195
journey just 1.5 billion years
after the Big Bang. In 2004, the
Ultra Deep Field showed objects
13 billion light-years away, and
in 2010, HST used infrared
radiation to make the eXtreme
Deep Field of objects that existed
just 480 million years into the
history of the universe. To see
farther than this will require
the infrared James Webb Space
Telescope in 2018.
Spitzer in space
HST is the most famous of the four
great observatories that are Lyman
Spitzer Jr.’s legacy. Between 1991
and 2000, the Compton Gamma
Ray Observatory looked at gamma-
ray bursts, energetic events that
ATOMS, STARS, AND GALAXIES
occur at the edge of the visible
universe. The Chandra X-ray
Observatory was launched in
1999, and is tasked with finding
black holes, infant solar systems,
and supernovae. The final member
is the Spitzer Space Telescope,
which entered space in 2003.
One of its tasks was to peerThe Spitzer Telescope was named
by NASA to honor the vision and
contributions of Lyman Spitzer Jr.
It was initially called the Space
Infrared Telescope Facility.into nebulae to pick out the hot
zones where stars are forming.
In 2009, the liquid helium that
kept its heat-sensitive detectors
cool finally ran out.
Observatories can be placed
in orbit around the sun rather than
Earth, where it is easier to shield
them from the sun’s heat and light
and they have a wide, unobstructed
view of the sky. Today, there are
about 30 observatories in orbit,
sending back images. NASA’s
Kepler, which searches for
extrasolar planets, and two ESA
missions, Herschel and Planck,
are examples. All were launched
in 2009. Herschel was the largest
infrared telescope ever put into
space, while Planck studied the
cosmic microwave background.
In 2015, ESA launched the LISA
Pathfinder to test the technology
for a space observatory that would
detect not electromagnetic waves,
but gravity waves. Not even Lyman
Spitzer Jr. could have predicted
such an advance. ■Taken in 2004, the Ultra Deep
Field reveals thousands of jewel-like
galaxies in a variety of shapes,
colors, and ages. The red galaxies
are the most distant.