The American space agency, NASA, is preparing to launch the James Webb Space Telescope (JWST) in 2021. This technologically advanced tool will employ a naturally occurring phenomenon known as “gravitational lensing” to perform astronomical observations.
The JWST’s Mission and TEMPLATES
The main objective of the JWST is to investigate every phase of our Universe’s history. These phases include the initial bright light that followed the Big Bang, the evolution of solar systems able to support life on planets similar to Earth, and the development of our own Solar System, among others. To accomplish this goal, NASA has initiated a program named Targeting Extremely Magnified Panchromatic Lensed Arcs and Their Extended Star Formation, or TEMPLATES for short.
Understanding Gravitational Lensing
Gravitational lensing is a phenomenon that takes place when a large amount of matter like a massive galaxy, a cluster of galaxies, or a black hole forms a gravitational field. This field then distorts and amplifies the light coming from objects lying behind it.
The concept of gravitational lensing is based on Einstein’s theory of general relativity which proposes that mass bends light. Regular lenses, such as those in a magnifying glass, work by refracting, or bending, the light rays that pass through them to focus the light elsewhere. In a similar fashion, the gravitational field of a bulky object causes the light rays passing near that object to bend and refocus at another place. The more massive the object, the stronger its gravitational field will be, resulting in a greater bending of light rays.
Gravitational Lenses as Cosmic Telescopes
Gravitational lenses operate like natural cosmic telescopes. They enable researchers to examine the details of early galaxies that are too distant to be seen otherwise, even with the most powerful space telescopes.
Pitfalls and Potential: Gravitational Lensing
| Pros | Cons |
|---|---|
| Allows study of faraway galaxies | Rare occurrence |
| Aids understanding of black holes, dark matter | Requires precise alignment of observer and celestial body |
Despite its potential, gravitational lensing is quite rare. This is due to the requirement for a distant star, black hole, and the observer on Earth to be precisely aligned. However, when this phenomenon does occur, it can aid astronomers in gaining valuable insights about black holes, dark matter, and other cosmic entities.
