My eighth grade science teacher had a great idea for a weight loss program: just send people to the moon.
Gravitational pull is different on every planet, moon and star. On the moon, we would weigh less. On the sun, we would way 20 times as much as we do on Earth. Now, thanks to research performed by scientists from Germany, Austria, France and Australia, there is a new way to find the gravitation pull at the surface of very distant stars. This information will give critical data about the potential for orbiting planets to harbor life.
Current techniques for approximating gravitational pull only work for stars that are somewhat close to us, but their power diminishes as the star's distance from Earth increases. This new method will apply to stars so far away, the current methods don't apply.
The new technique, called the autocorrelation function timescale technique, measures the brightness of stars and records variance in that brightness over time. That data is collected by satellites and then crunched to determine an approximate gravitational pull.
Once scientists can determine the weight on these stars, they can work backward to figure out the star's mass and radius. The more the star is like our own sun, the more likely it is to have planets that harbor life.
"If you don't know the star, you don't know the planet," said study co-author, Jaymie Matthews, in a press release. "The size of an exoplanet is measured relative to the size of its parent star. If you find a planet around a star that you think is Sun-like but is actually a giant, you may have fooled yourself into thinking you've found a habitable Earth-sized world. Our technique can tell you how big and bright is the star, and if a planet around it is the right size and temperature to have water oceans, and maybe life."
Once scientists have identified stars that would serve as suns for planets like our own, they can look for planets that would be in the "goldilocks zone" of that solar system — the area where it's the perfect temperature for life. The goldilocks metaphor, of course, refers to the children's fable wherein Mama Bear's bed, porridge and clothes are just right for a little girl (creepy? Maybe).
The search for intelligent life in outer space has always been an uphill battle, but there are hints everywhere. In this case, the brightness of a star leads to the gravity of that star, which leads to the radius/mass of that star, which leads to the kind of planets we might find orbiting that star, which leads to the possibility of life. It might sound like quite a riddle — and it is.
The new method is described in a study published this week in Science Advances.
