Supernova Left Its Mark In Ancient Bacteria

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."

Comments

Bacteria

[Tyler R.]

"iron-loving bacteria" mmmm.....radioactive iron..... :D

Maybe it woul be...

[Anon, Not Coward D]

an interesting evidence about some "recent" mass extintion event:

http://en.wikipedia.org/wiki/Mass_extinction#Lesser_extinctions

Re:Maybe it woul be...

[lw7av]

I only have 2 questions regarding this: when did this happen? And how far away from the blast where we?

Re:Maybe it woul be...

[Anonymous Coward]

A lot of (maybe most of?) the mass extinction events were caused by supernovas. Google "supernova mass extinction" and you'll get reams of returns of many extinctions tied to supernovas. I used this event to bring a little science to the book I'm writing. (table of contents here, mention of the Ordovician-Silurian extinction event is in one of the two chapters not yet posted; "Farmers on Drugs").

When I researched wikipedia for realism, I discovered that these extinction events (the ones caused by supernovas) didn't kill the species by radiation, as I'd supposed, but by burning up much of the atmosphere's nitrogen, causing smog and destroying the ozone layer. So the supernova in the book is a man-made supernova that destroys the Acrux system 300 light years away in the Southern Cross; two warring planets construch neutron stars to swallow their enemies' solar systems, and the two weapons collide.

Science fiction should have science, and there's a lot in the book. Lots of chemistry and physics as well as astronomy. But this subject, the supernova-caused mass extinction, is pretty much incredibly interesting to me right now because I've been researching for the book and learned a hell of a lot. I'm hoping some more slashdotters more knowledgable about these fields than me will point out any retarded stupidities in the story (it's already happened, one that was a really stupid Scotty from ST4 millions-thousands error).

I wish I'd have seen this story when I was logged in. It will be too old before I can log in again.

I'm not saying it's aliens, but...

[DougOtto]

it's aliens.

One supernova of many in Local Bubble

[Morgaine]

Our solar system resides in an area of our galaxy called the "Local Bubble", 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" 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. It's a fascinating subject if you enjoy understanding our location in a galactic context.

Re:One supernova of many in Local Bubble

[Anonymous Coward]

That's interesting, but they haven't really linked this to a specific nova, but to a group of stars 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:One supernova of many in Local Bubble

[Anonymous Coward]

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 actually alludes to the Fe-60 research as well.

Re:One supernova of many in Local Bubble

[argStyopa]

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:One supernova of many in Local Bubble

[Anonymous Coward]

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 temperature gradient keeping these chemicals in a proper state.

Re:One supernova of many in Local Bubble

[smpoole7]

> 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:One supernova of many in Local Bubble

[Anonymous Coward]

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, both would have raised the frequency of material reaching our surface, sometimes catastrophically.

Under such conditions, the probability of cosmic extinction events for a planet with life is clearly higher than at present. The current (6th) mass extinction event is orders of magnitude worse but it does not have a cosmic cause, being man-made, so it's not germane to the emptiness of the Local Bubble.

Our disastrous custodianship of the planet aside, there was no shortage of cosmic threats to the survival of our biosphere not long ago.

Re:One supernova of many in Local Bubble

[Anonymous Coward]

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:One supernova of many in Local Bubble

[Anonymous Coward]

Multicellular life requires abundant oxygen for collagen. To get oxygen, you need photosynthesis. On our planet, there is no evidence for multicellular life until 800-500m years ago. And it took 2B years to get oxygen into atmosphere through photosynthesis.

http://en.wikipedia.org/wiki/Timeline_of_evolution
http://en.wikipedia.org/wiki/Great_Oxidation_Event

Once you get multicellular life, the rest is mostly evolution. If humans didn't appear now, perhaps another creature would appear later. There are some very smart ones out there aside from apes, or even mammals.

Basically, water + light + time yields intelligent life. But all multicellular life as we know it requires oxygen. And the longest step for Earth was getting oxygen, not actual evolution once we had oxygen. We know that Earth has at least another 100m years until it gets too hot, possibly more so this time is not exactly "unique".

Now, saying that there is other intelligent in our galaxy at exact same development level should be rare. But that does not mean that intelligent life is rare. +- 1B years is more than enough time to turn bacteria into people once you have oxygen. +- 1 or +-2B years from now, there could be thousands and thousands of civilizations around our own galaxy. Then we have trillions of galaxies out there...

It is our timescale of human lives that is problematic. Look at 150 year old science books and how much we have advanced. From "canals on Mars" to rovers on Mars.. Simply because we didn't find any life out there in last few years, does NOT indicate there is no life. For all we know, the universe is crawling with it and they are watching this planet, learning just like we learn by watching rats in a maze. Heck, I would if I was them I would do exactly that - no, you do not want to step into an anthill you are studying!

Re:One supernova of many in Local Bubble

[houbou]

Consider this: 30 billion trillion (3x10) stars in the visible universe. (estimated as of 2006).
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.

Re:One supernova of many in Local Bubble

[Anonymous Coward]

But all multicellular life as we know it requires oxygen.

ORLY?

Apparently not.

And that was just the first result searching for "anaerobic multicellular organism"....

Re:One supernova of many in Local Bubble

[Anonymous Coward]

The Earth gets blasted by supernovas, and all we get is some minor deposits in a geological layer.

Google says you're wrong. Supernovas have caused many mass extinctions, including The second-largest extinction in the Earth’s history, the killing of two-thirds of all species, may have been caused by ultraviolet radiation from the sun after gamma rays destroyed the Earth’s ozone layer.

Re:One supernova of many in Local Bubble

[Anonymous Coward]

Bases on my Master of Orion experience, a local bubble spells certain doom to our species because it delays colonization of other star system, and makes us inferior to other, mult-star civilizations. It temporarily keeps us out their reach, but that is a false sense of security. As soon as they develop ion trusters and tachyon communication we are doomed. We need an orbital base equipped with Class III shield and particle beams ASAP!

Re:One supernova of many in Local Bubble

[Anonymous Coward]

Based, not bases. Damn cell phone communicator!

Hawking was Right

[alphatel]

We better get the hell out of this damn quadrant!

Nearly the speed of light?

[Anonymous Coward]

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:Nearly the speed of light?

[GameboyRMH]

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:Nearly the speed of light?

[cellocgw]

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?

[Mister Liberty]

The stated (almost) speed of light,
the age of said sediments,
the distance of mentioned nova,
or the date of creation of Earth?

3 Million Years Ago

[Anonymous Coward]

Climate changed, East Africa dried up and savanna formed. Our ancestors likely started running their pray to death. Would a supernova cause such a climate change? It's a long shot, but it would be fun to be called the children of supernova, in an new agy, ufo nutt..hunting enthusiast sort of way.

Re:3 Million Years Ago

[Hognoxious]

it would be fun to be called the children of supernova

# We are stardust, we are golden, we are interstellar carbon...

Suprnova is gone

[Spy Handler]

but piratebay and isohunt are still here

Rust

[Taco Cowboy]

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

Iron 60 ? why not manmade ?

[stooo]

could also be due to that one : http://en.wikipedia.org/wiki/Ocean_disposal_of_radioactive_waste

Re:Iron 60 ? why not manmade ?

[gl4ss]

could also be due to that one : http://en.wikipedia.org/wiki/Ocean_disposal_of_radioactive_waste

just because there's "isotope" there doesn't mean it goes hand in hand with nuke plants.

Re:Iron 60 ? why not manmade ?

[iggymanz]

nope, reactor nuclear waste has iron-55, not iron-60. there is also cobalt-60 and nickel-63....

Supernovas

[Anonymous Coward]

I wonder if I can blame them for this unexplainable rash I have...

Silly Science

[Anonymous Coward]

Does the science cult not realize that the earth is about 6,000 years old. This "supernova" garbage is merely a fairy tale.