Context:
Recently, the James Webb Space Telescope has revealed important details about Earendel, the far away celestial body.
Relevance:
GS III: Science and Technology
Dimensions of the Article:
- Earendel
- Gravitational Lensing
- What is NASA’s James Webb Telescope?
Earendel
- Earendel, a star unveiled in 2022 by the Hubble Space Telescope, holds distinction as the earliest and farthest known star.
- Its recognition marks a significant astronomical achievement.
Stellar Attributes:
- Earendel belongs to the massive B-type category, significantly hotter than the Sun and incredibly more luminous.
- Its luminosity surpasses our Sun by about a million times.
Distance and Location:
- Positioned in the Sunrise Arc Galaxy, Earendel resides approximately 12.9 billion light-years away.
- This colossal distance makes it a captivating target of exploration.
Gravitational Lensing’s Role:
- Both Hubble and Webb telescopes identified Earendel through gravitational lensing.
- Gravitational lensing is a natural phenomenon caused by massive celestial objects bending spacetime.
- Earendel’s visibility was magnified due to gravitational lensing caused by galaxy cluster WHL0137-08 situated between the star and our vantage point.
Gravitational Lensing
- Gravitational lensing occurs when a massive cosmic body, such as a galaxy cluster, distorts spacetime curvature enough to visibly bend light around it.
- This phenomenon resembles light passing through a lens.
Gravitational Lens:
- The cosmic body responsible for curving light paths is termed a gravitational lens.
- It acts as a natural magnifying glass, permitting the observation of otherwise distant and faint entities.
What is NASA’s James Webb Telescope?
- The telescope has been in the works for years. NASA led its development with the European Space Agency (ESA) and the Canadian Space Agency.
- It was launched aboard a rocket on December 25, 2021, and is currently at a point in space known as the Sun-Earth L2 Lagrange point, approximately 1.5 million km beyond Earth’s orbit around the Sun.
- Lagrange Point 2 is one of the five points in the orbital plane of the Earth-Sun system.
- Named after Italian-French mathematician Josephy-Louis Lagrange, the points are in any revolving two-body system like Earth and Sun, marking where the gravitational forces of the two large bodies cancel each other out.
- Objects placed at these positions are relatively stable and require minimal external energy or fuel to keep themselves there, and so many instruments are positioned here.
- L2 is a position directly behind Earth in the line joining the Sun and the Earth. It would be shielded from the Sun by the Earth as it goes around the Sun, in sync with the Earth.
What is the mission of the James Webb Space Telescope?
NASA says the James Webb Space Telescope will be “a giant leap forward in our quest to understand the Universe and our origins”, as it will examine every phase of cosmic history: from the Big Bang to the formation of galaxies, stars, and planets to the evolution of our own Solar System.
The science goals for the Webb can be grouped into four themes.
- To look back around 13.5 billion years to see the first stars and galaxies forming out of the darkness of the early universe.
- To compare the faintest, earliest galaxies to today’s grand spirals and understand how galaxies assemble over billions of years.
- To see where stars and planetary systems are being born.
- To observe the atmospheres of extrasolar planets (beyond our solar system), and perhaps find the building blocks of life elsewhere in the universe. The telescope will also study objects within our own Solar System.
-Source: Indian Express
