The Spitzer Space Telescope was launched on August 25, 2003, from Cape Canaveral, Florida.  
Designed to last up to five years, on its fifth anniversary it's still going strong, 
and still surprising scientists.
Probably the biggest surprise of the mission came in 2005, 
when Spitzer became the first telescope to directly detect light from a planet around another star.
Scientists thought this was impossible for Spitzer to do.
But then they realized that if a planet is behind its star, the light Spitzer picks up is the light from only the star, 
but the rest of the time, the light Spitzer sees is the light of the star plus the planet.  
Well, all the scientists had to do was subtract the light of the star out, and they were left with only the light of the planet! 
But did you know that Spitzer also helped kill Pluto? 
When Sedna and Eris were were first discovered, their discoverer used Spitzer to help determine how big they are.  
The fact that Eris is bigger than Pluto helped convince the astronomical community to create a new class of objects -- dwarf planets -- for Pluto and its siblings.
But it's not just our solar system that the Spitzer Space Telescope is learning more about.
Spitzer has shown that planets can form in surprising places 
Including around tiny Jupiter-sized objects called brown dwarfs.
And around binary stars.
And even around a star that blew up in a giant supernova 100,000 years ago!
And recently, Spitzer discovered that our own Milky Way galaxy has been drawn wrong for years, 
and removed two spiral arms from the picture!
So as the Spitzer Space Telescope continues to surprise us with new results, 
stay tuned for more "Ask an Astronomer" questions, coming soon!
