I Can Show You the Worlds: The Science of Planetary Exploration 4/18/2012
Introduction:
Earth is one of the eight planets in our Solar System. Within the past 20 years, astronomers have discovered more than 700 planets in the Universe, which are orbiting stars that are not our Sun. Presently, the Earth remains the only place in the Universe that we know of to harbor life. In this talk, we will discuss the possibility of life beyond Earth, as well as covering what we have learned about our own Solar System and the planets beyond.
Speakers:
Anjali Tripathi is a first year graduate student in Astronomy at Harvard. With Dr. Ruth Murray-Clay, she uses computer simulations to study how an extrasolar planet can lose mass from its atmosphere when it is very close to its host star.
Kirit Karkare is a first year graduate student in Astronomy at Harvard. He works with Professor John Kovac on the design, deployment, and operation of radio telescopes at the South Pole. These telescopes observe the cosmic microwave background, looking for the signature of the physics that drove the birth of the universe.
Sukrit Ranjan is a second-year PhD student in astronomy. Working with Prof. David Charbonneau and Dr. Jean-Michel Desert, he works on using the Hubble Space Telescope to understand the composition of the atmospheres of planets around other stars. In his free time, he enjoys hiking, flying and reading.
Glossary
Biosignature: An indicator for life. Excess methane in the presence of oxygen is considered a biosignature for life on Earth.
Celsius: A temperature scale. 0 C corresponds to the freezing point of water (32 F), 100 C corresponds to the boiling point of water (212 F).
Doppler Effect: A change in the wavelength of light, caused when the source of light is moving.
Extrasolar planet (exoplanet): A planet orbiting a star other than the Sun.
Galaxy: A system of billions of stars held together by gravity. We live in the Milky Way Galaxy.
Hematite: A type of mineral that contains Iron Oxide found on both Earth and Mars. On Earth, it can be formed with the help of water, such as at the bottom of a lake, or with the help of volcanic activity.
Methane: A substance found on Earth, the primary component of natural gas. Sources of methane include volcanoes and biological life. Methane is very flammable. It is unstable in the presence of oxygen.
Orbit: A planet's orbit is the path it takes around its host star. It is usually circular. More generally, an orbit is the path any object takes around a point in space, due to gravity.
Radial Velocity: The speed of an object towards or away from us. We find exoplanets by looking at how the radial velocity of their host stars.
Solar System: The planets orbiting the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. Also includes the moons of these planets, the asteroid belt, and the comets.
Spectrum: The rainbow of colors that is visible when the different wavelengths of light are separated.
Star: An object composed of hydrogen and helium that gives off heat and light due to nuclear fusion. Our Sun is a star.
Transit: When a planet passes in front of a star, causing the total light to dim.
Wavelength: A measure of the “color” of light. Small wavelengths are associated with blue, hot light. Large wavelengths are associated with red, cool light.
Next Seminar (2nd May, 2012): Avian Flu and Scientific Censorship: When Should Scientists Keep their Mouths Shut?
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