The Universe reveals itself in a multitude of colours.
Even though Hubble can see a large part
of the electromagnetic spectrum
from the ultraviolet to the near-infrared
it still cannot see the whole cosmic kaleidoscope.
So astronomers need different kinds of telescopes,
both in space and on the ground,
to fully unveil the mysteries of the Universe . . .
. . . and Hubble plays a key role
in this essential telescope teamwork.
The Universe looks very different
in the light of different wavelengths,
and many scientific questions can only be answered
by studying objects in specific parts of the spectrum.
Modern telescopes are often built to study
a very specific wavelength range
a small part of the electromagnetic spectrum
in which they are the experts.
With the current state of technology,
no telescope, not even Hubble,
can see all wavelengths.
Only by using data obtained with different telescopes
can astronomers study the Universe in maximum detail.
The history of galaxy formation
and the chemical structure of galaxies
are just two of the many astronomical puzzles
that scientists would like to solve.
Progress towards answers is only possible
by mapping the emission
coming from all the different players:
stars, dust and gas.
Each one leaves its signature in different wavelengths.
For instance, the same portion of space
studied by Hubble can be observed
by the instrumentation aboard
the Chandra X-ray space observatory.
Hubble and Chandra have teamed up
many times in the past.
An example is this image
of the spiral galaxy ESO 137-001.
Thanks to Hubble’s contribution,
the stars and nebulae in the galaxy are made visible.
Chandra, on the other hand,
can show up the hot gas streams,
as they are only visible in the X-ray part of the spectrum.
But Hubble is not only working together with other space telescopes;
it also cooperates with ground-based ones —
and while telescopes in orbit have the advantage
of being immune to atmospheric turbulence,
instrumentation on the ground can be continuously updated
and often show a bigger field of view.
A good example is ESO’s Very Large Telescope
on Cerro Paranal, in the Chilean Atacama desert.
The galaxy cluster Abell 2744
— nicknamed Pandora’s Cluster —
was observed with these two very different eyes.
The combined data showed that Pandora’s Cluster
is in fact not one cluster, but the result of a pile-up
of at least four separate galaxy clusters.
Many requests for telescope time are to follow up
studies of targets investigated previously:
in 2015 astronomers combined older Hubble data
with new observations from ESO’s Very Large Telescope.
The latter had just been used to discover
some previously unknown structures within the dusty disc
surrounding the nearby young star AU Microscopii.
Only on comparison with earlier Hubble images
of the same object, was it discovered
that the features on the disc had changed over time.
It turned out that those ripples are actually moving
— and very fast —
a sign of something truly unusual going on,
and still today an unsolved mystery.
In the last twenty years the hunt for exoplanets
has become a crucial and very prolific
field of study in astronomy;
a field in which almost all telescopes try to make their mark.
For this hunt Hubble teamed up
with the Spitzer infrared space telescope.
Together they produced the largest comparative study
ever of ten hot Jupiter-sized exoplanets.
The multiple observations of their atmospheres
allowed astronomers to extract the signatures
of various elements and molecules
— including water —
and to distinguish between cloudy
and cloud-free exoplanets.
Sometimes, more than two telescopes have to
work together to achieve a common goal.
To witness the earliest stages of a massive galaxy
forming in the young Universe, astronomers used
the power of four large telescopes:
Hubble,
Spitzer,
ESA's Herschel Space Observatory
and the Keck Observatory in Hawaii.
Together the four telescopes observed the early growth
of a galactic giant as it appeared eleven billion years ago,
just three billion years after the Big Bang.
The next big partner of Hubble will be the forthcoming
NASA/ESA/CSA James Webb Space Telescope.
It is scheduled for launch in 2018.
While Hubble can see ultraviolet, visible,
and some infrared light,
James Webb is specialised for the infrared.
With this capability it will be
the perfect complement to Hubble.
Together they will write another chapter
in the story of successful telescope teamwork.