Are We Alone In The Universe (4 of 22)

Are We Alone In The Universe

The Keck Telescope high up on Mauna Kea, Hawaii is about as close as you can get to the stars.
It 's the world's largest, because the collecting area of the mirror is the largest in the world.
The mirror is ten metres across, 1/10 the length of a football field, all to collect the starlight coming from hundreds or thousands of light years away.
But even using the mighty Keck telescope, Pluto, at the edge of our solar system, is a colossal 4?billion kilometres away.
And this is the best image astronomers have achieved.
And yet Marcy wanted to look beyond our solar system, to find the hypothetical worlds that astronomers call exoplanets, which lie around other stars.

Like our nearest star, Proxima Centauri, a staggering 40 trillion kilometres away, or four light years.
Beyond lies the rest of our galaxy - an unimaginable 100,000 light years across.
It 's our local neighbourhood of 200 billion stars.
Astronomers knew there had to be planets out there.
We saw young stars with proto-planetary disks of gas and dust around them, surely making planets.
But we couldn't detect the planets.
And the reason is that even with the largest telescope, like this one, the mighty Keck, the planets were lost in the glare of the host stars.
The problem is that compared to the light of a star, the reflected light from an exoplanet is all but invisible.
The star burns a billion times more brightly.