U.S. President Joe Biden is making a stealth start by unveiling one of the images next night. The rest will be published on Tuesday evening Finnish time.
The James Webb Space Telescope was sent into space six months ago on December 25th. Since then, the device has been calmly and thoroughly prepared for scientific observations.
At the very beginning, the telescope, which was made into a small package that could fit in the nose of the rocket, was opened. Its tennis-court-sized sunshade was deployed, and the sides of the large mirror were flipped into place. Then the 18 hexagonal parts of the mirror were precisely adjusted to their correct shape.
During the spring, the temperature of the telescope was allowed to drop as low as possible and after that four research instruments were put into use. In all, 17 different operating modes were tested and calibrated.
Everything was ready last week when the first scientific observations began; the images and information to be published now are the results of these observations.
What can be expected from the now published images and how will Webb continue his work from now on? We put together five questions and answers.
1. What objects can we get pictures of?
Over the weekend, NASA published a list of objects that were studied in this first period of observation.
President Joe Biden will announce the first of the pictures on Monday evening. NASA Administrator Bill Nelson hinted last week that the image shows further into the universe than we’ve ever seen before.
It is likely SMACS 0723, a massive galaxy cluster whose members amplify and refract light coming from galaxies much further away in the cluster.
On Tuesday, information on four other objects will be published.
The Keel Nebula, or Carina Nebula, is a large, very diverse gas nebula located approximately 8,500 light-years away from Earth. The nebula can be seen in the southern starry sky in the Köl constellation. The nebula contains the youngest known stars, as well as very large and massive stars. There is also the brightest known star in the Milky Way.
WASP-96 b is an exoplanet in the southern sky in the constellation Phoenix, orbiting the star WASP-96. It is a large planet that is mostly made of gas like Jupiter, but is roughly half the mass of Jupiter. It is about 1,150 light years from Earth and was discovered in 2014.
NGC 3132, or the Southern Ring Nebula, is a planetary nebula about 2000 light-years away in the constellation Purjee. So it is a gas cloud thrown around by a dead star, which is expanding all the time. It is one of the best-studied planetary nebulae, so it is easy to compare Webb’s results with previous observations.
Stephan’s quintet is a dense cluster of five galaxies in the Pegasus constellation about 290 million light-years away from us. Four of the galaxies are located so close to each other that their spiral structure has been broken by the mutual gravity of the galaxies. A fifth of the galaxies in the group happen to be visible only in the same direction.
2. How does Webb take pictures?
While the Hubble Space Telescope is known for the beautiful pictures it takes, the pictures taken by Webb will not be the same. You will certainly get great pictures, but they are taken in the wavelength range of infrared light. Infrared light is difficult to detect from Earth, so Webb was designed to use it.
Webb has four different observation devices, to which the light is directed from a large main mirror. The idea is to break the light into parts and examine the different wavelengths precisely. The photos are taken through different filters, resulting in several images in slightly different infrared wavelength ranges. Combining them provides a lot of information about the object. By processing pictures, you can also get nice “normal” pictures – like, for example, the nice color pictures that are being published now.
All observations are carefully planned in advance, and before and after each picture, calibration pictures are also taken, in which a well-known object is photographed with the telescope for comparison.
3. What is the joy of spectral observations?
Perhaps the most important telescope observations are spectral observations. In them, the light coming from the object is changed into a curve, which tells how much of any wavelength comes from the object. In this way, for example, the molecules in the target can be found and the prevailing conditions there can be deduced.
4. Webb has been hit by micrometeors. Whether they are dangerous?
Yes and no. Webb is quite a large object: its mirror with a diameter of about 6.5 meters has an area of about 25 square meters and the large sun shield of the telescope is almost the size of a tennis court. It is clear that they will be hit by micrometeoroids and will be gradually harmed. This has been taken into account when designing Webb, and its materials have been chosen in such a way that the telescope would withstand collisions as well as possible.
Naturally, it is possible that Webb will also be hit by a large enough piece that it will really hurt. However, this probability is very small.
5. What new information is expected from Webb once it gets up to speed?
After the media frenzy of the release of the first images, the data and observations collected during the commissioning of the telescope will be published on July 13. From this point on, the telescope begins to routinely make observations of objects that have been proposed by astronomers around the world for years; only the best and most interesting proposals are accepted.
Webb will detect many different objects, from the planets and small bodies of our own Solar System to the most distant galaxies in the universe. Webb is something like a hundred times more powerful than the Hubble Space Telescope, so there are likely to be some really interesting observations – maybe even revolutionary ones. Exoplanet observations will be particularly exciting.
What thoughts does the news evoke? You can discuss the topic on 12.7. until 11 p.m.