Read More: Mysterious Universe
It’s spring in the Northern Hemisphere, which means anyone with a lawn will soon be spreading fertilizer all over their grass to make it grow long enough and green enough so they can walk on it barefoot for a few days before it turns brown from the drought and excessive heat. According to a new study, that stuff you’re spreading – or at least one element in it — may show aliens in other solar systems evidence that there’s life on Earth. Conversely, the fact that we can’t see it on planets orbiting other stars means they may not have life at all. That element is the ‘P’ in the NPK balance listed on the bag of fertilizer – phosphorus. In a presentation at the European Week of Astronomy and Space Science in Liverpool last week, astronomers Jane Greaves and Phil Cigan of Cardiff University, described what happened when they recently aimed the William Herschel Telescope in the Canary Islands at the Crab Nebula, a supernova remnant located just 6,500 light-years away in the Taurus constellation. The data, which they’ve only begun to process, showed that it contained what would be considered an average amount of phosphorous for the Milky Way – which surprisingly isn’t much. For comparison, Cassiopeia A – a supernova remnant in the constellation Cassiopeia – was found in 2013 to contain 100 times more phosphorous that the Milky Way average. Because it’s such an new and challenging process, these are the only two supernovae analyzed for phosphorus so far. Greaves and Cigan were studying supernova explosions because that is the source of phosphorus in the universe and phosphorus is one of the six chemical elements which all life on Earth depends on. (Can you guess the rest?) In an interview with phys.org, Greaves explains why the low level in the galaxy is a concern to astronomers looking for alien life.