How many planets are in our galaxy?

The answer is 50 billion. But I find the number in the Goldilocks zone far more interesting.

At least 500 million of those planets are in the not-too-hot, not-too-cold zone where life could exist. The numbers were extrapolated from the early results of NASA’s planet-hunting Kepler telescope.

Hey look, every Facebook user could have one Goldilocks planet all his or her own.

These numbers could change drastically, but don’t expect to ever see any minuscule estimate by any measure. We have billions of stars in the Milky Way alone; we can predict the number of planets should reasonably be in the billions just by that fact. And if we venture our minds outside our little corner of the Universe, we realize there are more stars than grains of sand on Earth. The total number of planets in the Universe is undoubtedly in the trillions. And I’m probably being conservative. Earth is likely to be mind-blowingly mundane.

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Milky Way kicks out star for eternity

One of the fastest moving stars ever discovered is on its way out of the Milky Way, but Hubble can still see it.

Nasa’s Hubble Space Telescope has detected a rare hypervelocity star that was spat out of the centre of our galaxy and is travelling three times as fast as the Sun.

Scientists believe that it was created when three stars travelling together passed too close to the black hole at the centre of the Milky Way around a hundred million years ago.

One of the stars was captured while the other two were flung out of the galaxy and merged to form a super-hot blue star travelling at around 1.6 million miles per hour.

Creationist interpretation: a deceitful designer placed the star at a high velocity in just such a way that we would be tricked into thinking something plausible had happened instead.

Anyway.

Here are a couple images. The first is a NASA graphic while the second is the actual image.

Hubble Images

SN 1987A

NGC 2440

Small Magellanic Cloud

Beautiful Hubble image

It completely slipped my mind that the winner of the Hubble contest had been released until I saw the absurd number of searches for “Hubble” on my stats page. The winner is ARP 274.

On April 1-2, the Hubble Space Telescope photographed the winning target in the Space Telescope Science Institute’s ‘You Decide’ competition in celebration of the International Year of Astronomy (IYA).

The winner is a group of galaxies called Arp 274. The striking object received 67,021 votes out of the nearly 140,000 votes cast for the six candidate targets.

Arp 274, also known as NGC 5679, is a system of three galaxies that appear to be partially overlapping in the image, although they may be at somewhat different distances. The spiral shapes of two of these galaxies appear mostly intact. The third galaxy (to the far left) is more compact, but shows evidence of star formation.

Two of the three galaxies are forming new stars at a high rate. This is evident in the bright blue knots of star formation that are strung along the arms of the galaxy on the right and along the small galaxy on the left.

The largest component is located in the middle of the three. It appears as a spiral galaxy, which may be barred. The entire system resides at about 400 million light-years away from Earth in the constellation Virgo.

Hubble’s Wide Field Planetary Camera 2 was used to image Arp 274. Blue, visible and infrared filters were combined with a filter that isolates hydrogen emission. The colors in this image reflect the intrinsic color of the different stellar populations that make up the galaxies. Yellowish older stars can be seen in the central bulge of each galaxy. A bright central cluster of stars pinpoint each nucleus. Younger blue stars trace the spiral arms, along with pinkish nebulae that are illuminated by new star formation. Interstellar dust is silhouetted against the starry population. A pair of foreground stars inside our own Milky Way are at far right.

The International Year of Astronomy is the celebration of the 400th anniversary of Galileo’s first observations with a telescope. People around the world came together to participate in the IYA’s 100 Hours of Astronomy, April 2 to 5. This global astronomy event was geared toward encouraging as many people as possible to experience the night sky.

Image Credit: NASA, ESA, and M. Livio and the Hubble Heritage Team (STScI/AURA)

ARP 274