NASA / ESA / Arizona State University (R. Windhorst and F. Timmes)
Although its release date is uncertain and construction has been delayed, astronomers already have stars in their eyes when they think about the James Webb Space Telescope. It aims to be the replacement of the world-famous Hubble, scientists now hope that with the right conditions can capture the light of individual stars within the first generation of stars in the history of the universe.
Announcement – Continue reading below  It is an intoxicating goal, but scientists insist that it is possible.
"Finding the first stars and black holes has long been a goal of astronomy, they will tell us about the real properties of the early universe, things that we have only modeled on our computers so far," says Rogier Windhorst of Arizona State University, Tempe, an astronomer who talks about Webb's potential in a press release.
The crux of the search for the first stars is the search for stars that have been gravitational. The gravitational lens is an effect of Einstein's theory of general relativity and works according to the principle that the mass bends light. When the gravitational field of a gigantic object extends into space, the nearby rays of light bend and focus again in another place.
Normal gravitational lens can magnify light by factors of 10 to 20, but that is insufficient for what Windhorst and his co-authors wish Webb. On the contrary, they are waiting for something called "caustic cluster transit". In optics, a caustic network refers to how refracted and reflected light is projected onto another surface: think of the light refracted on a table that moves through a glass of water.
If the light of a first star candidate was refracted in a cluster of moving galaxies, the light of the star could be amplified 10,000 times. Given Webb's amazing technical capabilities, that might be enough to capture it.
The possibilities, admits Windhorst, are small. Many things would have to line up exactly, and space is a big place. But it is not impossible in any way. Earlier this year, astronomers used the same gravitational lens principles that Windhorst describes to discover the farthest star, Icarus.
The longer an object shines in the universe, the more likely it is to be part of a gravitational lens. Windorst already has some target clusters to explore Webb, including the monstrous El Gordo cluster.
Announcement – Continue reading below
"We just have to be lucky and observe these groups enough." The astronomical community would have to continue to monitor these groups during Webb's life. Windhorst says.
The Webb will have a full dance card when it finally goes live. Astronomers have no shortage of questions that need answers. The oldest stars would undoubtedly be a huge find: they could teach scientists about the physical properties of the early universe, from the creation of stars to some of the first chemical reactions.
Source: State of Arizona