The End Not As Near As We Thought

HiyaPower writes: "According to recent calculations cited by this article in TheAge, the calculations that the sun would expand to a red giant and engulf the earth are wrong. It will expand, but due to the loss of solar mass over time due to the conversion of mass into energy, the earth will spiral enough further away thus avoiding the fate of Venus and Mercury. Personally I find this a great relief, I had some long term plans that I had been putting off..."

Comments

Please

[Anonymous Coward]

We will blow ourselves up LONG before that ever happens.

Re:Not to be cynical, but...

[glwillia]

This matters why? I mean, sure, they have to update the textbooks, but why is this worth researching, let alone newsworthy? Can this problem help us solve other problems that need to be solved?

Any astrophysicists mind?


Well, as a budding astrophysicist (undergrad physics/astronomy major at UofA), planetary/stellar evolution is quite an important area of research (in fact, a whole branch of astronomy focuses on this. It's even a separate degree program at some schools--planetary science). Also, forgetting to account for the radiation of energy and the resultant decrease in mass seems to be a fairly major oversight, in violation of some of the most basic concepts of orbital motion, such as the fact that the downward force due to gravity (and, hence, responsible for the behavior of orbits) is proportional to the mass of the central object and inversely proportional to the radius squared. Decrease the mass, and the force decreases, resulting in a change in the dynamics of Earth's movement, and increasing the perihelion and aphelion.

This is worth researching because Earth and its fate is somewhat important to us, for reasons that should be obvious. This will help us model the evolution of the solar system up to the white-dwarf stage, one which will be reached by most main-sequence stars (we think).

Re:I wouldn't put too much hope in this

[LadyLucky]

I have to debunk one of these:

When the polar ice caps melt, the ocean level does not rise. Why? because as ice they displace the same amount of space as they would if they were water. It is achimedes' principle. It is what keeps ships afloat, what makes submarines work. Consequently, melt ALL the polar ice caps and our friends in The Netherlands wont notice a thing.

This came from a piece of mistaken research earlier last century by the EPA, where they forgot this. It was an honest mistake, since owned up to, but that has not stopped it entering the public mind, and assorted do-gooders still using it for shock value.

One thing that can get us is if the ice on the Antarctic continent melts. This is possible, but highly unlikely. Ever opened your freezer on a hot day? Do you get more or less ice? That is probably not a concern.

So what are the possible problems? is the ocean level rising? Yes, it is. It rises naturally over time due to sedimentation processes, about 20cm/century, IIRC. The thermal expansion of water due to global warming (supposedly, see the ATOC project for more info) is likely to add a similar amount.

One hopes to disillusion one more person every day....

Re:I wouldn't put too much hope in this

[pmc]

When the polar ice caps melt, the ocean level does not rise. Why? because as ice they displace the same amount of space as they would if they were water. It is achimedes' principle.

Oft stated, but actually wrong (even ignoring the fact that some polar ice is on land). When the ice melts it melts for a reason - the sea has warmed up. And when the sea warms it will expand. See this Nature Abstract or even from USA Today

Re:At least we'll have time to prepare

[buckeyeguy]

I won't go down the doom route, but I'll simply say that it's _far_ from a foregone conclusion that humans will be around even a million years.

OK, I'll go down the doom route for you ;). Even if we assume that local effects (stability of the sun, earth, orbits of other planets) are predictable and non-threatening (big assumption in itself), the chances are very high that another large-body collision will occur before then (like the one that is theorized to have caused the dinosaurs' extinction event 65 million ago). Also, in round numbers, we've got about 25-30 more revolutions around the center of the galaxy... plenty of chance for interaction with other stars or extra-solar bodies. Then there's intergalactic interaction... I forget what the latest estimate is, but Andromeda (M31) is supposed to pay us a visit sometime before 5 billion years is out.

Or, some asshole will push the button, and we'll leave the roaches and telemarketers to ponder the whole thing.