Hubble Finds A Blue Planet Outside Of Our Solar System:
The planet currently known as HD 189733b is one of the closest planets astronomers have discovered outside of our own solar system – only 63 light years away. It was first discovered in 2005, when French astronomers observed it moving in front of its star. And now, astronomers observing the planet with the Hubble Space Telescope have learned something else about it – it’s blue.
Don’t get too excited, though – it’s not blue because it’s covered with water. HD 189733b is bigger than Jupiter and is so close to its star that it’s year is only 2.2 days. Its temperature gets as high as 2,000 degrees. On one side, anyway. Since it’s so close to its star (about 2 million miles away), the planet is tidally locked – meaning only one side of the planet faces the star, period.
In 2007, astronomers made a “thermal map” of HD 189773b and determined that the temperature difference between the light side and dark side of the planet might be as much as 500 degrees. That temperature difference causes enormously fast winds of up to 4500 miles per hour to appear in the planet’s atmosphere. By way of comparison, a category five hurricane has speeds of about 160 miles per hour.
That’s not the only crazy aspect of the weather on this planet. Scientists have also suggested that when it rains on this world, it rains glass.
The clue for that possbility lies in the planet’s blue color. It’s blue not because it’s reflecting water, like our planet, but because the atmosphere contains silicates. Those silicate particles can condense in the cloud to form those glass rains. Those silicate particles also scatter the light in such a way as to make the planet appear blue.