry
  2. Transit method
  3. Radial velocity method (using Doppler shifts)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is astrometry?

A

Measuring the precise position of the stars relative to each other, if they wobble it’s likely they have an exoplanet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is transit method?

A

Measuring of dips in light of stars to see if a planet has moved in front of it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is Radial velocity method (using Doppler shifts)?

A

The wobbling of a star did to exoplanets gravity can also cause wavelengths to be slightly red-shifted and blue-shifted on a regular time scale as a star moved away from us and towards us Spectroscopy is able to reveal small shifts in wavelength and has been proved the most successful

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What limits the accuracy of astrometry?

A

The turbulence of our atmosphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the problem with the Transit method?

A

It has to be on the same plane as we are in order to see it moving across

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why can’t rocky planets similar to Earth be found using these methods?

A

The atmospheric turbulence and the fact that planets with a relatively small mass have less significant effect on their host star

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the two essential chemical ingredients for life?

A

Carbon and liquid water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why is carbon an essential chemical ingredient for life?

A

It has the ability to make interesting compounds that form the basis of more complex organic molecules, the chemical ‘building blocks’ of life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why is liquid water an essential chemical ingredient for life?

A

It is an excellent solvent and transport mechanism for many nutrients, necessary for photosynthesis and essential for breaking down large molecules into smaller ones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the two principal origins of water?

A
  1. Outgassing of hydrogen and oxygen from volcanoes that combined to produce steam which condensed into water
  2. It was deposited by comets (containing ice) striking Earth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why is it easy to see that earth is the most likely planet in our solar system to sustain life?

A

Mercury and Venus are too hot and Mars and the outer planets are too cold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the habitable zone?

A

A narrow range of distances from the star in which the temperature allows liquid water to exist (sometimes called the Goldilocks zone because it is ‘neither too hot nor too cold’).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Who made the Drake equation and when?

A

Frank Drake in 1961

17
Q

What is the Drake Equation?

A

Combine estimated probabilities of a number of factors That as a result estimate number of civilisations in our galaxy that could communicate with us

18
Q

Name 3 factors of the Drake Equation?

A

N- number of civilisations where communication is possible
R*- average rate of star formation per year in our galaxy
L- length of time signals released into space

19
Q

Name two candidates in our solar system that might possess the correct ingredients for life to exist.

A

Mars and Jupiters moon Europa

20
Q

Name 3 techniques used by astronomers to search for sings of life of other planets.

A
  1. Space probes
  2. Spectral analysis of planetary atmosphere
  3. Analysis of radio waves from space
21
Q

How do we use space probes to search for signs of life?

A

Test for microbes or bi-products

22
Q

How does spectral analysis of planetary atmospheres test for life?

A

Search for gases such as oxygen and methane that are produced by living organisms

23
Q

How does the analysis of radio waves help search for life?

A

Try to detect signals that could have originated from extra terrestrial intelligent forms of life in Galaxy

24
Q

What are the potential dangers of finding life on other planets?

A
  1. Would it be wise to transfer organisms form one environment into a completely different one in which they might become extinct or adapt too well and flourish
  2. We know nothing of the intent or capabilities of the possible alien life-forms so life on Earth could be threatened