The Hubble Telescope spotted a string of “galactic pearls”

Tails of colliding galaxies

The Hubble Space Telescope is precise enough to detect clusters of newborn stars along these tidal tails. They form when galactic gas structures collapse due to gravity, giving rise to about a million new stars per cluster, or star cluster.

The telescope recently examined in more detail 12 interacting galaxies, whose long, tadpole-like tidal tails are composed of gas, dust and lots of stars. Hubble's exceptional sensitivity and resolution in ultraviolet light allowed it to detect 425 clusters of newborn stars distributed along the tidal tails. They look like strings of shiny pearls or Christmas lights. Each cluster contains an estimated one million blue newborn stars.

Star clusters found in the tidal tails of galaxies have been known for decades. When galaxies interact with each other, that is, begin to attract each other, it is gravitational tidal forces that pull long filaments of gas and dust from them. The two most common examples of such galaxy pairs are antennae (also known as antennae) and mouse galaxies – with long, narrow, finger-like protrusions.