The Hubble Space Telescope still has beautiful remains. While the commissioning of James Webb at the start of the year forced comparisons of all kinds, Hubble proves that it can still take very beautiful shots. 30 years after its commissioning, the telescope still has one of the most powerful mirrors in the world.
A few weeks ago the ESA (the European space agency) decided to turn it to a region of the world that we know quite well. By fixing the galaxy NGC 5495, Hubble did not intend to discover new things, but the device wanted to carry out a completely different mission.
One photo, two eras
The idea was both to succeed in taking a picture of the galaxy, but also to have in the same field of vision of the telescope a star of our Milky Way. The result is quite impressive. If the star seems much brighter than the galaxy in the background, the distances that separate us from these two objects are not at all the same.
Indeed, the star belongs to our own galaxy, the Milky Way, so it is located a few to a few thousand light-years away. Things are very different for the galaxy which is 300 million light-years from us. To give a more telling idea of these figures, if we imagine that the star was on the sidewalk opposite, the galaxy would be 28 kilometers from us (approximately).
Photo of the NGC 5495 galaxy with a Milky Way star in the foreground © ESA/NASA/Hubble
This huge gap also allows us to see two different “epochs” in this same photo. Because of the distance between us and the galaxy, the light has taken years to travel through us, so we see an “old” version of the galaxy. If we can get there in an instant, it wouldn’t look like the Hubble snapshot at all. It’s the same thing for the star but again on very different scales.
Hubble: Grandpa resists
Succeeding in having two elements of the sky in the same image is therefore a feat. But in addition to this incredible framing, the ESA has achieved another feat. The challenge was indeed to succeed in “containing” the arrival of light within the telescope. If the device had been exposed to the light of the star for too long then it would have taken over the galaxy which would have disappeared.
With this perfect balance, ESA has achieved a great feat. If the scientific world will surely not learn much from this shot, it is a superb demonstration of ESA’s work capacities. Very good news for the years to come, where the agency will be able to use a much more powerful device: the James Webb.
In recent weeks Hubble has been put to use many times. It was notably used by NASA to observe the asteroid Dimorphos a few hours after the impact caused by the DART mission. After its use by ESA, it returned earlier this month to NASA, which used its primary mirror to observe very distant areas of the sky.
Hubble and James Webb: the winning duo of space observation
For the first time in its history, the American space agency has two telescopes of such power in space. It intends to take advantage of this window of opportunity to carry out additional observations on interesting areas of our sky such as star nurseries.
These birth zones are a crucial place to understand the origins of our own Sun. Only very powerful telescopes can pierce the mysteries of these remote corners of the Universe. The joint use of Hubble and James Webb could thus enable science to make a great leap forward.
