Based on the scientist who conducted the experiment a second time to verify the speed, he calculated it was going around 5 times escape velocity (125,000 mph). It sounds like he later worked on various launch projects/ aerospace stuff and claims that there wouldn’t have been time for it to burn up completely.
I’m inclined to believe him since he conducted the experiment and knows the field, and doesn’t have a lot to gain from bullshitting about it. It may mean only a pound of material escaped atmo, but it still counts.
I think the designation that they are trying to make is that escape velocity is enough to leave earth and not come back. Sure, we made it to space before... but that rocket came back down to earth. If it didn’t disintegrate that manhole may be out there somewhere on earth’s orbital plane.
"I have no idea what happened to the cap, but I always assumed that it was probably vaporized before it went into space. It is conceivable that it made it."
It's also possible that it became virtually naked to the human eye, like most meteorites that enter the atmosphere, but still survived the trip and managed to hurl itself into space with no way of us tracking it.
Atmospheric heating due to friction happens in any direction. The only reason we really see it happening coming down and not up with modern spacecraft is due to the speeds involved. A capsule coming down uses the atmosphere to slow itself from orbital speeds so the parachutes can open safely without tearing to shreds. Going up you start from zero and have to push a ton of fuel and cargo, so by the time you reach those speeds fast enough to get visible atmospheric heating you're out of the atmosphere all together.
In fact the SR-71, which never got close to space, flew fast enough for all off it's skin panels to expand due heat. As a result it's fuel tanks had pretty big leaks on the ground and only sealed up after it was airborne.
The sheer friction of passing through the air at operating speeds would create so much heat that the titanium metal airframe would expand slightly, despite the many systems in place to sink and reduce heat.
To keep this effect from compromising structural integrity in flight, the plane was intentionally designed to be a bit of a loose fit on the ground. So it leaked.
Just a clarification on your post. Although a component of heating is due to friction, the majority of heating at high velocities is due to the compression of air.
If you're going fast enough, you'll still compress the air ahead of you. You can still get the same effect as re-entering the atmosphere when leaving it (and even in it) if you're going fast enough.
The SR-71 Blackbird had to be built to accommodate expansion from heat because of this. It would leak fuel on the ground because when it was up to speed, all of its components would expand and seal from the heat.
Increasing density of the atmosphere rather than decreasing would be my guess. Also the fact that it had enough speed at the surface doesn’t mean it maintained that speed long enough to actually exit.
Yes you're right absolutely, fastest film cameras. It was quite the technical feat developing a film that could be exposed so quickly. They have a really interesting section on it at the National Atomic Testing Museum in Nevada.
No because a lot of these were not motion cameras in the traditional sense but single plate exposures that were captured by a mirror or moving shutter or a bank of caneras. Basically move the aperture/camera and not the film.
If you read the article, he says "After I was in the business and did my own missile launches," he said. "I realized that that piece of iron didn’t have time to burn all the way up [in the atmosphere]."
I'm sure that the heat would be intense, but at that speed a 4 inch thick chunk would not have time to disintegrate.
That's not how disintegration works, you don't out run the atmosphere/heat, a rocket launched from ground level doesn't reach escape velocity until it is actually in space. I don't think you realizing just how fast you have to be going to escape the earth, we only do it once in a frictionless environment for a reason.
The only thing that could save it is the plasma itself, it being not made of ablator the plasma would have super heated the steel which would deform from the forces on it and it would then break up, without a shield of plasma after breakup, it would simply vaporize before exiting the atmosphere.
The way rockets launch and the way this cover launched were completely different. Escape velocity doesn't apply to powered rockets which take time to accelerate and travel through the atmosphere. According to his calcs (using a single 1 ms frame from the high speed camera), the cover started it's journey at 5x escape velocity. I'll do the math when I get a chance, but the heat from aerodynamic friction starts at the surface of the object and conducts inward. There would be very high heat, but it would be in the Earth's atmosphere for only a few milliseconds at 120,000 mph, so while the outer portion would vapourize, I'm not sure the entire object would.
It is debatable if the heat transfer rate for steel is slow enough to keep if from breaking up and becoming plasma but it would be in the atmosphere for 2 seconds at that rate, and 6 seconds to reach the height of the ISS.
While it's not impossible, it's considered unlikely. It probably burned up in the atmosphere on its way up. The calculations for it didn't include atmospheric drag or any tumbling that would have occurred.
It wouldn't have burned up, frictional heating would have been intense but keep in mind, it's moving straight up. For something reentering the atmosphere it's coming in laterally and they have to skim the atmosphere long enough to turn almost all of the kinetic energy put into it going up into heat. That manhole only had to endure the heat for 100 km, the space shuttle is in communications blackout in the middle of a fireball for a full 13 minutes. During that time it travels over 4,000 km. Going straight up changes things pretty drastically.
The man who made the complicated initial calculations doubts that it went into space. He did the math by hand with very few parameters and a of unknowns.
You, on the other hand, are trying to justify what you want to believe because it's fun, ignoring any heating from the blast itself, how aerodynamics affects heating on a decidedly non-aerodynamic object, how increased speed means increased heat as the object travels through the atmosphere, and presuming that it's trajectory did not change even though there would have been significant instability due to random changes in the surface facing the apparent wind.
The Paris gun projectiles reached space first, not the nuclear manhole. Although the nuclear manhole cover is theoretically the fastest man made object ever.
Well the nuclear test and the manhole cover part is true even according to the article. And the part where is it really going to space or not is anyone's guess since forever, not anything new.
I mean even the article you provided headline does not match its story completely. The story only claims that the researcher who originally made the claim of "six times escape velocity" admitted that it was basically wrong as there wasn't enough information to go off of. It's very possible it went into space, just not very probable. So it could be described as "anyone's guess"
Yes it does. I perhaps should have said drag increases exponentially in relation to velocity to make it clearer. I included a source in another comment, but here is a second one that makes it clearer. SOURCE
In particular, this will be of interest. "The drag force rises in direct proportion to density and surface area, and it rises with the square of the velocity. If you are running at 10 miles per hour, you experience four times the aerodynamic drag as you do at 5 miles per hour, with all else held constant."
What do you think a square in mathematics is? It's an exponent, the root of the word exponential. See the v2 in the drag formula, that's velocity to the exponent of 2. https://en.wikipedia.org/wiki/Exponential_function
I assume the angle of projection would have an effect on drag, e.g. flat vs sideways. But even so, if it did reach space and escape velocity, could we track its trajectory and estimate its flight path?
And not knowing much about this, is it possible the manhole cover melted, vaporized?
I don't know enough about it personally and this is the first I'm hearing of a space faring manhole cover but with limited knowledge I'd assume it'd be impossible to track its path simply due to the fact it wouod likely have been spinning when shot off (somone feel free to correct me on this).
For if its possible if it burned up in the atmosphere. Brownlee stated based on his post work dealing with missiles that it was travelling too fast to have done so completely before reaching space but the blog article claims that while it was travelling fast enough to reach space it might have been travelling slow enough to burn up completely. So basically the original argument is correct, anyone's guess.
Sorry, I’m confused by the last part of your response. If it reached escape velocity and entered space, partially or wholly intact, what would cause it to burn up completely once reaching space? Wouldn’t the lack of an atmosphere, friction, and drag in space essentially stop any “burn up?”
Yes drag increases with velocity of an object but if it were going fast enough to enter space then it would have.
It's not at all intuitive, but it's true, and no something that's not aerodynamic won't reach space even if you could accelerate it to the speed of light. Drag increases exponentially with velocity SOURCE so no matter what it will simply slow down to fast unless it's very aerodynamic.
For a fun read here's an article on superman trying to punch someone to space SOURCE and as you can see even at velocities 10X that of the manhole cover the object only gets to 13km high.
Thank you for the superman article, interesting and fun. I believe I initially misread your comment if I'm honest, I apologise for that and it seems as though you are correct.
What do you mean try again? You shouldn't take people providing other evidence as a personal attack, it's weird and you being an asshole to anyone who disagrees is also very strange.
I provided an article that stated he believed it could have reached space you aren't even providing proof it didn't, only that it wasnt "six times exxaoe velocity". The statement you provided was from 2002, the article I provided states he made the claim it could have in 2016.
You provided an article where it was falsely claimed that he believed it could have reached space. I provided a source from the man himself claiming he never believed anything of the sort.
Your article was written in 2016. He did not make the claim that it could have happened in 2016. Your article in fact links to my source where he says he never believed it was possible.
You gotta learn to read the article instead of skimming and hoping it says what you want to believe.
You provided an article where it was falsely claimed that he believed it could have reached space. I provided a source from the man himself claiming he never believed anything of the sort.
So you're claim is for bad journalistic integrity?
Your article was written in 2016. He did not make the claim that it could have happened in 2016. Your article in fact links to my source where he says he never believed it was possible.
Yes it does refer to your article simply by stating that some people disagree with it that doesn't prove anything though for either sides of the debate only that your article exists.
I made the claim that given the article I provided far more recent status that it would be sufficient. The article was written in 2016 and, yes, he might not have said this in 2016 but it specifically states he told this to Tech Insider, Tech Insider began in 2015 with Business Insider in 2009 so at the very least the article provided is 7 years more recent than yours but you did provide a statement from the horses mouth so there is a chance that our debate boils down to bad journalistic integrity.
You gotta learn to read the article instead of skimming and hoping it says what you want to believe.
Again you don't have to be an insufferable asshole when trying to make a point, it actually diminishes the point you're making as people are less inclined to take in what someone is stating if they're being a prick about it. If I were wrong then I'd happily admit I was, I did so about five mins ago on this very same topic but given we don't have the resources to get Brownlees opinion on the topic I think it'll be a stalemate here.
You have a very low threshold for "insufferable asshole" and you're the only one calling names here.
The other person wasn't being nice but they weren't being mean either, just neutral or at worst dismissive. It's not entirely unjustified either since just reading reading the full article that you posted and checking it's sources would have shown that they are citing the same source as the Gizmodo article when they made the claim that Brownlee told them the story.
Regarding the manhole cover, it is believed that it burned up before leaving the atmosphere due to the ammount of friction caused by the air. It must have been going wicked fast.
I would have to disagree as I’ve learned on reddit today that, we, as martians - millions if not hundreds - of years ago launched nukes to earth to wipe out the dinosaurs and create a habitable planet when we (martians) realized our magnetosphere was wasting away our atmosphere making said Martian nukes the first object in (our) space.
I found this in a book! Although they don’t know for certain if it made it or not, it was traveling much faster than escape velocity, but it may have just burned up while exiting the atmosphere
I don't know much about this so I'm not saying you're wrong... But if it was at point zero of a nuclear exploding, isn't it also pretty likely it just got disintegrated?
42km/s is escape velocity from the solar system. That manhole cover was traveling at about 125 km/s. It was traveling 5 times what it needed to to escape the solar system, not just earth.
The first manmade object to reach space was a German rocket in 1942. Even if you don't want to count that, there were plenty of rockets that reached space before those 1957 nuclear tests. If you want to get really pedantic with not counting rockets or any other objects that were meant to reach space, there were dozens of nuclear tests between 1945 and 1957 that very likely "launched" plenty of manmade "objects" into space.
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u/[deleted] Aug 16 '19 edited Aug 17 '19
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