Soldato
Nice. Thank you.
Now if we half the radius, it needs to be 4 times faster just to have the same effect it has now right?
A question about giant pterosaurs taking off.
- Thread starter Angilion
- Start date
Nice. Thank you.
Now if we half the radius, it needs to be 4 times faster just to have the same effect it has now right?
Don
If we half the radius and quadruple the speed of rotation we have 8 times the effect.
Halving the radius means we have to increase the speed by approximately 1.4 times to get the same effect.
It's all about rate of change of angle vs linear speed.
Halving the radius means we have to increase the speed by approximately 1.4 times to get the same effect.
It's all about rate of change of angle vs linear speed.
Soldato
It's where confusion can really come in. So days would be roughly 19 hours long? Or am i getting it the wrong way again?
Soldato
Same here.
It seems a LOT of effort, even once they get airborne. It is as though they are not really made to fly.
Soldato
I do get to use it. While quoting my smiley and offer of hugs you became abusive, you swore at me, you called me names. Repeatedly. I'm a big hippy with a thick skin and extremely high threshold of patience - but no - I do get to refuse to have any conversation with you, under circumstances if I chose to do so. All the evidence you would ever need is in post #67. Which, as you said, you won't read, because *cue bullying* plus some bizarre claims of three planets in one and 250% increases in gravity. So be it. I'm sorry, but I'm not going to re-word existing walls of text for you. I expected that abuse from you right there in post #67, where I said you can pick "the fight with the authors directly if you want - cause that's exactly what's coming" and that's exactly what came from you a single post later. As for the rest - read it, don't read it, why would I care, your siblings grandchildren will be taught about expansion tectonics in school, that much is certain.
Not sure where I confused it, but I'm so, so happy for any help with what's happening here. Especially as I've got bills and taxes to do today.
@Rilot, would you like to take over, please?
Don
OK, for earth: f = 6.67x10^-11 x (100kg X 5.9x10^24kg)/6378000M^2 = 967.4N
A planet half the radius and half the mass would be:
f = 6.67x10^-11 x (100kg X 2.95x10^24kg)/3189000M^2 = 1,934.8N so yes, double the surface gravity.
This is because the density of the body would be 4 times that of the earth
Volume of a sphere = 4/3 x pi x r^3
Volume of earth = 1.09x10^21 M^3
Volume of a planet of half the radius = 1.36x10^20 M^3
Earth has an average density of 5,412.8 kgM^-3
A planet of half the radius and half the mass has a density of 21,691.2 kgM^-3
A planet half the radius and half the mass would be:
f = 6.67x10^-11 x (100kg X 2.95x10^24kg)/3189000M^2 = 1,934.8N so yes, double the surface gravity.
This is because the density of the body would be 4 times that of the earth
Volume of a sphere = 4/3 x pi x r^3
Volume of earth = 1.09x10^21 M^3
Volume of a planet of half the radius = 1.36x10^20 M^3
Earth has an average density of 5,412.8 kgM^-3
A planet of half the radius and half the mass has a density of 21,691.2 kgM^-3
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Caporegime
Hi, geology graduate here.
Lol why are you guys such argumentative idiots sometimes?
Lol why are you guys such argumentative idiots sometimes?
I don't think the dinosaurs had the ability to develop test models..... can you imagine a T-rex trying to use a keyboard?
Soldato
QWERTY or QAOP?
Soldato
Now that is a fun "conspiracy" theory. There'd potentially be very little, if any, evidence left if there had been a dinosaur civilization. 66 million years would erase almost anything.
Either!
Soldato
Why did we arrive at higher density for our own planet again?
Should we do the theoretical constraints again? It's year 1gazillion and one B.C. Our earth, this very Earth, the Earth where the future primates will dance around black obelisk from Space Oddyseey 2001 and later on will be saved from asteroid impact by Bruce Willis and Ben Affleck. And Tommy Lee Jones will be left by Clint Eastwood on the surface of the moon.
The Earth of future You and I on OCUK - is a mostly lifeless rock with a form of atmosphere but the planet is smaller and lighter - half the mass and volume (jeez, I never doubted my command of English as much as I do today). The rock travels around the sun just as it is today and rotates just the same. Is the gravity on the surface of that Earth higher or lower?
(Everyone shouts "higher!" and I just stand up, slam the virtual door of GD, and scream into dark heavens where the smaller and lighter Venus is ironically blinking in my direction)
Soldato
Why did we arrive at higher density for our own planet again?
Should we do the theoretical constraints again? It's year 1gazillion and one B.C. Our earth, this very Earth, the Earth where the future primates will dance around black obelisk from Space Oddyseey 2001 and later on will be saved from asteroid impact by Bruce Willis and Ben Affleck. And Tommy Lee Jones will be left by Clint Eastwood on the surface of the moon.
Is the gravity on the surface of that Earth higher or lower?
(Everyone shouts "higher!" and I just stand up, slam the virtual door of GD, and scream into dark heavens where the smaller and lighter Venus is ironically blinking in my direction)
We arrived at that because you said half the size, which I took to mean half the radius. You seemed happy to go along with that, until it didn't work so well for you. Expanding earth theory seems to suggest about 55-60% of today's radius (not volume), so it made more sense to me that was what you were referring to.
Half the volume is different, half the volume and half the mass, lower gravity, about 80% of today's I think. So we need to lose more volume and mass to get to the "right" levels still.
Soldato
... (mumbles under moustache) ... "until it didn't work so well for you".... right. Because this has to... somehow... "work well for me"? Because this isn't me trying to explain a long standing scientific theory to you to the best of my English language skill and ability using simplified concepts, but somehow turned into me defending this theory as if it were some sort of pulled out of thin air hypothesis of my own, therefore this discussion has to "work well for me" for it to get.. what... validated? By you guys? (looks around) Is that what is happening here? This is a roast?
Tell you what. Why don't we just stop here - with it apparently completely "not working out so well for me".
This way I won't have to type walls of text that Angilion can dismiss based on pretend outrage, we (you and me) won't have to re-approach the same "more gravity if the planet is smaller" thing from multiple angles trying to trip up (what I really though were) very simple concepts by cunning linguistics "I said the same Earth half the mass and half the size - so I calculated radius - I said size - well, you didn't say 'no' to me calculating radius - I said size - ha, but not specifically 'volume' etc" for another 8 to 10 days. I'm not saying I didn't enjoy it - but it's somehow less fun after being sworn at and TBH, it feels like I'm being cornered in loops and circles as if there were extra points to be won for semantics. I'm not good at that, I won't be able to explain any of it any better than I already did.
The theory of Expansion Tectonics exists in one form or another since about 1888 (IIRC) and although I'm not quite sure if the professors and doctors working on it at this particular point in time seek validation from specialists in our particular fields, but if they do - you can tell them that I - namely - v0n - (head falls on chest) am entirely responsible for the failure of their great idea among my favourite forumites in these parts (immortalised as rising my finger with mouth half open like in that Nathan Fillon gif meme, as the crowd run circles around me pretending that Earth's Moon was heavy). When they come to mourn me, let them know that I fought bravely but it "did not work so well for me"? Mmmkay?
Unseul, it's been fun, the answer is still "~22mm per every completed orbit around the sun", it will bother you enough to one day lazily read though it yourself, and it totally works. Thanks for your brief help Rilot. Angilion, you're ugly, ugly man inside, but thanks for providing a quote for my new signature. And all of you GD be gone from my computer for at least a week as you cost me too much time.
Two final points:
1) I used briefer and coarser language than you did, but I was no more insulting than your post that I was replying to. I could have gone full Hansard and called you "my honourable colleague" first, but it wouldn't have changed the meaning. Only the delivery.
2) You didn't refuse to have any conversation with me. You refused to have any conversation with Unseul, using me as an excuse. That's what I was referring to and it seems I was right when I said it wouldn't fly.
It was an error to reply in anger. I should have just ignored you, which is what I am going to do now.
It was also an error to dismiss the message due to its delivery. Perhaps there is some mechanism by which a planet can significantly increase in size and quadruple in mass over a few dozen million years while remaining inhabitable throughout. I will feed some keywords to a search engine and look for a less condescending source. That won't be hard to find.
A big keyboard mounted on some sort of harness to put it within reach of their forelimbs. With configurable RGB lighting on the harness, of course
I happened to watch a snippet of video in a similar vein a few days ago. Not with dinosaurs, but with the homo genus. It was explicitly framed as wild speculation rather than any kind of theory because there's no evidence for it, but even over that much shorter period of time evidence could be extremely scarce or no longer exist at all. If some simple, low tech and localised homo erectus civilisations existed a million years ago, what would be left now? With 66 million years from the last of the terrestial dinosaurs then, as you say, almost anything would be erased. If there was an extinction level event that wiped out humanity in a short period of time from now and 66 million years in the future another species evolved to the same level of intelligence as humans, spread over the Earth and built their technology and infrastructure to the same level we have now...what would be left of us that they could find? Some evidence of widespread fossil fuel burning found in deep ice cores, maybe?
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I have a followup question:
What, if anything, could cause an Earthlike planet to experience such a large increase in rotational speed over a few dozen million years that the perceived gravity at its surface increased by 250% and to do so in a way that would not render it uninhabitable? I'm thinking that any situation that could accelerate the rotation of an Earthlike planet that much over that (relatively) short period of time would have catastrophic effects on it.
Soldato
A big keyboard mounted on some sort of harness to put it within reach of their forelimbs. With configurable RGB lighting on the harness, of course
I happened to watch a snippet of video in a similar vein a few days ago. Not with dinosaurs, but with the homo genus. It was explicitly framed as wild speculation rather than any kind of theory because there's no evidence for it, but even over that much shorter period of time evidence could be extremely scarce or no longer exist at all. If some simple, low tech and localised homo erectus civilisations existed a million years ago, what would be left now? With 66 million years from the last of the terrestial dinosaurs then, as you say, almost anything would be erased. If there was an extinction level event that wiped out humanity in a short period of time from now and 66 million years in the future another species evolved to the same level of intelligence as humans, spread over the Earth and built their technology and infrastructure to the same level we have now...what would be left of us that they could find? Some evidence of widespread fossil fuel burning found in deep ice cores, maybe?
The layer of evidence from fossil fuels makes me think I've seen the same video. Though I was first introduced to the idea (genuine possibility, as opposed to just cartoons/shows showing dinosaur people
) by the science of the discworld series. That sort of time would wipe out an enormous amount. I also wonder how significant usage of fossil fuels would need to be to leave evidence noticeable enough.Ice cores aren't any use, the oldest we have is 800,000 years. Very useful for what they cover, but it's such a tiny amount. I believe it's isotopes in dust/rock layers that can be measured, but I'd suppose you'd not only need enough fossil fuel use to show, but also, you need to analyse an extremely narrow band I'd presume.
