Space Telescope Science
One of the key science goals of NASA’s James Webb Space Telescope is to learn about “first light,” the moment when the first stars and galaxies lit the universe. While the first galaxies will be within Webb’s reach, individual stars shine so faintly that Webb would not be able to detect them without help. That help could come in the form of natural magnification from gravitational lensing, according to a new theoretical paper.
A cluster of galaxies can provide the needed gravitational oomph to bring distant objects into focus via lensing. Typical gravitational lensing can boost a target’s brightness by a factor of 10 to 20. But in special circumstances, the light of a faraway star could be amplified by 10,000 times or more.
If Webb monitors several galaxy clusters a couple of times a year over its lifetime, chances are good that it will detect such a magnified star, or possibly the accretion disk of a black hole from the same era. This would give astronomers a key opportunity to learn about the actual properties of the early universe and compare them to computer models.