My young son is captivated by your q and a videos. You are having quite the impact over here in Fort Lauderdale. I can’t get him to go to sleep you’ve got him so energized. Great work! You are making a difference on young minds of the world! Means a lot to us!
Another reason they refer to things like the ISS being in microgravity is that every bit of it is trying to follow a slightly different orbit. The left side is trying to move to the right, the right to the left, the higher bits want to go a bit slower, the lower bits a bit faster... If they weren't all bolted together, the parts would slowly all move away from each other. Except for a line down the middle, every piece of it has a slightly different gravitational force acting on it.
I take issue with your explanation of microgravity vs zero gravity. The term microgravity, as opposed to zero gravity, emphasizes that even on the ISS, experiments experience low accelerations measured in millionths of a g. The term is not used to emphasize that objects in orbit are still under the influence of the earth's gravity, and to say that it is creates confusion: it makes it sound like earth's gravity at that altitude is down to micro-gs, when it's actually, as you said, about 0.9g. Within their own frame of reference, astronauts in orbit experience zero acceleration, not zero gravity. I prefer the term zero-g (because they experience 0g of acceleration, where g=9.8ms^-2)
Hi Frazer. I ve got a theoretical question. Lets say that a spaceship elliptically approaches a super massive black hole and her orbit passes just inside of the horizon. When she is in there (I guess she won't make it out due to space time abnormalities :) ) she fires her super advanced ion engines to get out. What will stop her exit the black hole horizon?
I've read that someone did calculations for the surface gravity of planets with a similar composition as Earth, Venus, and Mars, which concluded that even when you increase the amount of rocky material, the gravity at the surface does not go significantly higher than on Earth. The increased gravity and the distance from the center start to almost cancel each other out for a planet only slightly larger than Earth. I think 1.1 or 1.2 Earth gravity would probably be quite survivable over long amounts of time, but regular exercise and physiotherapy for the elderly would likely be a much more important part of healthcare. You could of course have planets with different compositions and a higher ratio of heavier elements as in Mercury, which still would result in significantly higher surface gravities.
Beware of the revenge of the 5th! :-) Apparently also astronaut day in the US since it's the anniversary of Alan Shepard's flight. First ticket on New Shepard goes on auction and the flight is on July 20th.
Question: would a spacecraft going through a nebula loose a significant amount of speed like it was some sort of "air resistance" ? Or are the particles not close enough to make a difference?
But there are space twisters, for instance, in the Lagoon nebula. And stars are born in nebulae. So there is some concentration of matter in those regions, and, in the images provided by Hubble, nebulas seem rather homogeneous in terms of density, and... maybe also temperature. How dense and hot are they?
Question here. Aren't we allowing our technological perseverance to be left behind by abandoning SSTO technology (like the X-33) and relying on reusable multi-stage rockets to travel into orbit? For me it is completely more practical to servicing a single stage than 2 stages like the starship. And is there any chance that another company will "buy" Lockheed Martin's X-33 technology and put it to use for something more substantial than an abandoned project? Maybe a orbital liner?
Wait, isn't there some kind of Plank gravity? Like I mean there is the Plank constant thing that nothing can get smaller than that constant, and there is the reverse square law that describes falloff of any radiation the gravity is a sort off. So the further objects are from each other the lower gravity influence is. And given enough distance, the influence might become as little as plank gravity and after that point became exactly zero? Well it might be far beyond observable universe, but that depends on the initial mass. Like if there is only two atoms in the whole universe...
Internet: "...Planck length is approximately the size of a black hole where quantum and gravitational effects are at the same scale: where its Compton wavelength and Schwarzschild radius are the same..."
@@doncarlodivargas5497 Yes but, as gravity is essentially acceleration, I mean plank acceleration. And I assume after that it might became zero given more distance.
Hey Fraser! I love your brain and want to pick at it -- If black holes suck everything in and white holes spit everything out into the universe; wouldn't it make sense that we would see things out there (white holes) constantly blasting stuff out of it? Or is everything so far away for us to even see it? As in it's beyond our observable universe? Thanks
Question. So now that SN15 has flown and done all its stuff and landed safely do you know if they will use it again for anything or will it just get parked by the Hopper and they will move on to SN16?
“Eventually gravity will reach every destination”. Not the gravity from over the horizon of visible Universe, right? Even less. Due to the expansion of the Universe. So in a way we have a gravity cut-off every single second as more go over the horizon? 😳🤔 Does it get “lighter” and “lighter”?
Question: Whould free falling be micro gravity or zero gravity? I thought when you are free falling somewhere in space, everything affects you gravitationally, but just in a way that changes your geodesic. On such a geodesic, you would not be accelerated, or feel any g forces at all. So wouldn't that be zero gravity? (assuming earth gravity means that we feel 1g)
Hey Fraser, how do you think space exploration will evolve in 1000 years? Will we colonize sollar system or even reach closest stars? I mean it's not that much on scale of our civilization. What we should aim for this time scale? Thanks!
In 1,000 years, sure, we'll be going to other stars. If you just continue our current technological growth, we'll probably set off to other stars in a few hundred years.
According to my calculations just going from the temperature of the clouds (-145c) to room temperature will cause gasses to expand by two and a third times. Given a sufficient heat source and a reeallly big balloon it should be possible.
if the starship was the cheapest lander option, would it maybe also be cheaper than the gateway, too? maybe replace the sea level engines with ion engines and even add some sort of crew access port to the fuel tank bulkheads to use that as habitable area as well.
Awesome QnAs!! my question: can we realistically build a powerful enough telescope to see a nearby earth like exoplanet and resolve its surface features like mountains, continents,oceans etc, is it possible ??
What does microgravity feel like? Free falling? If so, is it constant? Or does the body get used to it. I hate free falling I wouldn't like to spend much time doing it.
Fraser, I have a question that I don't know if you have answered before, do they have some sort of scale like device that can be used in micro gravity environments? How do they measure mass of regular things or humans in the ISS?
Interesting question. I imagine a lot of the experiments require exact measurements for ingredients and results. I wonder if most such measurements are based on volume instead of mass. Or they could measure the inertial mass (m = F/a), but i don't think that's very practical. On the other hand, i don't think they measure humans by volume 😉
@@PaulPaulPaulson Inertial mass is EXACTLY what must be measured in a microgravity environment. Volume can determine an object's mass if its density is precisely known.
Hi Fraser, I was looking at the Martian rover as you mentioned the dust accumulation on its solar cells. Would it be possible to have the equivalent of a car's windshield wiper to keep that dust off?
We know that the atmosphere of Mars is too thin to support liquid water at ground level. How deep would we need to get to have enough atmospheric pressure to have any liquid water (that is fresh water that is not very salty.)? Would it even be possible at some deep craters or basins?
Try forget the heat, and focus on gravity alone for a sec - what is the Sun's 'event horizon' currently? As in, based on technology we are capable of today, how close could you get to it and still be able to escape?
Hold on! At a certain distance, (a very big distance), the spacetime "gradient" angle between the two bodies will be a Planck length or some other length un-distinguishable from wobbly quantum tininess and thus effectively 'flat' - so no gravity between the two bodies. No?
If there were only two stars in the universe separated by the distance cosmologists believe the universe has expanded to since the big bang (about 93 billion light years), the effects of their respective masses on one another via the curvature of space-time, all things being equal, would cause them to move towards one another. However, since the universe is expanding, a second order equation must be used to understand if the space-time curvature between the two starts is decreasing (as the universe expands) at a rate that suggests the starts would reach infinity (or not) before they stop and start falling back towards one another.
Mars 1 was based on the idea of broadcasting the program, but, as far as I know, there is no way to do that. I wonder how expensive it would be to place a sun-powered laser on Mars, and have a broadband connection to Earth. Maybe there is a market for that.
The question about is the universe open or closed. Will it eventually contract or will it expand forever. I know this doesn't seem to be the case but what if the Universe was rotating about itself. That could create a balance where it neither contracted or expanded. Just like in our solar system. You would have a universe that wouldn't suffer from the cold death. But if it was rotating the rotation speed must be such that it is greater than the force of gravity holding it because of expansion that has been measured. In other words that centrifical force would be greater than the gravity force. They have found dark energy though that they say is responsible for the expansion but I wonder have they really found that energy and measured it.
As the falling elevator approaches terminal speed (due to air drag), you will be approaching normal 1G. Just a note of what you would experience. Skydivers don't "freefall" like astronauts do in orbit. If you jump from a hot air balloon, you get that fall for only a few seconds before you are in 1G (feeling).
Is it possible to build a landing pad on the moon by melting the regolith? I imagine a rover with a parabolic mirror that uses sunlight to melt a small spot, let it cool and move a bit over. After some time the rover will have created a hardened area big enough to land a spacecraft without blasting rocks all over the place.
Instead of de-orbiting the ISS can/should they boost it up into a much higher orbit, then depressurize it and save it for posterity? Seems a shame to just throw it away.
Re: biggest exoplanet we can live on. From theoretical models of planetary structure, there is a power relationship between the mass and the radius of a rocky planet with an iron core. R/R⊕ = (M/M⊕)⁰·²⁶⁹⁵ The average density of a rocky exoplanet is slightly variable with the planet's total mass: ρ = 5.513 g/cm⁻³ (M/M⊕)⁰·¹⁹¹⁵ The surface gravity of a rocky exoplanet is therefore g = 9.806 m sec⁻² (M/M⊕)⁰·⁴⁶¹⁰ Choose a value for the exoplanet's surface gravity, g, in meters per second squared. M/M⊕ = 10^{ log (g/9.806) / 0.461 } R/R⊕ = (M/M⊕)^0.2695 If people can live longterm under a maximum gravity field of 15 m sec⁻², then the biggest habitable exoplanet is M = 2.5144 M⊕ R = 1.2821 R⊕
@@frasercain I should say that the above equations assume that the core is assumed to be all iron and comprises 32% of the exoplanet's mass. The density at the center of the planet is estimated from a model of cold iron under pressure, then fiddled with until the pressure comes out to be (almost) zero after stacking the planet in concentric spherical shells of 10 cm thickness from the inside out. (If the pressure doesn't work out to zero at the surface, when you've added all the mass, then the estimate for the core density or core pressure, or both, was wrong, so revise and start over.) I wrote a rocky planet structure program in Python 3.4, which starts with the iron core until all the required core mass is completely added, then transitions to a mantle (assumed to be magnesium silicate, if I remember correctly) until the rest of the exoplanet's mass has been added. There's a final bit for oceans, if I want to turn it on.
@@frasercain Natural selection would weed out the weak people who couldn't adjust to 1.5 g's, leaving the STRONG to inherit the exoplanet. That's how nature makes its best stuff.
Sure people could survive 15 m/s^2 but they’ll never leave. Earth is already pretty close to the maximum sized planet that chemical rockets can still get into orbit. A super-Earth would require a Saturn V to launch a single cube sat. Future humanity would be well served by avoiding big gravity wells.
If antimatter turns out to fall up instead of down, would that explain why there seems to be more matter than antimatter in the universe - as it all just falls away and doesnt condense to make up planets and galaxies and stuff? Maybe its all there, in the inter galactic void and could even have something to do with dark energy?
Sort of. The Universe is also expanding, so it's a little more than that. But every minute that goes by, you're seeing a new, bigger part of the Universe.
The question on Gravity is interesting but unresolved at the moment. If spacetime is not infinitesimally smooth, i.e. if there is a minimal length where nothing can be shorter in spacetime (that is, if the Planck limit is real) then gravity would NOT be infinite. At some distance, the warping of local spacetime will reach that limit and therefore local spacetime will not be warped at all by the effect of matter at that distance or further. On the other hand, Einstein's theories REQUIRE spacetime to be infinitely smooth for the math to work, hence what seems to be the unresolved conflict between an as yet undetermined theory of quantum gravity and Einstein's theories concerning gravity. In other words, if gravity is not quantized, then you are right. If gravity is quantized, then gravity is not infinite.
Mr Fraser Cain your answer to the first question is wrong, remember the universe is expanding, this creates a cosmic horizon. Correction, I missed that the person who ask the question stated that there was no expansion, my mistake. But the comments on my comment are to interesting so i will not delete my comment. My apology Mr Cain.
@@jimkoss3318 Regardless of what actually causes cosmic redshift, the edge of the observable Universe is where the redshift is so great that the wavelengths of the redshifted photons cannot be contained in the observable Universe. In my opinion as a profesional Physicist, a photon with wavelength longer that the circumference of the observable Universe cannot exist. I think that the entire Universe resonates as a spherical quantum wave with this maximum possible wavelength.
Is that statement about gravity supported by evidence or just theory. What if gravity is quantized and there's a smallest amount of it, after which there is no effect. Isn't that a (strong) possibility?
For the last six months almost all of your youtube content has been either Q&A's or interviews. Will there be any more "regular" videos where you talk about just one subject in depth?
@@frasercain maybe you could create shorter topic specific videos by editing together parts of one or more interviews and adding just a small amount of new video to connect the pieces together.
@@frasercain That sounds good. I figured that the lack of normal scripted videos makes the channel harder to find and approach for new viewers, as most people are used to that kind of a format and are probably more unlikely to click on a video with "interview" or especially "Q&A" in the title from a channel they have not watched before. Doing good work.
@@frasercain Ingenuity’s rotors would be above Perseverance’s panels during flight. I’m talking about cleaning Perseverance’s panels. I liked your idea of spinning Ingenuity to clean its own panels.
With the amount of rubbish in orbit threatening to limit us to the Earth, is allowing anybody to launch stuff into orbit (due to falling costs to launch) such a good idea?
Is Sirius A a gas thief? Seems a little young for a white dwarf to be orbiting it. However, the star would appear young if it stole its partners gas when that partner was a red giant. Am I off base for thinking this?
That would be cool with the whole like mystical concept of like a universal consciousness was somehow proven true one day and it's tied to gravity like that would like kind of explain how you know everything everywhere in the universe is like connected somehow cuz like gravity is connected to all other things like your kind of makes sense conspiracy theory sort of way
I have been following you for about 2 years now. And I really enjoy your q&a. But I have to admit that about six maybe eight months ago when you were talking about climate change, it got me upset because I felt you were talking out of your element. I didn't unsubscribe from your channel, but I stopped viewing your videos. This is the first video that I saw produced by you in a long long time. I realize how much I enjoy learning from you. You do such a great job with your videos and I love how you added these skip to the question on your videos. I guess what I'm trying to say, is that although you and I have a few disagreements, I respect your skills, your talent and the enormous amount of effort you put into your videos. Thank you for what you do.
It is so frustrating to see the painfully obvious solution to power on Mars is being universally ignored: microwave power beaming from solar power sats. Low mass/area mirrors can compensate for the lower intensity of sunlight at Mars and dust storms have no effect on microwave beams. A constellation of solar power sats in low to medium Mars orbit can provide constant power, comm and positioning to anywhere on the planet. The sats can use their power to get themselves from LEO to LMO with cargo using electric propulsion.
This is likely the single biggest reason for colonizing Mars from orbit first. Phobos and Deimos are convenient hardware stores out of which we should be able to manufacture a decent sized Stanford Torus or O’neill Cylinder. It should be comparatively easy to build an orbital solar farm. The biggest argument for Moon-first is the proximity to Earth and help. A large population in/on/near Phobos would be Mars’ base of safety. Rescuing Watney/Damon from the surface of Mars would be almost trivially easy.
@@frasercain Compared to surface based solar? Nuclear with its astronomical cost? Keep in mind that these sats transport not just themselves with less required propellant vs. chemical, but also cargo. Solar electric propulsion has been itself proposed as viable just for cargo transport. Using that electrical power to beam microwaves to the surface from Mats orbit involves no great tech leap and was considered viable in the 1960's. I must admit I am both baffled and disappointed by your objection that it is not "simple" enough. Is Starlink too complicated? Power, comm and positioning to any point on the planet at any time immune to single point failure vs. systems that have to be landed on the surface at significant propellant cost and serve only a limited area seems like a no brainer to me. Mars can be a power rich environment eventually able to facilitate beamed power propulsion for faster and more frequent travel to and from Mars..
What about poo, every astronaut is doing it? What’s radiation shielding abilities of poo? Or for that matter it’s r-value and it’s benefits in slowing down micro meteorites. Just feel there’s got to be a better use than Martian potatoes
No for two reasons: 1) Too many of those rovers' electrical components are dead by now. 2) There are thousands of kilometers away from ingenuity. They're on different continents if you will.
"The outward expanding force of dark energy is accelerating the galaxies even faster apart." Isn't that just a fancy pseudo-scientific way of saying that we have no idea why the expansion of the observable universe is speeding up? We can't detect dark energy, or dark matter, and we don't know how anything can even interact with them. But we see something unexplainable happening, so we postulate the existence of some magical stuff. Occam's Razor be damned! Whatever!
You may not know it, but there is much more to the story than that. Maybe you should try reading through some actual published paper about dark matter instead of relying solely on what you've heard on youtube.
Fraser why are you making only question shows? I normal skip those because well not my style to use as podcast video. I was searching for your last "normal or well topic video" thats 7 months ago? Are you going to stop those or really need to watch all q&a video`s for that answer? Well you probably dont give shit about a user. -i love your topic video`s. Iam more a direct answer man. So short yes no its ok by me.
I'm also doing long and fascinating interviews. The main reason is that I felt the quality of my scripted work wasn't good enough and I wanted to get closer to the sources. So I've been bringing in the actual scientists who are doing this work and taking the conversation to the next level. The long-term plan is to take this deeper understanding and re-integrate it with my own perspective to tie themes together, but this is where my interests are right now. If that's not your interest, no problem. Thanks for watching!
I know that you, like others, are captivated by the idea that the speed of light is the basis of the universe, you and others are wrong. I regret to tell you that the highest speed in the universe is now: 9 x 10 power 12 km / s, Greetings
I hope you never stop doing these Q&A's!!
My young son is captivated by your q and a videos. You are having quite the impact over here in Fort Lauderdale. I can’t get him to go to sleep you’ve got him so energized. Great work! You are making a difference on young minds of the world! Means a lot to us!
Oh great, say hi! 😄
Another reason they refer to things like the ISS being in microgravity is that every bit of it is trying to follow a slightly different orbit. The left side is trying to move to the right, the right to the left, the higher bits want to go a bit slower, the lower bits a bit faster... If they weren't all bolted together, the parts would slowly all move away from each other. Except for a line down the middle, every piece of it has a slightly different gravitational force acting on it.
I take issue with your explanation of microgravity vs zero gravity. The term microgravity, as opposed to zero gravity, emphasizes that even on the ISS, experiments experience low accelerations measured in millionths of a g. The term is not used to emphasize that objects in orbit are still under the influence of the earth's gravity, and to say that it is creates confusion: it makes it sound like earth's gravity at that altitude is down to micro-gs, when it's actually, as you said, about 0.9g.
Within their own frame of reference, astronauts in orbit experience zero acceleration, not zero gravity. I prefer the term zero-g (because they experience 0g of acceleration, where g=9.8ms^-2)
I like that these video uploads don't contain interjections from and to a live audience and long pauses with nothing, unlike most recycled streams.
It's a 90 minute livestream cut down. :-)
About Mars and dust. I don't understand, wouldn't all the dust problems be solved by attaching a wiper blade to rover's solar panels?
Hi Frazer. I ve got a theoretical question. Lets say that a spaceship elliptically approaches a super massive black hole and her orbit passes just inside of the horizon. When she is in there (I guess she won't make it out due to space time abnormalities :) ) she fires her super advanced ion engines to get out. What will stop her exit the black hole horizon?
These videos are awesome ! Look forward to them every week
I've read that someone did calculations for the surface gravity of planets with a similar composition as Earth, Venus, and Mars, which concluded that even when you increase the amount of rocky material, the gravity at the surface does not go significantly higher than on Earth. The increased gravity and the distance from the center start to almost cancel each other out for a planet only slightly larger than Earth. I think 1.1 or 1.2 Earth gravity would probably be quite survivable over long amounts of time, but regular exercise and physiotherapy for the elderly would likely be a much more important part of healthcare.
You could of course have planets with different compositions and a higher ratio of heavier elements as in Mercury, which still would result in significantly higher surface gravities.
Beware of the revenge of the 5th! :-)
Apparently also astronaut day in the US since it's the anniversary of Alan Shepard's flight. First ticket on New Shepard goes on auction and the flight is on July 20th.
Great questions and answers!
Question: would a spacecraft going through a nebula loose a significant amount of speed like it was some sort of "air resistance" ? Or are the particles not close enough to make a difference?
No, it's almost empty, no friction
@@frasercain thanks for the quick answer! It just popped in my brain and I just needed to know 😂😂
But there are space twisters, for instance, in the Lagoon nebula. And stars are born in nebulae. So there is some concentration of matter in those regions, and, in the images provided by Hubble, nebulas seem rather homogeneous in terms of density, and... maybe also temperature. How dense and hot are they?
Question here.
Aren't we allowing our technological perseverance to be left behind by abandoning SSTO technology (like the X-33) and relying on reusable multi-stage rockets to travel into orbit? For me it is completely more practical to servicing a single stage than 2 stages like the starship. And is there any chance that another company will "buy" Lockheed Martin's X-33 technology and put it to use for something more substantial than an abandoned project? Maybe a orbital liner?
Always love these videos!
Wait, isn't there some kind of Plank gravity? Like I mean there is the Plank constant thing that nothing can get smaller than that constant, and there is the reverse square law that describes falloff of any radiation the gravity is a sort off. So the further objects are from each other the lower gravity influence is. And given enough distance, the influence might become as little as plank gravity and after that point became exactly zero? Well it might be far beyond observable universe, but that depends on the initial mass. Like if there is only two atoms in the whole universe...
Internet: "...Planck length is approximately the size of a black hole where quantum and gravitational effects are at the same scale: where its Compton wavelength and Schwarzschild radius are the same..."
@@doncarlodivargas5497 Yes but, as gravity is essentially acceleration, I mean plank acceleration. And I assume after that it might became zero given more distance.
7:48 - Polite martians with feather dusters.
How soon do you think we'll have a colony on the moon and/or mars?
How soon do you think that colony could become self-sustaining?
Hey Fraser! I love your brain and want to pick at it -- If black holes suck everything in and white holes spit everything out into the universe; wouldn't it make sense that we would see things out there (white holes) constantly blasting stuff out of it? Or is everything so far away for us to even see it? As in it's beyond our observable universe? Thanks
Q&A. Is it possible for NASA or any other space program to land a rover or a lander on Mars’ Olympus Mons?
Sure, but the atmosphere is thinner at that high atmosphere, so it's tougher.
Question. So now that SN15 has flown and done all its stuff and landed safely do you know if they will use it again for anything or will it just get parked by the Hopper and they will move on to SN16?
Musk said they "might" refly SN15, so we'll have to keep watching to see what happens.
“Eventually gravity will reach every destination”. Not the gravity from over the horizon of visible Universe, right? Even less. Due to the expansion of the Universe.
So in a way we have a gravity cut-off every single second as more go over the horizon? 😳🤔 Does it get “lighter” and “lighter”?
Question: Whould free falling be micro gravity or zero gravity? I thought when you are free falling somewhere in space, everything affects you gravitationally, but just in a way that changes your geodesic. On such a geodesic, you would not be accelerated, or feel any g forces at all. So wouldn't that be zero gravity? (assuming earth gravity means that we feel 1g)
What is the news on the ISS replacements, Lunar Orbital Platform and Voyager Station? Also what about repurposing the ISS to be a Lunar orbiter?
Hey Fraser, how do you think space exploration will evolve in 1000 years? Will we colonize sollar system or even reach closest stars? I mean it's not that much on scale of our civilization. What we should aim for this time scale? Thanks!
In 1,000 years, sure, we'll be going to other stars. If you just continue our current technological growth, we'll probably set off to other stars in a few hundred years.
@@frasercain sounds very exciting and not that far away for human time scale
32:50 if you have a fusion reactor just make the hydrogen hot. Hot hydrogen balloon. 😉
According to my calculations just going from the temperature of the clouds (-145c) to room temperature will cause gasses to expand by two and a third times. Given a sufficient heat source and a reeallly big balloon it should be possible.
if the starship was the cheapest lander option, would it maybe also be cheaper than the gateway, too? maybe replace the sea level engines with ion engines and even add some sort of crew access port to the fuel tank bulkheads to use that as habitable area as well.
Hi Fraser, so why is space so cold, what is it that makes space such an extremely cold place?
You need molecules heated up to have a temperature at all. There are very few molecules in space.
Is gravity caused by time dilation due to mass?
Can be viewed that way. There are a number of videos on this. Check out the one from PBS Spacetine.
Awesome QnAs!! my question: can we realistically build a powerful enough telescope to see a nearby earth like exoplanet and resolve its surface features like mountains, continents,oceans etc, is it possible ??
Calculate the resolving power of a telescope to determine how large such a telescope would need to be.
What does microgravity feel like? Free falling? If so, is it constant? Or does the body get used to it. I hate free falling I wouldn't like to spend much time doing it.
Yes, it would feel like free falling, astronauts do get used to it, but many vomit.
Due to varying gravity from planet to planet, will geology and rock classification be different on other planets?
If an earthlike exoplanet had extreme weather, Would Storm Chasing be fun?
Fraser, I have a question that I don't know if you have answered before, do they have some sort of scale like device that can be used in micro gravity environments? How do they measure mass of regular things or humans in the ISS?
Interesting question. I imagine a lot of the experiments require exact measurements for ingredients and results. I wonder if most such measurements are based on volume instead of mass. Or they could measure the inertial mass (m = F/a), but i don't think that's very practical. On the other hand, i don't think they measure humans by volume 😉
Mass is measured as the ability of an object to resist being accelerated by a given force. That's a restatement of Newton's 2nd Law.
@@PaulPaulPaulson Inertial mass is EXACTLY what must be measured in a microgravity environment. Volume can determine an object's mass if its density is precisely known.
Hi Fraser,
I was looking at the Martian rover as you mentioned the dust accumulation on its solar cells. Would it be possible to have the equivalent of a car's windshield wiper to keep that dust off?
The problem is that it's electrostatically charged, so you might just be scraping it back and forth causing damage.
Frack yes, Fraser!!!! 🤘🤘🤘
We know that the atmosphere of Mars is too thin to support liquid water at ground level. How deep would we need to get to have enough atmospheric pressure to have any liquid water (that is fresh water that is not very salty.)? Would it even be possible at some deep craters or basins?
Try forget the heat, and focus on gravity alone for a sec - what is the Sun's 'event horizon' currently? As in, based on technology we are capable of today, how close could you get to it and still be able to escape?
Is there a sound on moon? Would you be able to hear the astroid impact 1 kilometer away?
Your work is fantastic!
Hold on! At a certain distance, (a very big distance), the spacetime "gradient" angle between the two bodies will be a Planck length or some other length un-distinguishable from wobbly quantum tininess and thus effectively 'flat' - so no gravity between the two bodies. No?
If there were only two stars in the universe separated by the distance cosmologists believe the universe has expanded to since the big bang (about 93 billion light years), the effects of their respective masses on one another via the curvature of space-time, all things being equal, would cause them to move towards one another. However, since the universe is expanding, a second order equation must be used to understand if the space-time curvature between the two starts is decreasing (as the universe expands) at a rate that suggests the starts would reach infinity (or not) before they stop and start falling back towards one another.
Mars 1 was based on the idea of broadcasting the program, but, as far as I know, there is no way to do that. I wonder how expensive it would be to place a sun-powered laser on Mars, and have a broadband connection to Earth. Maybe there is a market for that.
The question about is the universe open or closed. Will it eventually contract or will it expand forever. I know this doesn't seem to be the case but what if the Universe was rotating about itself. That could create a balance where it neither contracted or expanded. Just like in our solar system. You would have a universe that wouldn't suffer from the cold death. But if it was rotating the rotation speed must be such that it is greater than the force of gravity holding it because of expansion that has been measured. In other words that centrifical force would be greater than the gravity force. They have found dark energy though that they say is responsible for the expansion but I wonder have they really found that energy and measured it.
As the falling elevator approaches terminal speed (due to air drag), you will be approaching normal 1G. Just a note of what you would experience. Skydivers don't "freefall" like astronauts do in orbit. If you jump from a hot air balloon, you get that fall for only a few seconds before you are in 1G (feeling).
When you're skydiving, you hit terminal velocity, so it feels like you're in gravity again. Freefalling never ends.
Gravity to me, seems like everything is falling, perpetually, away from one place.
Maybe as the heavier elements are made, it fuels this 'falling' ?
No, everything is falling, but in different directions depending on where the most mass is.
Is it possible to build a landing pad on the moon by melting the regolith? I imagine a rover with a parabolic mirror that uses sunlight to melt a small spot, let it cool and move a bit over. After some time the rover will have created a hardened area big enough to land a spacecraft without blasting rocks all over the place.
Instead of de-orbiting the ISS can/should they boost it up into a much higher orbit, then depressurize it and save it for posterity?
Seems a shame to just throw it away.
It's really really heavy, so that would take an enormous number of launches and propellant.
TY interesting
Re: biggest exoplanet we can live on. From theoretical models of planetary structure, there is a power relationship between the mass and the radius of a rocky planet with an iron core.
R/R⊕ = (M/M⊕)⁰·²⁶⁹⁵
The average density of a rocky exoplanet is slightly variable with the planet's total mass:
ρ = 5.513 g/cm⁻³ (M/M⊕)⁰·¹⁹¹⁵
The surface gravity of a rocky exoplanet is therefore
g = 9.806 m sec⁻² (M/M⊕)⁰·⁴⁶¹⁰
Choose a value for the exoplanet's surface gravity, g, in meters per second squared.
M/M⊕ = 10^{ log (g/9.806) / 0.461 }
R/R⊕ = (M/M⊕)^0.2695
If people can live longterm under a maximum gravity field of 15 m sec⁻², then the biggest habitable exoplanet is
M = 2.5144 M⊕
R = 1.2821 R⊕
I wonder what the max gravity we could handle. 15 m/s2 sounds like a lot
@@frasercain I should say that the above equations assume that the core is assumed to be all iron and comprises 32% of the exoplanet's mass. The density at the center of the planet is estimated from a model of cold iron under pressure, then fiddled with until the pressure comes out to be (almost) zero after stacking the planet in concentric spherical shells of 10 cm thickness from the inside out. (If the pressure doesn't work out to zero at the surface, when you've added all the mass, then the estimate for the core density or core pressure, or both, was wrong, so revise and start over.) I wrote a rocky planet structure program in Python 3.4, which starts with the iron core until all the required core mass is completely added, then transitions to a mantle (assumed to be magnesium silicate, if I remember correctly) until the rest of the exoplanet's mass has been added. There's a final bit for oceans, if I want to turn it on.
@@frasercain Natural selection would weed out the weak people who couldn't adjust to 1.5 g's, leaving the STRONG to inherit the exoplanet. That's how nature makes its best stuff.
Sure people could survive 15 m/s^2 but they’ll never leave. Earth is already pretty close to the maximum sized planet that chemical rockets can still get into orbit. A super-Earth would require a Saturn V to launch a single cube sat. Future humanity would be well served by avoiding big gravity wells.
If antimatter turns out to fall up instead of down, would that explain why there seems to be more matter than antimatter in the universe - as it all just falls away and doesnt condense to make up planets and galaxies and stuff? Maybe its all there, in the inter galactic void and could even have something to do with dark energy?
Is the observable universe increasing by 1-light minute in all directions, for every minute that passes?
Sort of. The Universe is also expanding, so it's a little more than that. But every minute that goes by, you're seeing a new, bigger part of the Universe.
The question on Gravity is interesting but unresolved at the moment. If spacetime is not infinitesimally smooth, i.e. if there is a minimal length where nothing can be shorter in spacetime (that is, if the Planck limit is real) then gravity would NOT be infinite. At some distance, the warping of local spacetime will reach that limit and therefore local spacetime will not be warped at all by the effect of matter at that distance or further. On the other hand, Einstein's theories REQUIRE spacetime to be infinitely smooth for the math to work, hence what seems to be the unresolved conflict between an as yet undetermined theory of quantum gravity and Einstein's theories concerning gravity. In other words, if gravity is not quantized, then you are right. If gravity is quantized, then gravity is not infinite.
Mr Fraser Cain your answer to the first question is wrong, remember the universe is expanding, this creates a cosmic horizon.
Correction, I missed that the person who ask the question stated that there was no expansion, my mistake. But the comments on my comment are to interesting so i will not delete my comment. My apology Mr Cain.
More specifically, the particle horizon at a radius of 4.4x10^26 meters limits the reach of gravity.
The question stated zero expansion.
@@jimkoss3318 Regardless of what actually causes cosmic redshift, the edge of the observable Universe is where the redshift is so great that the wavelengths of the redshifted photons cannot be contained in the observable Universe.
In my opinion as a profesional Physicist, a photon with wavelength longer that the circumference of the observable Universe cannot exist. I think that the entire Universe resonates as a spherical quantum wave with this maximum possible wavelength.
@@jimkoss3318 You are right, my mistake.
SN15 just landed successfully. Crack open a cold one!
So fantastic!
But if the universe is expanding, might the two stars all alone in the universe move apart from expansion faster than gravity pulls them together?
Yes, absolutely. This is assuming a static Universe
Even if true beyond a certain point gravity becomes a rounding error.
What is cleaning solar panels on Mars?
Aliens.
If we can't explain something immediately, it's definitely aliens.
But seriously, thanks for making these Fraser! I really like listening these in the background.
Whoa... aliens.
OMG! How much velocity would passing gas give you in space?
Do they do underground toot race gambling?
Hey Fraser, is the financial cost of going to Mars cheaper than rather building DS9? Nuclear powered.
Hi Fraser, is JWST going to answer the question, whether red dwarf stars are conducive to life in their habitable zone?
Ted dwarf stars frequently flare, which would be extremely hazardous to life in the habitable zone.
@@stevenverrall4527 Older more 'calm' red dwarves?
Is that statement about gravity supported by evidence or just theory. What if gravity is quantized and there's a smallest amount of it, after which there is no effect. Isn't that a (strong) possibility?
Bill Gaedean Rope theory
Solar panel cleaning events on Mars... It's aliens :)
For the last six months almost all of your youtube content has been either Q&A's or interviews. Will there be any more "regular" videos where you talk about just one subject in depth?
I'm not sure, I've mentioned that I'm unhappy with my level of detail on the the scripted videos, while the interviews go right to the source.
@@frasercain maybe you could create shorter topic specific videos by editing together parts of one or more interviews and adding just a small amount of new video to connect the pieces together.
That's the plan. The interviews are the foundation
@@frasercain That sounds good. I figured that the lack of normal scripted videos makes the channel harder to find and approach for new viewers, as most people are used to that kind of a format and are probably more unlikely to click on a video with "interview" or especially "Q&A" in the title from a channel they have not watched before. Doing good work.
Can a moon have a moon? Or is it called something different?
In theory, yes, but none have been observed in the Solar System.
Would sand fall off if they tipped the solar panels?
If matter is finite, then so is gravity.
He was talking about its reach, not its amount.
Use the helicopter to remove the dust on the rover
The panel is above the rotors.
@@frasercain Ingenuity’s rotors would be above Perseverance’s panels during flight. I’m talking about cleaning Perseverance’s panels.
I liked your idea of spinning Ingenuity to clean its own panels.
Perseverance doesn't have solar panels
With the amount of rubbish in orbit threatening to limit us to the Earth, is allowing anybody to launch stuff into orbit (due to falling costs to launch) such a good idea?
Space nookey. Come on now, it must happen. Anything to look forward to there?
👍👍👍
Floating around Jupiter would still be deadly because of the insane radiation from the planet.
No, you're inside the magnetosphere, like the Earth
not flown yet :(
Is Sirius A a gas thief? Seems a little young for a white dwarf to be orbiting it. However, the star would appear young if it stole its partners gas when that partner was a red giant. Am I off base for thinking this?
That would be cool with the whole like mystical concept of like a universal consciousness was somehow proven true one day and it's tied to gravity like that would like kind of explain how you know everything everywhere in the universe is like connected somehow cuz like gravity is connected to all other things like your kind of makes sense conspiracy theory sort of way
(when gravity is objects/particles shielding you from cosmic radiation/background radiation/dark matter gravity is never more than the speed of light)
Plot twist... what we observe as the big bang is actually just the outlet end of a black hole...
I have been following you for about 2 years now. And I really enjoy your q&a. But I have to admit that about six maybe eight months ago when you were talking about climate change, it got me upset because I felt you were talking out of your element. I didn't unsubscribe from your channel, but I stopped viewing your videos. This is the first video that I saw produced by you in a long long time. I realize how much I enjoy learning from you. You do such a great job with your videos and I love how you added these skip to the question on your videos. I guess what I'm trying to say, is that although you and I have a few disagreements, I respect your skills, your talent and the enormous amount of effort you put into your videos. Thank you for what you do.
It is so frustrating to see the painfully obvious solution to power on Mars is being universally ignored: microwave power beaming from solar power sats. Low mass/area mirrors can compensate for the lower intensity of sunlight at Mars and dust storms have no effect on microwave beams. A constellation of solar power sats in low to medium Mars orbit can provide constant power, comm and positioning to anywhere on the planet. The sats can use their power to get themselves from LEO to LMO with cargo using electric propulsion.
A constellation of solar beaming satellites doesn't sound like a simple solution. 😄
This is likely the single biggest reason for colonizing Mars from orbit first. Phobos and Deimos are convenient hardware stores out of which we should be able to manufacture a decent sized Stanford Torus or O’neill Cylinder. It should be comparatively easy to build an orbital solar farm.
The biggest argument for Moon-first is the proximity to Earth and help. A large population in/on/near Phobos would be Mars’ base of safety. Rescuing Watney/Damon from the surface of Mars would be almost trivially easy.
@@frasercain Compared to surface based solar? Nuclear with its astronomical cost? Keep in mind that these sats transport not just themselves with less required propellant vs. chemical, but also cargo. Solar electric propulsion has been itself proposed as viable just for cargo transport. Using that electrical power to beam microwaves to the surface from Mats orbit involves no great tech leap and was considered viable in the 1960's. I must admit I am both baffled and disappointed by your objection that it is not "simple" enough. Is Starlink too complicated? Power, comm and positioning to any point on the planet at any time immune to single point failure vs. systems that have to be landed on the surface at significant propellant cost and serve only a limited area seems like a no brainer to me. Mars can be a power rich environment eventually able to facilitate beamed power propulsion for faster and more frequent travel to and from Mars..
The lighting makes you look like a panda. :)
We could have the helicopter blow the dust off the solar panels.
What about poo, every astronaut is doing it? What’s radiation shielding abilities of poo? Or for that matter it’s r-value and it’s benefits in slowing down micro meteorites. Just feel there’s got to be a better use than Martian potatoes
Can the helicopter on Mars be used to clean the other rovers by flying just over it and scatter their dust ?
to extend their life ?
No for two reasons:
1) Too many of those rovers' electrical components are dead by now.
2) There are thousands of kilometers away from ingenuity. They're on different continents if you will.
@@Релёкс84 Thanks you.
"The outward expanding force of dark energy is accelerating the galaxies even faster apart." Isn't that just a fancy pseudo-scientific way of saying that we have no idea why the expansion of the observable universe is speeding up? We can't detect dark energy, or dark matter, and we don't know how anything can even interact with them. But we see something unexplainable happening, so we postulate the existence of some magical stuff. Occam's Razor be damned! Whatever!
You may not know it, but there is much more to the story than that. Maybe you should try reading through some actual published paper about dark matter instead of relying solely on what you've heard on youtube.
SN15, hmm… I'm clearly from the future =}
I feel confident SN15 will succeed😑
But 90% not micro making microgravity even less accurate.
It is the "inTernational Space Station" (with a "t") . "Innernational" would be something completely different.
god forbid someone pronounces a word differently
Why don’t you film outdoors anymore?
Bump
Fraser why are you making only question shows? I normal skip those because well not my style to use as podcast video. I was searching for your last "normal or well topic video" thats 7 months ago? Are you going to stop those or really need to watch all q&a video`s for that answer? Well you probably dont give shit about a user.
-i love your topic video`s. Iam more a direct answer man. So short yes no its ok by me.
I'm also doing long and fascinating interviews. The main reason is that I felt the quality of my scripted work wasn't good enough and I wanted to get closer to the sources. So I've been bringing in the actual scientists who are doing this work and taking the conversation to the next level.
The long-term plan is to take this deeper understanding and re-integrate it with my own perspective to tie themes together, but this is where my interests are right now.
If that's not your interest, no problem. Thanks for watching!
Since gravity propagates at the speed of light, its reach is limited to the radius of the observable Universe: 4.4x10^26 meters.
I know that you, like others, are captivated by the idea that the speed of light is the basis of the universe, you and others are wrong. I regret to tell you that the highest speed in the universe is now: 9 x 10 power 12 km / s, Greetings
Frasier Cain = God? No, because God doesn't respond to questions.
Amen.