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Post by Red Rackham on Sept 4, 2023 12:14:31 GMT
Wait until you hear about gravitational time dilation. Time travels slower at sea level than it does at altitude because of gravity. If you spend 100 years on the top of Everest you will be 0.003 seconds older than a person who spent that time at sea level. It's one of the reasons I live in Suffolk. Time literally moves slower. Sadly, you only reap the benefits when you leave Suffolk and everyone else remarks on how youthful you look - those three missing femtosecond can make all the odds in a beauty contest held outside Suffolk. JoG, I know this is something of a digression however. I was recently listening to a diver who said qualified sport divers go as deep as 130 feet, but if the pool or lake they are diving is above sea level then the 130 ft figure is reduced due to the effect altitude has on the body, even underwater. I don't know why I was surprised by this tbh, it sounds perfectly reasonable. I mention this due to your background, I suspect it's something most people have never considered. Why would they, lol. |
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Post by Red Rackham on Sept 4, 2023 12:18:50 GMT
Red Imagine a ball falling towards the earth but also moving forward at (say) mach 10. If you increase the forward speed of the ball, at some point the earth's curvature becomes an issue. The ball falls, but the curved surface of the earth is also 'moving away' from the ball because it is curved. When the fall rate matches how quickly the earth's surface is 'retreating', then the ball is still (theoretically) falling but it never gets closer to the earth's surface because that surface is curved and the ball is moving forward. That's an orbit. The ball falls but perpetually misses the Earth. It must be said Orac, that was an excellent attempt lol, well done. |
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Post by Deleted on Sept 4, 2023 12:40:48 GMT
I understand what gravity is insomuch as I know a ball will roll down hill because of gravity. However, I don't understand why the moon circles the earth, I'm told it's because of gravity but the effects of gravity are far less in space than here on earth and besides, the moon isn't rolling downhill. Why are two rocks in space pulled towards each other? Gravity, oh boy. I remember watching Voyager 1 who used the gravitational pull of Jupiter as a 'slingshot'! I understand that gravity isn't magnetism, I just don't understand what gravity 'litterally' is. As you may have guessed, my grasp of astronomy would test the patience of the most understanding astrophysicist.  Notbody really fully understands it, which places a lot of it into the area of theoretical physics or particle physics (graviton). We just know (observation) that mass creates a dent in the fabric of space which pulls everything else toward it, which in turn compacts the atomic structure of all materials. |
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Post by besoeker3 on Sept 10, 2023 14:06:30 GMT
Billions of years ago, a version of our Earth that looks very different than the one we live on today was hit by an object about the size of Mars, called Theia – and out of that collision the Moon was formed.4 Oct 2022
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Post by besoeker3 on Sept 10, 2023 17:19:03 GMT
Test..................  |
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Post by johnofgwent on Oct 18, 2023 12:08:52 GMT
Sadly, you only reap the benefits when you leave Suffolk and everyone else remarks on how youthful you look - those three missing femtosecond can make all the odds in a beauty contest held outside Suffolk. JoG, I know this is something of a digression however. I was recently listening to a diver who said qualified sport divers go as deep as 130 feet, but if the pool or lake they are diving is above sea level then the 130 ft figure is reduced due to the effect altitude has on the body, even underwater. I don't know why I was surprised by this tbh, it sounds perfectly reasonable. I mention this due to your background, I suspect it's something most people have never considered. Why would they, lol. This is indeed the case I believe every 1000 ft you climb means water boils one degree centigrade lower because there is that much less air pressure on you. I am prepared to accept i have the figures wrong but the principle is right because i speak from personal experience that a cup of tea made at the cable car base station at mount teide tenerife tastes diabolical and coffee even more so and my pal who has stood at everest base camp and walked up to i think the first said tbe same of coffee from beans there. Tbe water bouls before it gets hot enough to do tbe job If you dive in a lake above sea level as i have done you had to reduce your bottom time in my case it cut the dive time in half The reason is all normal dive planning presumes the excess nitrogen you build up escapes into the blood as microbubbles as you ascend but is held in solution by a full atmosphere of 1000 millibars Scuba diving in a lake up a mountain the air pressure at tbe lake surface is less than 1000 millibars and depending on altitude could be a LOT less so the nitrogen bubbles firm faster and bigger. In our case we were doing pretty strenuous recovery of an item vandals dumped in keepers pond a fair height above blaenafon, tbe pond in question having been dug out of the mountain to hold mountain rainwater to fill the locks of the canal a thousand feet below … As you say people uninvolved with scuba diving would never make this association, but the fact you must is rammed home in the most basic of dive training courses. Because if it were not, someone doing it would certainly end up dead or hurt 130 feet (42 metres) is the absolute limit for sport air diving. I have been there for my instructor training. In the Canaries it is deep and unpleasant. In the UK it is stygian black and nothing short of gold bars for free would ever get me there. And you can only stay there for six minutes. |
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Post by johnofgwent on Oct 18, 2023 12:18:00 GMT
Lasers fired at certain bits of the moon reflect perfectly
Either
A) astronauts DID land there and leave mirror reflectors on tbe surface
B) the lasers are reflecting off the mother ship that lost some of its shuttlecraft at Roswell
Or
C) that’s no moon its a fully functional metallic space station
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Post by Red Rackham on Oct 19, 2023 11:52:33 GMT
JoG, I know this is something of a digression however. I was recently listening to a diver who said qualified sport divers go as deep as 130 feet, but if the pool or lake they are diving is above sea level then the 130 ft figure is reduced due to the effect altitude has on the body, even underwater. I don't know why I was surprised by this tbh, it sounds perfectly reasonable. I mention this due to your background, I suspect it's something most people have never considered. Why would they, lol. This is indeed the case I believe every 1000 ft you climb means water boils one degree centigrade lower because there is that much less air pressure on you. I am prepared to accept i have the figures wrong but the principle is right because i speak from personal experience that a cup of tea made at the cable car base station at mount teide tenerife tastes diabolical and coffee even more so and my pal who has stood at everest base camp and walked up to i think the first said tbe same of coffee from beans there. Tbe water bouls before it gets hot enough to do tbe job If you dive in a lake above sea level as i have done you had to reduce your bottom time in my case it cut the dive time in half The reason is all normal dive planning presumes the excess nitrogen you build up escapes into the blood as microbubbles as you ascend but is held in solution by a full atmosphere of 1000 millibars Scuba diving in a lake up a mountain the air pressure at tbe lake surface is less than 1000 millibars and depending on altitude could be a LOT less so the nitrogen bubbles firm faster and bigger. In our case we were doing pretty strenuous recovery of an item vandals dumped in keepers pond a fair height above blaenafon, tbe pond in question having been dug out of the mountain to hold mountain rainwater to fill the locks of the canal a thousand feet below … As you say people uninvolved with scuba diving would never make this association, but the fact you must is rammed home in the most basic of dive training courses. Because if it were not, someone doing it would certainly end up dead or hurt 130 feet (42 metres) is the absolute limit for sport air diving. I have been there for my instructor training. In the Canaries it is deep and unpleasant. In the UK it is stygian black and nothing short of gold bars for free would ever get me there. And you can only stay there for six minutes. Interesting stuff JoG. Some years ago I had an opportunity to learn scuba, and pot hole as it happens, I didn't fancy either. I used to know a chap who did both, I mean underwater potholing. The thought of squeezing into a flooded cave system is my idea of a nightmare. Climbing was scary enough for me. |
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Post by johnofgwent on Oct 19, 2023 11:58:22 GMT
I was trained to enter underwater wrecks etc. i never liked it, its the second easiest way to die while using scuba gear. There’s a reason it’s defined as ‘open water’ meaning nothing between you and the surface
But without doubt the craziest of the crazies are the cave divers.
All you need to know about how dangerous that is, is that one of the best trained elite in his field cave rescue guys DIED getting those kids out from what was almost their tomb
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