304
PEERING BACK
OVER 13.5
BILLION YEARS
STUDYING DISTANT STARS
IN CONTEXT
KEY DEVELOPMENT
James Webb Space
Telescope (2002–)BEFORE
1935 Karl Jansky shows that
radiation other than light can
be used to view the universe.1946 Lyman Spitzer Jr suggests
placing telescopes in space to
avoid atmospheric interference.1998 The Sloan Digital Sky
Survey begins to make a 3D
map of the galaxies.AFTER
2003 The Spitzer Space
Telescope, an infrared
observatory, is launched.2014 The European Extremely
Large Telescope project is
approved, with a primary
mirror 39 m (128 ft) in diameter.2016 LIGO announces the
discovery of gravitational
waves, suggesting a possible
means for looking even farther
than the JWST.T
he James Webb Space
Telescope (JWST) is
designed to be the most
powerful astronomical tool in space,
able to see farther than even the
Hubble Space Telescope. Named
in 2002 after the NASA director
who oversaw the Apollo program,
the JWST is an infrared telescope
equipped with a 21-ft (6.5-m)-wide
gold-plated mirror. This will allow
it to see more than 13.5 billion
light-years into the distance—to
the time when the universe’s first
stars were forming.Conceived in 1995 as the successor
to Hubble, the JWST has had a long
road to completion, encountering
multiple technical hurdles. When
launched in 2018, it will take up
a tight orbit around L2 (Lagrange
point 2), a location 1 million miles
(1.5 million kilometers) beyond
Earth’s orbit, away from the sun.An artist’s impression of the JWST
in space shows the layered stack of
the sunshield unfolded beneath the
telescope. The beryllium mirror is
coated in gold for optimal reflection.