Long time lurker, finally registered to post a question:
Using technology available during the next 100-200 years, would it be possible for mankind to somehow move the Earth closer to the sun, whether purposely or not? Alternately, what could man do to turn the entire landmass of the planet into a desert?
We’ve had a number of discussions about the possibilities of moving the planet. You should try searching. You can use Google and limit the search to site:straightdope.com.
There are ways of doing so, but they are nowhere within any technologies of the next few hundred years. Moreover, they would take enormous amounts of time to have any effect. Which is a good thing. A magic beam to move the earth would kill everybody on the planet, unless it really were magic.
Just out of curiosity, why would you want to earth to be all desert? And how would humanity live there if it was?
Can we at least move it close enough that we don’t have that annoying 1/4 day left over at the end of the year?
It would probably be easier to slow the Earth’s rotation by 0.3% to make a day actually equal to 24 hours. Similarly, if you want to effect significant climate change, altering the Earth’s axial tilt relative to the ecliptic would make a more dramatic impact for less impulse. Regardless, short of packing on a lot of external mass or dragging a large moon in close intercept to the Earth repeatedly, there is no extant technology, even conceptually, to measurably alter the Earth’s orbit or rotation.
Can we turn the landmass into a desert? That is (relatively) simple. Pumping enough CO[sub]2[/sub] into the atmosphere, trapping in heat from solar energy flux should be sufficient to prevent water from condensing on the surface. Of course, we’re talking a lot of CO[sub]2[/sub], even more than every man, woman, and toddler on Earth commuting from Los Angeles to New York on a daily basis could pump out. But the effect, once you get it going, should be self-reinforcing, blocking out sunlight and preventing the normal photosynthetic processes that break down carbon dioxide and fix nitrogen from occurring. Turning the Earth into a tundra is even easier; take a largish asteroid, grind it into dust, and start building a solar shield at the L1 libration point between the Sun and the Earth, with a large keel to keep it stable, shielding part or all of the Earth in its umbra. As the radiant energy is reduced, the atmosphere will grow cooler and less able to hold water, and atmospheric water will condense on the surface as ice.
Stranger
How are you going to build a Fremen army without a desert planet? Hmmmm???
Please consider using Mars before unilaterally deciding to turn Earth into a desert planet.
Maybe it was a typo and the OP meant to turn Earth into a dessert planet.
Or would that just attract Galactus?
The average day is much closer to 24 hours than 0.3%. Over the ~40 years since the introduction of leap seconds, it has only been necessary to insert 24 leap seconds, less than one per year. Currently, the average day is less than 1 millisecond longer than 24 hours or about 1 part in 10^8, so 0.000001%.
While it’s true that it would take enormous amounts of time, it isn’t true that it would take technology that far in advance of what we have now. All you need to do is arrange for a large asteroid to make repeated close passes to Earth and the gravitational interaction will slowly drag the planet the way you want.
Sounds like someone’s been watching Frisky Dingo!
In the first season of Frisky Dingo, the “antagonist” (Killface) builds a giant rocket on the surface of the Earth, which he intends to use to push the Earth into the sun. However, in the final episode of the season, the “protagonist” (Xander Crews) turns on the Annihilatrix at the wrong time, pushing the Earth several feet further from the sun. In the second season, Killface runs for POTUS using the claim that he solved global warming.
How do we move the asteroid?
JWT Kottekoe, he meant to make one day exactly equal to 1/365th of a year.
I’m writing a story that hinges on humanity having caused a massive disaster that makes a majority of the planet uninhabitable. A key point in the story is that natural rain is very rare, so I though desert (not dessert, Exapno, although that would be an interesting story, also).
I was thinking climate shift, but am open to other ideas. Stranger mentions an excess of CO2. Could industrial pollution reach a point where it rendered the earth nearly uninhabitable? Or maybe a giant industrial accident? Are there any technologies within the reach of the next 100-200 years that could have disastrous consequences?
…which is vastly beyond any extant propulsion technology.
Stranger
Eh, you could probably do it today, if you were really patient and had the funding. Send a probe out into the Kuiper belt or Oort cloud, and intercept a comet at aphelion. A very small change in the velocity at aphelion will result in very large changes in the orbit and its behavior near perihelion. Lather, rinse, repeat for multiple comets (or even the same one repeatedly). The only real technological difficulty would be in building the probe so it could last the hundreds or thousands of years needed.
The scientists who came up with the idea said that plain old chemical rockets would work. Nuclear would be better I presume. Remember, this isn’t a divert-the-incoming-impact scenario; you don’t need to be quick about it.
Or just build a space infrastructure to support the asteroid moving drive. After all, if you are going to do a project that takes thousands (millions?) of years you certainly have the time.
What scientists? How do we [del]move[/del] affect and direct the motion of an asteriod that is itself massive enough to appreciably affect Earth’s orbit?
A NASA research group I believe.
Slowly I presume. The asteroid in question only needs to be around 100k in diameter; huge, yes, but minuscule compared to a planet. And again, you only need to move it slowly. The simple fact that it lacks an atmosphere makes it far easier to move since you can use rockets.
I meant “by what mechanism,” not “in what fashion.”
And by the time that was done by the method you’re speaking of, the climage would have changed eight or nine hundred times.
Each time the asteroid passes its gravity tugs very slightly at the Earth (so, yes, the pass needs to be a close one - don’t make any mistakes). Do this enough times and the planet will slooowly move to a new orbit.
They proposed it as a method of preserving Earth for a few extra billion years from the long term warming of the Sun. We’re talking preventing Earth being turned into Venus 2, not relatively minor climate swings. Since I understand we’d probably lose the Moon in the process you’d get climate changes anyway.