What is up with these dwarf galaxies? A survey of thousands of galaxies using the Sloan Digital Sky Survey reveals something interesting, which was first revealed by looking at the massive Andromeda Galaxy nearby Earth: dwarf galaxies orbiting larger ones are often in disc-shaped orbits and not distributed randomly, as astronomers expected.
The finding follows on from research in 2013 that showed that 50% of Andromeda’s dwarf galaxies are in a single plane about a million light-years in diameter, but only 300,000 light-years thick. Now with the larger discovery, scientists suspect that perhaps there is a yet-to-be found process that is controlling gas flow in the cosmos.
“We were surprised to find that a large proportion of pairs of satellite galaxies have oppositely directed velocities if they are situated on opposite sides of their giant galaxy hosts,” stated lead author Neil Ibata of Lycée International in France.
“Everywhere we looked, we saw this strangely coherent coordinated motion of dwarf galaxies,” added Geraint Lewis, a University of Sydney physicist. “From this we can extrapolate that these circular planes of dancing dwarfs are universal, seen in about 50 percent of galaxies. This is a big problem that contradicts our standard cosmological models. It challenges our understanding of how the universe works, including the nature of dark matter.”
The astronomers also speculated this could show something unexpected in the laws of physics, such as motion and gravity, but added it would take far more investigation to figure that out.
The findings were published in the journal Nature.
Source: University of Sydney
Untangling what happened in our Solar System tens or hundreds of millions of years ago…
Back in the 1960s and 1970s, Apollo astronauts set up a collection of lunar seismometers…
The dwarf planet Ceres has some permanently dark craters that hold ice. Astronomers thought the…
Cosmic rays are high-energy particles accelerated to extreme velocities approaching the speed of light. It…
NASA is in the business of launching things into orbit. But what goes up must…
A new theory suggests that Titan's majestic dune fields may have come from outer space.…