Middle and High School … from a Montessori Point of View
NASA thinks their rover has found veins of gypsum on Mars. If they have, it will be an excellent indication that there was once standing water on Mars — gypsum is usually precipitated in evaporating lakes — and will excite the search for life on Mars.
The Voyager 1 spacecraft is rapidly approaching the space between the stars, where the Sun’s solar wind is pushed back by the interstellar magnetic cloud.
How far will it go? The spacecraft have enough power to last until 2020, when it will be about 20 billion kilometers from the Sun (it’s now about 17.8 billion km away). In 40,000 years it will drift “within 1.6 light years … of AC+79 3888, a star in the constellation of Camelopardalis” that’s about 17.6 light years away.
Consider the 40,000 years it will take Voyager to travel 17.6 light years, and the distance to Keppler 22-b, a recently discovered “Earth-like” planet that’s about 600 light years away.
Keppler 22-b is in the liquid water zone of it’s solar system: far enough away from its sun that water on its surface will not just boil away from the heat, yet close enough that the water does not just freeze solid instead. Liquid water is a key necessity for all life as we know it.
The galaxy cluster MACS J1206. Galaxy clusters like these have enormous mass, and their gravity is powerful enough to visibly bend the path of light, somewhat like a magnifying glass.
These so-called lensing clusters are useful tools for studying very distant objects, because this lens-like behaviour amplifies the light from faraway galaxies in the background. They also contribute to a range of topics in cosmology, as the precise nature of the lensed images encapsulates information about the properties of spacetime and the expansion of the cosmos.
–NASA, ESA, M. Postman (STScI) and the CLASH Team: Hubble image of galaxy cluster MACS J1206
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.
Water is necessary for life as we know it, which is why the search for life on other planets and moons in the solar system has been focused first of all on finding water. NASA now reports signs of water on Mars. Salty water perhaps, and even now there is no direct evidence that it is water and not some other fluid, but this is the first evidence of there being liquid water on Mars today.
The video above explains, and the BBC has a good article.
The last re-entry of the space-shuttle was captured from the International Space Station.
Here’s a neat little video, which holds the Milky Way (galactic-centric) steady as the Earth rotates relative to it.
For comparison, here’s the original video by Stephane Guisard and Jose Francisco Salgado, showing the geocentric view of the sky moving:
It is always revelatory to see things from unexpected perspectives. Brian Swimme was amazed by the immensity of it when he first truly recognized that he was standing on a planet that was rotating through space orbiting the Sun.
I’ve always been struck by the opposite point of view. To think that if you hold still enough, and think about it a bit, from one point of view you could be the central reference point for the entire universe, with everything else moving relative to you: the Earth still beneath your feet; the Sun (almost) orbiting around you; and the planets arcing through their epicycles.
Except that you can hear the dust and small rocks banging on your spacecraft.
from JPL.