I am writing in response to the article in the Jan. 13 issue about the upcoming astrophysics senior review [“Kepler Scientist Pushes Extended Mission for Space Telescope ahead of NASA Review,” page 9].

The article properly describes the K2 mission using the Kepler Space Telescope. However, as the project scientist for the Spitzer Space Telescope, which is in the mix, I have to object strenuously to your characterization of Spitzer as an observatory “now studying aging galaxies.” 

In fact, Spitzer is studying a very wide range of astrophysical problems, which has been the case throughout our 10-plus years as NASA’s Infrared Great Observatory. 

In recent years, the two pillars of our scientific work have been characterizing exoplanets through their thermal emissions, which Spitzer is uniquely capable of doing, and studying recently formed galaxies in the early universe, which we do in tandem with the Hubble Space Telescope. 

More information about Spitzer’s science programs is available at Spitzer.Caltech.edu.

Michael Werner

Pasadena, Calif.