Supernova Left Its Mark In Ancient Bacteria 37
ananyo writes "Sediment in a deep-sea core may hold radioactive iron spewed by a distant supernova 2.2 million years ago and preserved in the fossilized remains of iron-loving bacteria. If confirmed, the iron traces would be the first biological signature of a specific exploding star. Scientists have found the isotope iron-60, which does not form on Earth, in a sediment core from the eastern equatorial Pacific Ocean, dating to between about 1.7 million and 3.3 million years ago. The iron-60, which appears in layers dated to around 2.2 million years ago, could be the remains of magnetite chains formed by bacteria on the sea floor as radioactive supernova debris showered on them from the atmosphere, after crossing inter-stellar space at nearly the speed of light."
Bacteria (Score:1)
Rust (Score:3)
At places where iron rusts (oxidizes) you will find the so-called "iron loving" bacteria
But be careful, some of them can cause Tetanus
http://en.wikipedia.org/wiki/Tetanus [wikipedia.org]
Maybe it woul be... (Score:1)
an interesting evidence about some "recent" mass extintion event:
http://en.wikipedia.org/wiki/Mass_extinction#Lesser_extinctions [wikipedia.org]
Re: (Score:1)
I'm not saying it's aliens, but... (Score:3, Funny)
One supernova of many in Local Bubble (Score:5, Informative)
Our solar system resides in an area of our galaxy called the "Local Bubble" [wikipedia.org], roughly a few hundred lightyears across. This region is very empty compared to the average interstellar medium in the galaxy, as a result of a large number of supernovae that blew out a sort of cavity in our interstellar neck of the woods long ago. In actual structure it's more of an irregular "Local Chimney" [solstation.com] going right through the galactic disc rather than a spherical bubble.
As a result, pinning the cause of TFA's observations to a single supernova is not all that simple, as supernovae were very common in the Sun's general neighborhood in our galactic past..
Here's a nice graphic of the larger features in and around our local bubble [nasa.gov]. It's a fascinating subject if you enjoy understanding our location in a galactic context.
Re: (Score:1)
That's interesting, but they haven't really linked this to a specific nova, but to a group of stars [wikipedia.org] a set of which have gone nova in the "recent" past. (And that link was done a decade ago... this is linking the same through biological interaction.)
Re: (Score:1)
Indeed.
Scorpius-Centaurus is one of the nearest stellar associations in the local bubble, and contains many possible candidates. The Wikipedia article on the Scorpius-Centaurus Association [wikipedia.org] actually alludes to the Fe-60 research as well.
Re:One supernova of many in Local Bubble (Score:5, Interesting)
It's one of the few (to me) persuasive arguments that life might be quite rare, in that so many other ways our sun and system is apparently entirely pedestrian.
Our seemingly interesting local neighborhood and circumstances for only the last 5-10 million years might mean that intelligent life - on this planet at least - might be existing only in what (on a galactic scale) amounts to a spark floating for a moment in the flickering gap between tongues of a campfire's flame.
It's humbling, really.
Re: (Score:2, Informative)
It's one of the few (to me) persuasive arguments that life might be quite rare
Rare? What are you talking about? The Earth gets blasted by supernovas, and all we get is some minor deposits in a geological layer. Not even a major extinction. Nothing.
I would say it shows that life is much more resilient than people think. And the Local Bubble just shows how common it must be.
If anything, I would not be surprised if there is active and viable life forms living underground on Mars. Atmosphere blown away? No problem! Just live underground. All life needs is some catalysts, chemicals and a
Re:One supernova of many in Local Bubble (Score:4, Interesting)
> life might be quite rare ... ... ...
and
> life is much more resilient
I'm going to split the difference between you two. I just finished reading John Gribbin's "Alone In The Universe: Why Our Planet Is Unique." Yes, it's another rehash of the "Rare Earth" hypothesis, but he bases it on some of the latest computer simulations.
Gribbin says that *simple single-celled life* might be very common throughout our Galaxy. But Gribbin makes the argument that *sentient* life is probably quite rare.
You may not agree with his conclusion, but he presents the latest evidence and theories for solar system formation. Well worth the read.
Re: (Score:2, Interesting)
From his metaphor of the spark and the campfire flames, I suspect that the parent meant that for the last several tens of thousands of years of our solar system's voyage through space, we've enjoyed the relative peace and quiet of the Local Bubble's emptiness.
Prior to that, it wasn't always this quiet. The rate of accreted objects from the denser molecular clouds through which we travelled hitting us, as well as the perturbation of the Sun's distant outliers sending them inwards at a higher rate than now,
Re: (Score:2, Interesting)
Before you get humbled much further, consider that life has existed on this planet for billions of years. By comparison, Wikipedia places the age of the bubble at ten to twenty million years. In other words, dinosaurs went extinct more than three times as long ago as the bubble has been in existence. Primates had already evolved by the time the bubble came into existence, and early protohumans were using stone tools by the time the Earth was being showered by the radioactive iron the article talks about.
Re: (Score:2)
There are typically more than 1 planet per star. But let's say there is only 1 planet per star for this case.
Even 1 in a billion trillion would be 30 planets in the universe with life!
Odds are, I'm being very conservative.
Hawking was Right (Score:2)
Nearly the speed of light? (Score:1)
Permit me a bit of scepticism regarding the "...at nearly the speed of light" statement. It's quite an achievement to get large (as in non-microscopic) quantities of matter to even 1/3 of the speed of light, even with the enormous energy of a supernova behind it. I don't think that most people would consider less than 1/2 of the speed of light to be "nearly the speed of light".
Re: (Score:2)
Still it's a pretty good speed. I was thinking about propelling tiny probes by placing them near a supernova, but then if you can get them near one in any reasonable amount of time it's not much better than your own sun blowing up...
Re: (Score:2)
I don't think that most people would consider less than 1/2 of the speed of light to be "nearly the speed of light".
Respectfully disagree. Consider (and apologies for the nonmetricism here): The speed of sound is pretty fast compared to most of what goes on around us. Mach 1 is roughly 0.2 miles/second. The speed of light is 1.86E5 miles/second, or Mach 930000 . On that scale, do we really want to call 1/2, or even 1/100 the speed of light "slow" or "near to the speed of light" ?
So what is fine tuned by this (possible) match up? (Score:2)
The stated (almost) speed of light,
the age of said sediments,
the distance of mentioned nova,
or the date of creation of Earth?
Re: (Score:2)
# We are stardust, we are golden, we are interstellar carbon...
Suprnova is gone (Score:4, Funny)
but piratebay and isohunt are still here
Iron 60 ? why not manmade ? (Score:1)
could also be due to that one : http://en.wikipedia.org/wiki/Ocean_disposal_of_radioactive_waste [wikipedia.org]
Re: (Score:2)
could also be due to that one : http://en.wikipedia.org/wiki/Ocean_disposal_of_radioactive_waste [wikipedia.org]
just because there's "isotope" there doesn't mean it goes hand in hand with nuke plants.
Re: (Score:2)
nope, reactor nuclear waste has iron-55, not iron-60. there is also cobalt-60 and nickel-63....