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IndianExpress

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Context

• NASA's James Webb Space Telescope (JWST) has discovered the earliest-known galaxy, JADES-GS-z14-0.
• This galaxy, observed by the JWST Advanced Deep Extragalactic Survey (JADES) program, formed approximately 290 million years after the Big Bang.
• The JADES team also identified another early galaxy, JADES-GS-z14-1, which formed about 303 million years after the Big Bang, with a mass of 100 million solar masses and forming about two new stars per year.

Details

• Size:Measures about 1,700 light-years across.
• Time:Approximately 290 million years post-Big Bang, which translates to the galaxy existing when the universe was just 2% of its current age.
• Mass:Equivalent to 500 million solar masses.
• Star Formation Rate:Rapidly forming new stars, about 20 per year.

Significance of the Discovery

• Earliest-Known Galaxy:Previously, the earliest-known galaxy was dated to about 320 million years post-Big Bang.
• Brightness and Size:The galaxy is surprisingly bright and large, challenging current understanding of galaxy formation in the early universe.

Hypotheses on Brightness 

• Three main hypotheses have been proposed to explain the luminosity of early galaxies:

1. Supermassive Black Holes: Initially thought that supermassive black holes consuming material might cause the brightness. This hypothesis has been ruled out as the light is spread over a wider area than expected from black hole activity.
2. Star Population Density: The galaxies could be more densely populated with stars than previously thought.
3. Star Brightness: The stars in these early galaxies might be intrinsically brighter than stars found in the current universe.

Must read article: James_Web_Telescope

Sources: IndianExpress

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