Pune researchers have uncovered a remarkable discovery: a massive, grand-design spiral galaxy that existed in the universe's infancy. This galaxy, named Alaknanda after a Himalayan river, challenges existing theories on galactic formation. Alaknanda, found by researchers Rashi Jain and Yogesh Wadadekar using NASA's James Webb Space Telescope, is one of the most distant spiral galaxies ever observed, dating back to just 1.5 billion years after the Big Bang. This discovery suggests that the early universe was more evolved than previously thought, with sophisticated structures forming much earlier than expected.
Alaknanda's similarity to the Milky Way is striking, despite being present when the universe was only 10% of its current age. The galaxy contains approximately 10 billion times the mass of the sun in stars and is forming new stars at a rate of about 63 solar masses per year, which is nearly 20 to 30 times the Milky Way's current rate. This finding contradicts the belief that early galaxies were chaotic and clumpy, with stable spiral structures emerging only after several billion years.
Dominant models suggested that early galaxies were too 'hot' and turbulent to form ordered disks capable of sustaining spiral arms. However, Alaknanda's rapid assembly of 10 billion solar masses of stars and the construction of a large disk with spiral arms in just a few hundred million years challenge these theories. The discovery adds to the growing evidence from the James Webb Space Telescope that the early universe was more evolved than previously assumed.
The researchers chose the name Alaknanda due to its connection to the Milky Way, as it is one of the two main headstreams of the river Ganga. Follow-up observations are planned to measure the galaxy's disk rotation, which will help scientists understand how its spiral arms formed. This discovery invites further exploration and discussion, as it challenges our understanding of the early universe and galactic evolution.
