Transcript Earth - Physics @ IUPUI

Goal: To understand what it
will take to find another “Earth”
Objectives:
1) To learn about What type of stars and planets
to look for if we want to find life
2) To understand How to find these planets
Problems:
• Current methods do not look at planet
directly.
• No way of telling if there is life on the
planet.
Finding smaller planets
• Eventually we want to find Earth sized
planets.
• We are getting to smaller and smaller and
will continue to do so.
• However, to do better we need to go to
space!
Interferometer
• An interferometer is a telescope that is slit into two or
more parts and spread out over a large area.
• What this does is effectively gives you a bigger diameter
to your telescope.
• Since resolution ONLY depends on effective diameter,
and not the amount of light your collect, this can give you
very good resolution.
Why not done already in optical
• One complication, you have to be able to
know the distance between telescopes
accurate to the wavelength of light.
• For radio this is easy because the
wavelengths are long.
• For infrared and optical this is hard
because the wavelengths are very tiny.
What it will do
• Allow you to get a better separation of star and
planet on the image
• Allow you to watch the two objects orbit each
other
Advantages
• Can be used on any star.
• Can be used to detect planets as small as
the earth!
• Can be used to find planets further away.
• HOWEVER: The star is still much brighter
than the planet
We want to find LIFE!
• To do this we have to look at a planet.
• However, planets are so small that we
have no hope of actually imaging their
surface features from many light years
away – sorry no finding oceans and
continents.
• So what can we do?
Chronographs
• When you have multiple detectors for
measuring light you can determine how
you add those together.
• If you are clever you can get them to add
together.
• If you are even more clever you can get
them to cancel out!
Blocking the star
• To image a planet directly you have to get
rid of all the light from the star.
• If you can do that then you have a better
shot at imagine a planet.
• If you can image the planet you can take
its spectrum.
Finding life
• How do we determine if there is life?
• We need a signature that only life would
be able to create.
• Stay tuned….
Conclusion
• We need an interferometer to be able to
separate the planet and star on the image
• We need a Chronograph to block the light from
the star to see the planet directly
• We need to take a spectrum of the planet