dragoni reblogged

What in the Universe is an Exoplanet?

Simply put, an exoplanet is a planet that orbits another star.

All of the planets in our solar system orbit around the Sun. Planets that orbit around other stars outside our solar system are called exoplanets.

Just because a planet orbits a star (like Earth) does not mean that it is automatically stable for life. The planet must be within the habitable zone, which is the area around a star in which water has the potential to be liquid…aka not so close that all the water would evaporate, and not too far away where all the water would freeze.

Exoplanets are very hard to see directly with telescopes. They are hidden by the bright glare of the stars they orbit. So, astronomers use other ways to detect and study these distant planets by looking at the effects these planets have on the stars they orbit.

One way to search for exoplanets is to look for “wobbly” stars. A star that has planets doesn’t orbit perfectly around its center. From far away, this off-center orbit makes the star look like it’s wobbling. Hundreds of planets have been discovered using this method. However, only big planets—like Jupiter, or even larger—can be seen this way. Smaller Earth-like planets are much harder to find because they create only small wobbles that are hard to detect.

How can we find Earth-like planets in other solar systems?

In 2009, we launched a spacecraft called Kepler to look for exoplanets. Kepler looked for planets in a wide range of sizes and orbits. And these planets orbited around stars that varied in size and temperature.

Kepler detected exoplanets using something called the transit method. When a planet passes in front of its star, it’s called a transit. As the planet transits in front of the star, it blocks out a little bit of the star’s light. That means a star will look a little less bright when the planet passes in front of it. Astronomers can observe how the brightness of the star changes during a transit. This can help them figure out the size of the planet.

By studying the time between transits, astronomers can also find out how far away the planet is from its star. This tells us something about the planet’s temperature. If a planet is just the right temperature, it could contain liquid water—an important ingredient for life.

So far, thousands of planets have been discovered by the Kepler mission.

We now know that exoplanets are very common in the universe. And future missions have been planned to discover many more!

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dragoni

We’re NOT Alone!

"exoplanets are very common in the universe“

#exoplanet #exoplanets #earth-like #earth like #earth like planets #nasa #science #planets #space exploration #astronomy #discovery #universe #habitable zone #kepler #kepler space telescope #kepler telescope

dragoni

Caught For The First Time: The Early Flash Of An Exploding Star

The brilliant flash of an exploding star’s shockwave—what astronomers call the “shock breakout”—has been captured for the first time in the optical wavelength or visible light by NASA's planet-hunter, the Kepler space telescope.

An international science team led by Peter Garnavich, an astrophysics professor at the University of Notre Dame in Indiana, analyzed light captured by Kepler every 30 minutes over a three-year period from 500 distant galaxies, searching some 50 trillion stars. They were hunting for signs of massive stellar death explosions known as supernovae.

In 2011, two of these massive stars, called red supergiants, exploded while in Kepler’s view. The first behemoth, KSN 2011a, is nearly 300 times the size of our sun and a mere 700 million light years from Earth. The second, KSN 2011d, is roughly 500 times the size of our sun and around 1.2 billion light years away.

“To put their size into perspective, Earth's orbit about our sun would fit comfortably within these colossal stars,” said Garnavich.

...

"Life exists because of supernovae."

Source: news.ycombinator.com

#nasa #exploding star #kepler space telescope #kepler #ksn 2011a #ksn 2011d #planetary astronomy #astrophysics #science

dragoni

Finding Earth's Twin

Among the methods astronomers have used to discover extra solar planets, the most successful is a technique called transit photometry. It measures changes in a star's brightness caused when a planet crosses in front of its star along our line of sight.

Astronomers using NASA’s Kepler Space Telescope have employed this technique to become the most successful planet-hunting spacecraft to date, with more than a thousand established discoveries and many more awaiting confirmation. Future missions carrying improved technology are now in the works. How much can they tell us about alien planetary systems similar to our own?A great deal, according to a recently published study. It shows that in the best-case scenarios, these upcoming missions could uncover planetary moons, ringed worlds similar to Saturn, and even large collections of asteroids. NASA’s Kepler Space Telescope has used this technique to become the most successful planet-hunting spacecraft to date, with more than a thousand established discoveries and many more awaiting confirmation. Missions carrying improved technology are now planned, but how much more can they tell us about alien planetary systems similar to our own?

#exoplanets #kepler space telescope #nasa #space exploration #science #finding earth's twin #transit photometry #astronomy