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Speed: 600 mi/hr (1,000 km/h or 0.27 km/s) |
Speed: 25,000 mi/hr (40,000 km/h or 11 km/s) |
Speed: 186,000 mi/sec (300,000 km/s) |
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The table above is much more than a chart of travel time, it represents a glimpse into the past. When you look into the night sky you are looking into the history of the universe. The sunlight that shines on us is 8.5 minutes old when it reaches Earth. Sunlight reflected from Pluto takes 5.5 hours to reach the astronomer's telescope. When the light of Sirius hits your eye, those photons have been traveling for over 8 years through space. This means you are seeing that star not as it is tonight but as it was over 8 years ago. And most of the stars we see in the sky are hundreds or thousands of light years away. The Andromeda galaxy, at a mere 2.5 million light years, is truly a next door neighbor. All of the other galaxies are millions upon millions of light years distant. And that's how big the universe is.
The numbers are only rough estimates and assume the celestial bodies are not in motion for the sake of ease of calculation.
The unit mile
There are two different miles: The statute mile (1) and the nautical
mile (2).
1) The statute mile is defined by US-law: 1 statute mile is about 1.609
km. This is the unit you use for car traffic (mph, ...).
2) The nautical mile is related to the perimeter of planet Earth and
is the length of 1 arcmin of the Earths perimeter.
1 nautical mile is about 1.852 km. (40,000 km / 360° / 60')