Changes in Earth's Orbit Linked to Extinctions

Josh Fink writes "A group of Dutch Scientists have recently released a study stating that they have found that changes in Earth's orbit around the sun are linked to mammal extinctions. From the article: '"Extinctions in rodent species occur in pulses which are spaced by intervals controlled by astronomical variations and their effects on climate change..." The cycles are associated with lower temperatures, changes in precipitation, habitats, vegetation and food availability which are the main factors influencing the extinction peaks, the study published in the journal Nature said.' So on top of worrying about global warming, it seems we should also worry about the physics that govern the orbit of Earth around the sun. Too bad we don't have a way of keeping the Earth in the same orbit/on the same axis of rotation."

Comments

BTW

[hamburger lady]

before anyone starts getting all 'see, all you global-warming believers, this is a perfectly rational natural explanation for the current warming trend,' the periods of these natural cycles are on the order of 1.2 and 2.4 million years. not exactly fast-acting.

Re:BTW

[mwlewis]

Then there's the fact that North-West Europe (in particular us Brits) is kept warm by the Gulf Stream (look it up)

OK. I think you'll find that there is some doubt about this.

Re:BTW

[FhnuZoag]

Man, why do people like you just draw random assertions out of a hat and pretend that's the divine truth. Let's actually look at the science, eh?

http://en.wikipedia.org/wiki/Permian-Triassic_exti nction_event

70% of all vertebrate species died in under a million years, leaving fungi dominant. Something of a mass extinction event, eh? (In fact, Earth's worst mass extinction event.) Observe the big temperature spike at PETM. (Top right corner)

http://upload.wikimedia.org/wikipedia/en/1/1b/65_M yr_Climate_Change.png

Thank you and goodnight.

Vague article

[novus ordo]

More info in nature. It seems to do with something called Milankovich cycles. But i guess 'wobble' is specific enough for stuff that matters.

Re:Move Along

[guycouch]

Here's a quick link to some other studies: http://earthobservatory.nasa.gov/Study/Paleoclimat ology_Evidence/

Re:Move Along

[AviLazar]

Or....people, w/o a clue, are reading this and blowing it out of proportions by not keeping it in context. Changes to our atmosphere, because of orbital deviance, happens in the millions of years category.....changes in our environment, due to global warming is happening on a monthly/yearly basis.

So yea, if I edited portions of the article I could make it sound like the orbit change is the reason for global warming.... then again, if i took bits and pieces of the quoran (sp) I could tell people that Allah demands we kill anyone who is not muslim, even if it means we have to kill ourselves to do it.

Moral of the story: Use the whole story, and keep it in context.

Freaked out

[wurp]

The whole tone of this /. post freaked me out. There's no way for there to be 'irregularities' in the Earth's orbit without something with both really high mass and really high velocity interacting with the earth or the sun.

So I read up on Milankovich cycles, and it turns out it's just precession. It's perfectly regular, it's just that in the case of something the size & slow angular velocity of the earth, it takes a really long time to change.

When you spin a top, you can see the axis of spin describe a circle. This is precession.

Likewise as the Earth rotates, there is precession. Also, as the earth orbits the sun, there is precession. These have cycles on the order of tens of thousands of years. Both can affect the climate by changing the angle of sunlight. There are cycles on the order of millions of years long in which the two effects both affect the climate the same way, and so produce a bigger net effect.

I guess wobble is an accurate term, except that to me it implies something irregular. In a system as big and isolated as the Earth's orbit around the Sun, or the Earth's rotation, momentum is king, and very little could cause an irregular change. These changes are just precession, and they're perfectly regular.

I am not a physicist, but I do have a Bachelor of Science in Physics.

Re:The people of China can save us....

[Brickwall]

figuring a mere 60lbs per person, the 78,838,422,780 pounds landing on one side of the planet should have quite an effect.

Converted to kilograms, your figure works out to 3.5 * 10^10 kgs. Let's triple the weight to 180 lbs, and your figure becomes 1 * 10^11 kgs.

Now, the mass of the earth is approximately 6 * 10^24 kgs. That's 6 * 10^13 bigger. Let's see what a similar ratio would look like applied to a 100 kg (220 lbs) human. Something that is 10^13 smaller would be approximately 1 microgram. The average piece of dust weights about 100 micrograms.

So the effect would be like an exceptionally tiny piece of dust striking you, i.e. no effect at all.