Thanks to Hubble’s optics, we can see distant objects that otherwise wouldn’t be visible.
Astronomers pointed the HST to a seemingly-empty patch of sky,
and were surprised with what they saw. The “empty” patch of sky
contained over 3,000 galaxies too distant to be viewed by other
telescopes. Subsequent deep field observations have yielded even
more information, and never-before seen views.
In addition to gazing at the early universe, Hubble has helped astronomers determine the age of the universe. By measuring a special kind of pulsing star known as a Cepheid variable, astronomers
were able to narrow down the age of the universe from the pre-HST
range of 10 to 20 billion years, to the more precise 13.7 billion year
age.
The Hubble Space Telescope is also capable of examining individual stars across various stages of their evolution – from the clouds
of dust that form the embryonic stellar cocoons to the corpses of
stars that went supernova, and every stage in between.
At Hubble’s control center at the Space Telescope Science Institute in Baltimore, Md., Larry Stake
monitors Hubble operations. All the commands transmitted to Hubble, including the instructions on
recording scientific data and orders on which stars to observe, come from here. Hubble is monitored constantly by four teams, each made up of a quartet of flight controllers. Credit: STScI
Stars in other galaxies are fairly easy to see, but the planets orbiting them present a challenge. The idea of extra-solar planets, or
exoplanets, used to be a thing of science fiction; however, in 2008,
Hubble captured pictures of the planet Fomalhaut b --the first exoplanet directly imaged in visible light. Most planets are challenging
to photograph, and most of Hubble’s exoplanet discoveries were
not directly imaged. The transiting method of exoplanet detection
is made by the detection of a dip in the host star’s brightness as the
planet passes in front.
Hubble may spend much of its time peering light-years from
Earth, but occasionally will be used to photograph the planets in
our own solar system. High resolution images taken of Jupiter, Saturn, and even Pluto can provide insights that can only be topped
by planetary probes in orbit around them. Images from Hubble
allow scientists on Earth to monitor changes in the planet’s atmosphere and surface. When the comet Shoemaker-Levy crashed
into the Jupiter in 1994, Hubble photographed the fatal collision.
Recently, Hubble detected a possible sub-surface ocean in the Jovian moon Ganymede.
Despite its turbulent beginning, the Hubble Space Telescope has
been operating for a quarter of a century, providing scientists with
a greater understanding of the universe as a whole. Hard to fathom
that children today have lived in a world that’s always contained
the Hubble Space Telescope.