A facinating simulation of what would happen if a Sun sized object passed through the solar system.
Tag: solar system
The End of the Earth
The Earth will end with fire, non-metaphorically. It will be consumed when the sun expands as it runs out of fuel, 5 billion years from now.
The History of the Moon
In the early solar system, 4.5 billion years ago, the planets were still coalescing, something enormous hit the Earth.
After it formed, huge impacts shaped the surface of the moon into what we see today. NASA takes up the story:
These videos are awesome introductions to the early history of the Earth, Moon, and solar system.
Terraforming Mars
Jason Shankel has an article on how we could go about changing the surface of Mars into something humans can live on. He does an excellent job of condensing the not insignificant literature on terraforming the red planet.
Starting with an explanation of Mars’ geologic history, Shankel addresses Martyn Foggs’ list of critical challenges:
- The surface temperature must be raised
- The atmospheric pressure must be increased
- The chemical composition of the atmosphere must be changed
- The surface must be made wet
- The surface flux of UV radiation must be reduced
— Shankel (2011): How We Will Terraform Mars on io9.com.
The article is expansive in its detail, provides a wonderful primer on the red planet, and demonstrates an excellent application of planetary system science (as opposed to Earth system science) to what would be an enormous geoengineering project. For example, to warm up the planet, Shankel starts with several approaches:
so how do we warm up the Martian poles? Several approaches have been suggested, from spreading dark material on the poles to lower their albedo, to industrial ice farming to good old fashioned thermonuclear detonations.
— Shankel (2011): How We Will Terraform Mars on io9.com.
He then goes into detail. Lots of detail, in a quite readable form.
Build Your Own Solar System: An Interactive Model
National Geographic has a cute little game that lets you create a two-dimensional solar system, with a sun and some planets, and then simulates the gravitational forces that make them orbit and collide with each other. The pictures are pretty, but I prefer the VPython model of the solar system forming from the nebula.
The models starts off with a cloud of interstellar bodies which are drawn together by gravitational attraction. Every time they collide they merge creating bigger and bigger bodies: the largest of which becomes the sun near the center of the simulation, while the smaller bodies orbit like the planets.
This model also comes out of Sherwood and Chabay’s Physics text, but I’ve adapted it to make it a little more interactives. You can tag along for a ride with one of the orbiting planets, which, since this is 3d, makes for an excellent perspective (see the video). You can also switch the trails on and off so you can see the paths of the planetary bodies, note their orbits and see the deviations from their ideal ellipses that result from the gravitational pull of the other planets.
I’ve found this model to be a great way to introduce topics like the formation of the solar system, gravity, and even climate history (the ice ages over the last 2 million years were largely impelled by changes in the ellipticity of the Earth’s orbit).
National Geographic’s Solar System Builder is here.