What are Tidal Tails?
07-01-2025
07:30 AM
1 min read

Overview:
About 430 million light-years away, in the Leo constellation, astronomers have discovered a nascent ultra-diffuse galaxy forming at the tip of a record-breaking tidal tail extending from the galaxy NGC 3785.
About Tidal Tail:
- Tidal tails are thin, elongated regions of stars and interstellar gas extending into space.
- They are typically formed when galaxies undergo close encounters or mergers, causing their mutual gravitational forces to distort and stretch out material from their outer regions.
- During the interaction, gas and stars are often stripped from the outer regions of the galaxies to form two tidal tails: one trailing and one preceding each galaxy.
- These tails can persist long after the galaxies have finally merged and are therefore considered a signature of recent merger activity.
- Examples of galaxies with tidal tails include the Tadpole Galaxy and the Mice Galaxies.
- Tidal forcescan eject a significant amount of a galaxy's gas into the tail.
- Within those galaxies which have tidal tails, approximately 10% of the galaxy's stellar formation takes place in the tail.
- Overall, roughly 1% of all stellar formation in the known universe occurs within tidal tails.
- Studying tidal tails helps astronomers understand how galaxies interact, merge, and evolve over cosmic time.

Q1: What is a Galaxy?
A galaxy is any of the systems of stars and interstellar matter that make up the universe. Many such assemblages are so enormous that they contain hundreds of billions of stars. Galaxies usually exist in clusters, some of which measure hundreds of millions of light-years across.
Source: DC