Study: the Universe Has Almost Stopped Making New Stars 228
A reader sends this quote from Wired:
"An international team of astronomers used three telescopes — the UK Infrared Telescope and the Subaru Telescope, both in Hawaii, and Chile's Very Large Telescope — to study trends in star formation, from the earliest days of the universe. Extrapolating their findings has revealed that half of all the stars that have ever existed were created between 9 and 11 billion years ago, with the other half created in the years since. That means the rate at which new stars are born has dropped off massively, to the extent that (if this trend continues) 95 percent of all the stars that this universe will ever see have already been born. Several studies have looked at specific time 'epochs', but the different methods used by each study has restricted the ability to compare their findings and discern a fuller model of how stars have evolved over the course of the entire universe's lifespan."
Fermis paradox (Score:4, Interesting)
I found that interesting (Score:2, Interesting)
I've often casually thought about star formation when viewing images of planetary nebula like the Orion nebula. The captions/descriptions almost always mention that the nebula was the remnants of a star, and then point out areas of new star formation. But the math never really added up, since one nebula would have a bunch of stars and no explanation is usually given.
I guess that's just a round about way of saying that I subconsciously expected the findings here to be true. It's nice that someone went to the effort to schedule the telescope time and document this.
Reminds me of The Last Question (Score:3, Interesting)
http://en.wikipedia.org/wiki/The_Last_Question
Re:along those lines: Fade to Black... (Score:2, Interesting)
According to current theory, the universe inflated rapidly, then slowed to a gradual expansion, then began accelerating again. The dynamics behind this are completely unknown. And yet you do a naive linear extrapolation to forecast what will happen for periods up to 7000x greater than the current age of the universe.
Re:Fermi's Fallacy (Score:2, Interesting)
Check your own source... it would be possible to detect high powered and precisely targeted communication from Alpha Centauri with an Arecibo size receiver (the biggest we ever made for this type of radiation, mind you), if the receiver itself is pointing at the source.
Now imagine there was a planet the size of earth at Alpha Centauri, and you cut it in half and turned _the entire planet half_ into a telescope. Aimed directly at earth, according to the source you linked, you would detect _absolutely no signals_, since afaik we have not been blasting the Centauri system with highly directed transmissions four years ago.
Keep in mind that the average distance we're dealing with is in the thousands of light years, and that flux density decays quadratically.
You're right that GP has made up a false fact, but no need to overdo it in the opposite direction. To get the slightest signal, we need:
- an emitter willing to target earth, among a few hundred billion stars to chose from (lets keep to our own galaxy)
- to listen somewhat exactly in this emitters direction, with the right type of receiver, which again is one of a lot possible combinations
- this to happen at the same time, out of billions of years to chose from
So yeah, SETI might not be the most promising program. But it's cool and there's highly useful tech from developing all the stuff to get it running.