Do they exist?

For a long time humans thought that Earth was the only planet in the universe with life on it. That was understandable, because without the powerful telescopes we have today, all that could be seen in the sky were some bright stars. How could anything live on stars, places as hot as our own Sun?

However, when powerful telescopes were developed, we were able to see that there were other planets out there in our solar system, and even other solar systems in our galaxy that could be similar to our own. As telescopes became even more powerful, scientists discovered that there were many other galaxies, each containing their own solar systems. Now we realise that our solar system is only one of millions and millions of others in the universe. If there is life in ours, why shouldn't there be life in other solar systems?

Although the discovery of other galaxies and solar systems makes lots of people think that there is other life in the universe, there is still no evidence or proof that this life exists. So we continue to search for alien life by sending radio signals out into the universe, hoping that aliens just might hear and reply to one.