2011: TWO MAJOR DEVELOPMENTS IN ASTRONOMY AND THE SPACE PROGRAM

SEARCHING FOR EARTH- LIKE PLANETS, AND FOR EXTRATERRESTRIAL LIFE

PART 1: The Search for Other Planets Like Earth (photo – NASA)

Do you recognize this planet?

What is an exoplanet? An exoplanet, or extrasolar planet, is a planet beyond the Solar System, orbiting a star other than our sun.

first exoplanet discovered first exoplanets around regular stars were discovered As of 2/23/11 – 528 (confirmed) exoplanets have been discovered

At first, all of the exoplanets discovered were GAS GIANTS like Jupiter. They could not support life as we know it. This is almost certainly because of the method used to find them.

Many exoplanets were discovered using the RADIAL VELOCITY Method also known as The WOBBLE method

The radial velocity method is based on the gravity of the planet causing the star to “wobble.” The wobble is observed through a Doppler Shift in light

In 2004, the first super-earths were discovered.

The “Transit method” was developed in 1999.

If a planet crosses (or transits) in front of its parent star, then the observed brightness of the star drops by a small amount. The amount by which the star dims depends on its size and on the size of the planet.

The Kepler Space Telescope, successfully launched on March 6, 2009, uses this method.

The Kepler Space Telescope is specifically designed to survey a small region of our galaxy… to find out how common Earth-size planets in the habitable zone are.

The HABITABLE ZONE in astronomy is a region of space where stellar conditions are favorable for life as it is found on Earth. Liquid water can be present!

About one month ago (2/1/11)… Kepler scientists announced the potential discovery of 1,235 more planets. 54 are in the HABITABLE ZONE Of these 54, 5 are NEAR EARTH SIZE!!!

Gliese 581 g is one possibility for an earth-like planet.

artist’s conception of Gliese 581 g

Another way that we can determine if a planet may have life on it is to look at the spectra of the planet – and look for BIOSIGNATURES

In 2007, NASA first directly observed the spectra of two exoplanets. (one of them was HD b)

Water vapor absorption spectrum

HD b First Spectra Seen Of… July 2007 – water March 2008 – methane December 2008 – carbon dioxide Artist’s conception

Recently, researchers at STScI have found that a “possible biosignature could come from life's preference for molecules of a particular handedness…i.e. homochirality, (which) is characteristic of life on Earth” FROM: Astrobiology Magazine, a NASA- sponsored online science magazine What is STScI, and where is it located?

“This handedness or homochirality is a fundamental aspect of self-replication," says Dr. William Sparks of STScI "It is a reasonable proposition that life on other planets will exhibit a particular handedness."

The successor to the Hubble Space telescope will be known as the James Webb Space Telescope It will be launched in 2013 and will allow much more in-depth spectra to be measured

What about “closer to home?” How are they looking for extraterrestrial life right now? (or signs that it once existed.)

Part 2: The Search for Extraterrestrial Life in Our Solar System

January 15, 2009 – Methane gas was observed on Mars. This may be a sign of current life on Mars!!

What is the major thing NASA is looking for on MARS?

“The scientific strategy of NASA's Mars exploration can be summarized as “Follow the Water” The habitability of Mars, past or present, is intimately tied to the presence of liquid water” from Liquid Water on Mars: Is It Still Flowing? By: David Morrison, Senior Scientist NASA Astrobiology institute

June 20, 2008 NASA Spacecraft Confirms Martian Water Phoenix Mars Lander

December 6, 2006 – These images suggest that water could possibly still be flowing on Mars!

Why are they spending all of this time and resources looking for liquid water (or evidence that it is – or once - flowed)?

Life as we know it requires 3 things: 1. nutrients 2. liquid water 3. energy The nutrients appear to be widely distributed…

So the search for extraterrestrial life is often a search for water and energy.

Another question: where else in this solar system is there a possibility of current life??

One possibility: EUROPA – a moon of Jupiter

The surface of Europa is water ice; the core of Europa is hot. In between there is possibly a warm dark ocean - teeming with life!

Europa Jupiter System Mission (EJSM) scheduled to launch 2020 future probe

Artist’s conception of a future Europa mission

Also, there is tiny ENCELADUS- Saturn’s 6 th moon. Until the Cassini spacecraft flew by it in 2005, we had no idea that it was special…

turn/moons/enceladus_geysers_video.html

'Ingredients for Life' Present on Saturn's Moon Enceladus, Say Scientists. Click for article ScienceDaily (Feb. 9, 2010) — University College London scientists.Click for article

IT APPEARS THAT DISCOVERING OTHER “EARTHS,” AND EXTRATERRESTRIAL LIFE IS “RIGHT AROUND THE CORNER!” There are so many things happening in space science – even as we speak! OF IT!! Study your science – and you can be a part of it!

Thanks to NASA for most of the images in this presentation xo/index.html

Water is the Key! But why…. What’s so special about water? STAY TUNED!

Astronomers have found that stars with planets * have a high “metallicity”and * have much less lithium than similar stars without planets

Stars are mostly made of hydrogen and helium. However, stars may have small amounts of other elements such as iron. The percentage of these other elements is called a star’s “metallicity.” Stars with a high “metallicity” are much more likely to have planets than stars with a low “metallicity.”

Another characteristic of planet- bearing stars: they contain far less lithium than stars that do not have planets