Questions about how fast the earth--or anything, for that matter--is moving are incomplete unless they also ask, "Compared to what? Consider the movement of the earth's surface with respect to the planet's center.
The earth rotates once every 23 hours, 56 minutes and 4. Thus, the surface of the earth at the equator moves at a speed of meters per second--or roughly 1, miles per hour. As schoolchildren, we learn that the earth is moving about our sun in a very nearly circular orbit. It covers this route at a speed of nearly 30 kilometers per second, or 67, miles per hour.
In addition, our solar system--Earth and all--whirls around the center of our galaxy at some kilometers per second, or , miles per hour. As we consider increasingly large size scales, the speeds involved become absolutely huge! The galaxies in our neighborhood are also rushing at a speed of nearly 1, kilometers per second towards a structure called the Great Attractor, a region of space roughly million light-years one light year is about six trillion miles away from us.
This Great Attractor, having a mass quadrillion times greater than our sun and span of million light-years, is made of both the visible matter that we can see along with the so-called dark matter that we cannot see. Each of the motions described above were given relative to some structure.
Our motion about our sun was described relative to our sun, while the motion of our local group of galaxies was described as toward the Great Attractor.
It's an idea I've touched on in other articles, but today I want to focus on it specifically:. Space is about kilometers away. That's far away—I wouldn't want to climb a ladder to get there—but it isn't that far away. Getting to space [1] Specifically, low Earth orbit, which is where the International Space Station is and where the shuttles could go. It's not, like, something you could do in your car, but it's not a huge challenge.
You could get a person to space with a small sounding rocket the size of a telephone pole. The X aircraft reached space [2] The X reached km on two occasions, both when flown by Joe Walker. Gravity in low Earth orbit is almost as strong as gravity on the surface. To avoid falling back into the atmosphere, you have to go sideways really, really fast. The speed you need to stay in orbit is about 8 kilometers per second.
Only a fraction of a rocket's energy is used to lift up out of the atmosphere; the vast majority of it is used to gain orbital sideways speed. This leads us to the central problem of getting into orbit: Reaching orbital speed takes much more fuel than reaching orbital height.
Reaching orbital speed is hard enough; reaching to orbital speed while carrying enough fuel to slow back down would be completely impractical. Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots. Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe.
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