Planet+Quest

T h e S ea r c h f o r A n o t h e r E a r t h


"In 1995, a Swiss team of scientists discovered a planet half the mass of Jupiter orbiting a star 48 light-years from Earth. Today, dozens of other planets have been found outside of our own solar system—some as close as 15 light-years and some as far as 200 light-years away. Some scientists believe that there are thousands of other systems waiting to be discovered. The extrasolar planets we have discovered so far are giants, like Jupiter and Saturn, many orbiting close to their stars. We don’t expect them to support life as we know it. But these same planetary systems might also contain smaller, terrestrial planets. The “holy grail” for planet searchers is a planet closer to the size of Earth, orbiting its star at a constant distance similar to the distance between the Sun and Earth . Why? Because this is the type of planet that is most likely to contain signs of life. If we found water , carbon dioxide , and ozone in the atmosphere , we would be even closer to finding life. But how do we find these smaller planets and determine whether there could be life on them? That is the PlanetQuest mission." (from https://www.nasa.gov/50th/50th_magazine/planetQuest.html ) media type="custom" key="7027993" width="201" height="201" align="right"

Why is Earth so unique?
 * Goldilocks planet **(from https://www.livescience.com/31788-why-earth-perfect-for-life.html condensed and edited by Mrs. Lanier)

"The most impressive attribute of the Earth is the existence and amount of liquid water on its surface," said Geoffrey Marcy, an astronomer at the University of California, Berkeley who has helped discover dozens of extrasolar planets. Water has remained liquid because it is the perfect distance from the sun. If Earth were further out in orbit, the water would freeze. If Earth were closer, the water would boil away. The Earth is in the “just right” location in the Solar System and that is why it is called the Goldilocks Planet.

Earth also has plate tectonics that create islands, mountain ranges and ocean trenches. Plate tectonics also help to keep the Earth warm by adding CO 2 into the atmosphere, contributing to the greenhouse effect. An interesting fact is water helps plate tectonics continue on Earth. “Without water the planet would be geologically dead,” said Caltech’s Mike Brown, who discovered Eris out past Pluto.

Another important characteristic of Earth is its size. If it were smaller, it wouldn’t be able to hold on to the atmosphere and would end up like Mars. If it were larger it might be a gas giant like Jupiter. Jupiter, called Earth’s big brother, has protected Earth by collecting all the rocks that could cause catastrophic damage if they hit the Earth. In addition Earth’s moon helps stabilize Earth's orbit. All this adds up to the very unique planet we call home.

[|Newest 2015 discovery of "Habitable" Earth-Like Planet]
[|Check out this video that talks about search for alien life.]

[|Proof of alien life?] [|Not the first time we have thought this, so don't rush to conclusions.]

[|Check out this video that talks about 5 things that would happen when aliens arrive.]

[|Click here to learn about this search for life on other planets.]

[|Click here to see the top ten planets that might have some form of life.]

[|Click here to learn more about the search for life on other planets.]

M i s s i o n s
http://planetquest.jpl.nasa.gov "Over the next 15 years, NASA is embarking on a bold series of missions to find and characterize new worlds. These will be the most sensitive instruments ever built, capable of reaching beyond the bounds of our own solar system." (from http://planetquest.jpl.nasa.gov/resources/pq_activity_guide.pdf)

[|NASA's Exoplanet Exploration]