A visualization of the Radcliffe wave, a series of clouds of dust and gas (marked here in red) through the Milky Way. It is around 400 light years from our sun, marked in yellow
Alyssa A. Goodman / Harvard University
Our solar system has crossed a vast wave of gas and dust approximately 14 million years ago, the view of the earth on the night sky. The wave may even have left traces in the geological file of our planet.
Astronomers have already discovered Large stars used waves, gas and dust in the Milky way that waves from top to bottom over millions of years. One of the closest and most studied of these is the Radcliffe wave, which is almost 9,000 light years old and is only around 400 light years from our solar system.
NOW, Efrem Maconi At the University of Vienna and his colleagues discovered that the Radcliffe wave was once closer to us, crossing our solar system between 11 million and 18 million years.
Maconi and his team used data from the Gaia space telescope, which followed billions of stars in the Milky Way, to identify groups of stars recently formed in the Radcliffe wave, as well as the clouds of dust and gas from which they were formed.
Using these stars to indicate how the wave as a whole moves, they followed the orbits of the clouds in time to reveal their historical location. They also calculated the past path of the solar system, wrapping the chronometer of 30 million years, and found that the wave and our sun have made a close approach between 15 million and 12 million years. Estimated exactly when the level pass has started and ended is difficult, but the team thinks that the solar system was in the wave about 14 million years ago.
This would have made the galactic environment of the earth darker than it seems today, because we are currently living in a empty region space. “If we are in a denser region of the interstellar medium, it would mean that the light from the stars to you would be attenuated,” explains Maconi. “It's like being in a misty day.”
The meeting may also have left evidence in the geological file of the earth, depositing radioactive isotopes in the crust, although it is difficult to measure since there is time, he says. Explain the geological file of the earth is a continuous problem, so finding galactic meetings like these is useful, said Ralph Schoenrich at College University in London.
More specifically, the crossing seems to have occurred during a period when the earth was cooled called Middle Miocene. It is possible that the two are linked, explains Maconi, although it is difficult to prove. Schoenrich thinks it is unlikely. “A general rule is that geology prevails over any cosmic influence,” he says. “If you move the continents or interrupt ocean currents, you get climate changes, so I'm very skeptical that you need something more.”
