What is the Herschel Space Observatory?
The Herschel Space Observatory is a space-based telescope that is studying the
Universe by the light of the far-infrared and submillimeter portions of the
spectrum. It is revealing new information about the earliest, most
distant stars and galaxies, as well as those closer to home in space and time.
It has also taken a unique look at our own solar system.
Herschel is the fourth Cornerstone mission in the European Space Agency's
Horizon 2000 program. Ten countries, including the United States, are
participating in its design and implementation. It launched on May 14, 2009,
and is expected to remain an active observatory until early in 2013.
Originally called "FIRST," for "Far InfraRed and Submillimetre Telescope," the
spacecraft was renamed for Britain's Sir William Herschel, who discovered in
1800 that the spectrum extends beyond visible light into the region that we
today call "infrared."
Herschel's namesake has given scientists their most complete look so far at
the large portion of the Universe that radiates in far-infrared and submillimeter
With a primary mirror 3.5 meters in diameter, Herschel is the largest
infrared telescope sent into space as of its launch date. It focuses light
onto three instruments called
which enable Herschel to be the first spacecraft to observe in
the full 60-670 micron range.
More Than Meets the Eye
The far-infrared and submillimeter wavelengths at which Herschel observes
are considerably longer than the familiar rainbow of colors that the human eye
can perceive. Yet, this is a critically important portion of the spectrum to
scientists because it is the frequency range at which a large part of the
The constellation Orion and surrounding space in visible light. Moving
the pointer over the image shows the infrared light image of the same region.
Much of the Universe consists of gas and dust that is far too cold to radiate in
visible light or at shorter wavelengths such as x-rays. However, even at
temperatures well below the most frigid spot on Earth, they do radiate at
far-infrared and submillimeter wavelengths.
Stars and other cosmic objects that are hot enough to shine at optical wavelengths
are often hidden behind vast dust clouds that absorb the visible light and reradiate
it in the far-infrared and submillimeter.
There's a lot to see at these wavelengths, and much of it has been virtually
unexplored. Earthbound telescopes are largely unable to observe this portion
of the spectrum because most of this light is absorbed by moisture in the
atmosphere before it can reach the ground. Previous space-based infrared
telescopes have had neither the sensitivity of Herschel's large mirror, nor
the ability of Herschel's three detectors to do such a comprehensive job of
sensing this important part of the spectrum.
Two-thirds of Herschel's observation time has been made available to the world scientific
community, with the remainder reserved for the spacecraft's science and instrument teams.
The flood of data from Herschel makes it impractical for multiple websites to provide up-to-date or reasonably complete information about all of the observations that have been carried out and published in scientific journals. The following sites are focused on this: