Large galaxies absorb smaller ones in order to survive in the universe, according to a new study recently published in the Monthly Notices of the Royal Astronomical Society.
“All galaxies start off small and grow by collecting gas and quite efficiently turning it into stars,” Dr. Aaron Robotham, lead researcher, said according to the International Centre for Radio Astronomy Research.
“Then every now and then they get completely cannibalized by some much larger galaxy,” he said.
Astronomers looked at the behaviors of more than 22,000 galaxies from data collected by the Anglo-Australian Telescope in New South Wales as part of the Galaxy And Mass Assembly (GAMA) survey.
Larger galaxies have difficulty creating stars. One theory why, according to Robotham, is that the nucleus heats up the galaxy’s gas so much that it is unable to cool down to create stars. Although star production slows, gravity increases for larger galaxies, making it easier for them to pull in smaller, neighboring galaxies.
Our own galaxy, the Milky Way, is set for collision with neighboring Andromeda in 5 billion years. Our largest neighbor at 2.5 million light-years away, Andromeda, is expected to swallow us up after collision.
Data on colliding galaxies, as well as information on the developmental stages of galaxies, have been captured by The Hubble Space Telescope, which launched in 1990.
In October 2018, the James Webb Space Telescope, Hubble’s tennis-court sized successor, will launch.
With longer wavelengths, Webb will not only be able to look further back in time at the early universe’s first galaxies, but it will be able to peek inside dust clouds and send information about planetary systems being formed today.