A perspective of distances in space

This video has been making the rounds lately. It is a view of the sun, the camera moving back at the speed of light – illustrating in realtime, the journey of a photon of light emitted from the surface of the sun and traveling across a portion of the solar system – from a human perspective.

The animation ends at Jupiter Even so, it certainly illustrated to me that interplanetary travel is going to get extremely boring without lots of things to occupy the travellers. They won’t be travelling this fast.

Riding Light on Vimeo

Credit: Thanks to RT: Seeing stars: Traverse Solar System at speed of light

Phil Plait gave another perspective of distances in space in his article Can You Really Fit All the Planets Between the Earth and Moon?

He answers the question with a Yes – sometimes!

planets_linedup.jpg.CROP.original-original

At most times the planets just do not fit.

But:

At apogee, when the Moon is farthest from the Earth, the center-to-center distance is more like 406,000 km, so about 398,000 km surface-to-surface. Aha!

At lunar apogee, the planets do fit, rather comfortably. And there’s more: I used the average diameters of the planets. Most of the planets are not spherical, but due to their rotation they’re oblate, or squashed; smaller in diameter through their poles than across their equators. We can make them fit better if we align them through their polar axes. That total distance is 364,799 km. That’s still too much if the Moon is at perigee, but gives us a little more breathing room when the Moon’s at apogee.

Finally, we can look at the average distance of the Earth to the Moon, which is 384,400 km, or 376,000 km surface-to-surface. In that case the planets fit if we align them pole to pole, but not using their average diameters.

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3 responses to “A perspective of distances in space

  1. They could spend their time contemplating the possibilty of remote viewing. http://www.biomindsuperpowers.com/Pages/CIA-InitiatedRV.html

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  2. David Fierstien

    If you were travelling at the speed of light, looking at the sun, would you even be able to see it? As you moved away from the sun at that speed, new light emitted from the sun could never catch you.

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  3. David Fierstien

    To answer my own question, if you left the sun at the speed of light it would be invisible. If you slowed down to just below the speed of light it would appear very red because of the Doppler Shift (light waves would be lengthened to the red end of the spectrum) and no matter how far out you were, assuming you had been traveling at the speed of light, you would see the sun from just a few seconds after you left. As you approached the planets they would appear blue because the light would be compressed. After you passed them they would become invisible or red as you slowed down.

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