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Author
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Topic: Explaining why there is no 'up' in space
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Buel
Member Posts: 748
From: UK
Registered: Mar 2012
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posted 02-23-2021 03:07 AM
   
I was showing an Apollo 8 photo of Earthrise to some work colleagues yesterday online and I tried to explain why the "Which way is up?" question regards to Earth is asked a lot. I explained that there is no "up" in space but I couldn't explain it as well as I wanted to.Anyone care to lend a hand at this? |
OLDIE
Member Posts: 300
From: Portsmouth, England
Registered: Sep 2004
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posted 02-23-2021 04:06 AM
Maybe it's because virtually all maps are drawn taking north as being at the top of the map. I don't know why, or when, this concept first was adopted. Possibly a historian or cartographer could explain. Thus, in space, we expect the Earth to look as it does in atlases. Otherwise its "upside-down." |
Buel
Member Posts: 748
From: UK
Registered: Mar 2012
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posted 02-23-2021 04:25 AM
Brilliant. |
oly
Member Posts: 1181
From: Perth, Western Australia
Registered: Apr 2015
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posted 02-23-2021 04:26 AM
Because there is no down.On Earth, we have a down reference because Earth's surface counteracts the force of gravitational attraction. This sensation of gravitational attraction is referred to as down, and its opposite is identified as up. In Earth orbit, bodies are considered to be in a constant state of freefall because the rate of falling is matched by the velocity vector. As there is no longer a sensation of the downward attraction, there is no longer a down reference, so there is no longer an up. Lunar orbit works the same, however, as the Moon is the dominant gravitational influence, the required velocity to maintain orbit is much lower. There is no down reference during orbit, so there is no up reference. So without a down, there is no up. Looking out of a spacecraft window, the natural tendency is to reference Earth or the lunar surface as down due to visual cues, because our norm is to use up as the opposite of down, we could consider that the Moon should be at the lower position within the Apollo 8 Earthrise image if we reference the Moon as being down. If we reference Earth in the image as being down, then up would be behind the Earthrise audience. I believe that the Earthrise image up/down reference is traditionally made against the command module Y-axis when the image was captured. |
Joel Katzowitz
Member Posts: 833
From: Marietta GA USA
Registered: Dec 1999
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posted 02-23-2021 07:20 AM
As an aside, I was photographing the walkout for STS-80 back in 1996. When I got the slides back I noticed that Story Musgrave had the name tag (Story) on his flight suit oriented upside down. Several years later I spoke with him at an event and asked him why, he simply replied "because there's no up in space." Later I sent him a print of that image and asked him if he would sign it for me upside down, he did. |
oly
Member Posts: 1181
From: Perth, Western Australia
Registered: Apr 2015
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posted 03-05-2021 07:11 PM
Here is some additional information on the subject: |
Altidude
Member Posts: 81
From:
Registered: Jan 2016
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posted 03-06-2021 11:08 AM
Early maps typically had a "up" direction pointing east, that is why the Sanskrit word for right is the same as south. That makes sense because it was in the direction of the rising sun. Egypt took a different route and put south as "up" and that's why you have the upper and lower kingdoms which refer to the flow of the Nile. I read somewhere that some of the Viking invaders of England used southward pointing maps in their invasion of England. The Arabs very commonly used South pointing maps. But basically, with Magellan and the European discoveries, their mapmaking fell into favor and now we have north as up. Hope this helps. |
Jonnyed
Member Posts: 478
From: Dumfries, VA, USA
Registered: Aug 2014
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posted 03-20-2021 07:44 AM
quote:
Originally posted by Altidude:
Early maps typically had a "up" direction pointing east, that is why the Sanskrit word for right is the same as south. That makes sense because it was in the direction of the rising sun.
Yes, the east orientation is how the term "the Orient" became identified with the Asian continent. Up, Down in space?... "It's all relative." |
Cooper95
New Member Posts: 5
From: Omaha, Nebraska,USA
Registered: Mar 2021
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posted 03-22-2021 11:43 AM
Space is such a difficult thing, if I may say so, of course. I always thought that North is 'up,' but in space... everything is different, everything. In space, up and down is almost everywhere. |
Altidude
Member Posts: 81
From:
Registered: Jan 2016
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posted 03-22-2021 08:39 PM
In all respects, north being up does make sense (as does south). All the planets basically rotate around the sun on the same axis as does the moon around Earth. This kind of breaks down when you get to Uranus, though. Wait... did that sound bad? |
Gordon Eliot Reade
Member Posts: 77
From: Palo Alto, Calif.
Registered: Jun 2015
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posted 03-23-2021 11:24 AM
Way back in the 1940's someone asked Arthur Clarke how an astronaut would navigate in space, what with there being no up or down. Clarke said, imagine a pilot who takes off from one aircraft carrier and lands on another. For take off he orients himself by the flight of the first aircraft carrier. In flight it might fly by reference to a magnetic compass. For landing he’d fly by reference to the deck of the second carrier. The challenge I have is at public star parties someone might ask why the rings of Saturn are tilted when they are shown as horizontal in the textbook. Or they might ask why they are tilted at a different angle from the next telescope over. |
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