Study: the Universe Has Almost Stopped Making New Stars

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."

Re:And...

[spire3661]

Tobacco is overrated, Colorado and Washington are where its at.

Re:Fermis paradox

[oodaloop]

Um, we know pretty well how stars are formed. Hydrogen gas is slowly drawn together from gravity, accelerates as it gets closer, and eventually sets itself on fire. with less and less hydrogen gas freely floating around, it makes sense fewer stars would be forming.

Nonsensicle statistics

[Charliemopps]

95 percent of all the stars that this universe will ever see have already been born

And since, based on all the studies we've done, the universe is flat... and therefor infinite... 5% * infinity is what? Infinity. So perhaps star formation will be less dense going forward, but I believe back when it was a lot more active, the universe was probably a lot less hospitable to those of us that don't find gamma ray bursts good for our health.

We now know that the universe is flat with only a 0.5% margin of error. This suggests that the Universe is infinite in extent; however, since the Universe has a finite age, we can only observe a finite volume of the Universe.

Source: http://map.gsfc.nasa.gov/universe/uni_shape.html [nasa.gov]

along those lines: Fade to Black...

[Fubari]

Fade to Black: The Night Sky of the Future [scientificamerican.com] is a slide show that considers the long term implications of cosmic expansion. Here's an excerpt from the introduction page.

The night sky on Earth (assuming it survives) will change dramatically as our Milky Way galaxy merges with its neighbors and distant galaxies recede beyond view.
The quickening expansion will eventually pull galaxies apart faster than light, causing them to drop out of view. This process eliminates reference points for measuring expansion and dilutes the distinctive products of the big bang to nothingness. In short, it erases all the signs that a big bang ever occurred.
To our distant descendants, the universe will look like a small puddle of stars in an endless, changeless void.

Re:Fermi's Fallacy

[Graymalkin]

There's also the fact that if we took the largest, most powerful radio telescope we have, put it on a planet orbiting our nearest star, pointed it directly at earth with the most powerful broadcast it could generate... by the time the signal got to us, there is no equipment on earth that could detect it.

That's completely false. If you took Arecibo and stuck it in orbit around Alpha Centauri and beamed a signal back it would be fairly easy to detect with an Arecibo-class telescope provided we were looking. For a little more on the math read up [computing.edu.au]. We could receive transmissions from dozens of light years away with existing telescopes and even further away with arrays and/or locations with better signal-to-noise ratios than available on planet (like the dark side of the Moon).

Re:Fermis paradox

[Alamais]

Er, no. Yes, it accumulates due to gravity, but it does not "set itself on fire due to acceleration": hydrogen fire (i.e. combustion) is a chemical reaction with oxygen (2 H2 + O2 -> 2 H2O). A 'star' is an accumulation of hydrogen until the pressure and heat due to self-gravitation are sufficient to allow sustained nuclear fusion to occur.