Astronomy & Space Exploration
- Thread starter MrMarcello
- Start date
Sadly that's art
Here is the truth
https://solarsystem.nasa.gov/resources/17792/impact-site-cassinis-final-image/
Here is the truth
https://solarsystem.nasa.gov/resources/17792/impact-site-cassinis-final-image/
Gonna miss Cassini. It's journey is something close to a sci-fi novel, especially era when it investigated black spots on Jupiter after fascination that led to allegations it could be a black hole.
I remember some of the coolest theories around the earlier internet, that NASA tried to ignite the planet's gas to create 2nd sun.
Good times.
I remember some of the coolest theories around the earlier internet, that NASA tried to ignite the planet's gas to create 2nd sun.
Good times.
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Gonna miss Cassini. It's journey is something close to a sci-fi novel, especially era when it investigated black spots on Jupiter after fascination that led to allegations it could be a black hole.
I remember some of the coolest theories around the earlier internet, that NASA tried to ignite the planet's gas to create 2nd sun.
Damn, the people who suggested that definitely did do not understand physics
Dammit
Gonna miss Cassini. It's journey is something close to a sci-fi novel, especially era when it investigated black spots on Jupiter after fascination that led to allegations it could be a black hole.
I remember some of the coolest theories around the earlier internet, that NASA tried to ignite the planet's gas to create 2nd sun.
I find the potential of JWST much more appealing than pics inside the solar system.
For sure JWST saves more energy / fuel and it's overall more sophisticated technology, however Cassini been there, done that and ended in style.
Would love to see Cassini II someday being partly an AI, making more than few navigation decisions on it's own... still won't be iconic as Cassini and all the legends & other fan fictions around it. Definitely worthy of it's own book.
The Gaia mission is doing some immensely cool stuff.
And a picture:
Caption: "The Milky Way in four maps: data from the Gaia spacecraft show the speed at which stars move towards or away from us, known as radial velocity (top left); their radial velocity and proper motion, or how they move across the sky (bottom left); their chemical make-up (bottom right); and the interstellar dust (top right)."
Now just imagine that the universe consists of millions (billions?) of similar galaxies and cue the Douglas Adams quote about the universe being vastly, hugely, mind-bogglingly big...!!
Accessible article: Mega-map of Milky Way adds depth to stars’ motions (nature.com)Nature Briefing said:
And a picture:
Caption: "The Milky Way in four maps: data from the Gaia spacecraft show the speed at which stars move towards or away from us, known as radial velocity (top left); their radial velocity and proper motion, or how they move across the sky (bottom left); their chemical make-up (bottom right); and the interstellar dust (top right)."
Now just imagine that the universe consists of millions (billions?) of similar galaxies and cue the Douglas Adams quote about the universe being vastly, hugely, mind-bogglingly big...!!
Interesting bit about alien life. Part of a much longer interview
The Gaia mission is doing some immensely cool stuff.
Accessible article: Mega-map of Milky Way adds depth to stars’ motions (nature.com)
And a picture:
Caption: "The Milky Way in four maps: data from the Gaia spacecraft show the speed at which stars move towards or away from us, known as radial velocity (top left); their radial velocity and proper motion, or how they move across the sky (bottom left); their chemical make-up (bottom right); and the interstellar dust (top right)."
Now just imagine that the universe consists of millions (billions?) of similar galaxies and cue the Douglas Adams quote about the universe being vastly, hugely, mind-bogglingly big...!!
I am sure that we are going to learn a whole lot more about our universe in the coming years with the JWST.
And while we will never know, our universe could well be just one of an infinite number of other universes, each with differing structures and differing laws of physics.
I often walk along a fabulous beach in Somerset, Burnham on Sea to Brean Down. One of the longest stretches in Europe. And look down at the seemingly endless sand. And think of the saying that - there are more stars in our universe than grains of sand. That is a mind-blowing thought.
Absolutely. Thinking about the universe and its time-scale ultimately always just weirds me out.
The great part is that all these programs complement each other, it's not competition. Webb will show awesome new stuff, and Gaia will continue to do its thing for our galaxy. There's still so much to learn!
HUBBLE DETERMINES MASS OF ISOLATED BLACK HOLE ROAMING OUR MILKY WAY GALAXY
https://hubblesite.org/contents/news-releases/2022/news-2022-001
Astronomers estimate that there should be 100 million black holes roaming among the 100 billion stars in our galaxy. But since black holes emit no light of their own, they are extremely difficult to detect. Now, astronomers have at last come up with clear evidence for finding one in a needle-in-a-haystack search among a blizzard of stars seen toward the galactic center. The light from a star far behind the black hole was momentarily brightened and deflected by the black hole passing in front of it. This was a long and painstaking measurement that the Hubble Space Telescope's exquisite resolution is well-suited for. The black hole's powerful gravitation left a unique fingerprint on the deflection of starlight, eliminating other potential gravitational lensing candidates.
No need for us to worry because the black hole is 5,000 light-years away. But, statistically, this detection means that the nearest wandering black hole to Earth could be no more than 80 light-years away.
https://hubblesite.org/contents/news-releases/2022/news-2022-001
Astronomers estimate that there should be 100 million black holes roaming among the 100 billion stars in our galaxy. But since black holes emit no light of their own, they are extremely difficult to detect. Now, astronomers have at last come up with clear evidence for finding one in a needle-in-a-haystack search among a blizzard of stars seen toward the galactic center. The light from a star far behind the black hole was momentarily brightened and deflected by the black hole passing in front of it. This was a long and painstaking measurement that the Hubble Space Telescope's exquisite resolution is well-suited for. The black hole's powerful gravitation left a unique fingerprint on the deflection of starlight, eliminating other potential gravitational lensing candidates.
No need for us to worry because the black hole is 5,000 light-years away. But, statistically, this detection means that the nearest wandering black hole to Earth could be no more than 80 light-years away.
New disaster movie inc..
Roaming seems a strange choice of words.
Suggesting that they are moving around randomly?
What is a black hole ? I mean relative to Earth. If Earth went into a giant black hole what would happen?
I can tell you from my first-year astrophysics module at university that spaghetti happens
Big explosion that cant be seen?
It's not an explosion, but is the stretching of everything including spacetime. It refers to the stretching / tearing apart of matter, which probably wouldn't be a pleasant experience.
The biggest supermassive black holes wouldn't do this as the gravitational pull isn't so strong (as they're literally so big it's spread out)
What would happen if you fell into a black hole? Spaghettification explained (rmg.co.uk)
The SpaceX Super Heavy is getting nearer its first launch later this year. This is the launch vehicle for Starship which is being used by NASA to land on the moon and the vehicle SpaceX want to use for Mars.
The amount of rocket engines is just ridiculous.
The amount of rocket engines is just ridiculous.
Its an everything bagel .. sorry
A black hole is any mass that is soooooooooooooooooooooooo (can't emphasize this enough) densely packed that...
- Its collapses upon itself with near infinite gravity at the center (a so-called singularity (which doesn't really exist and is more of a representative term or mathematical artefact) with near zero volume (well not near zero but undefined)).
- Space-time (i.e., the underlying fabric of the universe which gets curved by anything with mass) gets near infinitely curved in its vicinity (like a bottomless well) according to general relativity.
- The constituent material or things that have fallen into it or even electromagnetic radiation cannot escape because they have fallen into the inescapable bottomless well (where you need near infinite force to break free).
Theoretically, any object with mass can be transformed into a black hole if the stuff within it is very, very, very (again, can't emphasize this enough) tightly packed and it collapses into a singularity with near zero volume and near infinite density/gravity and curves space-time to a near infinite degree. The size of the event horizon (which is the dark void effect that you see in imagery or popular artistic renditions of a black hole, with red-shifted light and maybe accretion disks, astrophysical jets, relativistic streams around it) can be calculated with the Schwarzschild radius equation. To get a sense of just how densely things will be packed together to reach such a stage, you could become a black hole for example — but a really puny one with the radius of your event horizon being much less than the nucleus of a single atom (and you will evaporate and explode in approximately 0.0000000000024 seconds, but that's another matter!) The Earth (with a mass of approximately 5,974,000,000,000,000,000,000 tons) could similarly become a black hole — the radius of its event horizon will be slightly less than 1cm. And so on with anything that has mass.
But in practice (as far as we know) the body will have to be at least 3 times the mass of the sun (or roughly 1 million times the mass of the Earth) to have the conditions to violently transform into a black hole — which means that you're mostly talking about hypernovae at the end of a massive star's life cycle when it runs out of fuel (where the gravity at the center overcomes the outward radiation of the fuel and you get a rapid collapse). Even bigger super/ultra-massive ones were likely formed by the direct collapse of nebulae (so they skipped the stellar phase), or maybe vacuum decay?
Depends on the type of black hole, the space-time geometry and gravitational gradient, and other properties. If it's a true giant (like Sagittarius A* at the center of the Milky Way...which has an event horizon that is roughly 25 million kms across and weighs as much as 4 million Suns (but still faaar from the biggest black hole observed)), the Earth will fall into the event horizon, and after that — well, all the physics and mathematics of humanity break down. What we can say in a roundabout way is that it gets reconstituted, becomes one with the singularity, ceases to exist in any recognizable form and get forever locked away (and will not interact with anything else in the observable universe for the rest of time). A terrible fate, but things will be relatively serene even when you are approaching the event horizon (so there's a short-term upside?) If it's a sufficiently smaller one, the Earth will not explode while approaching the event horizon — but get violently ripped apart and atomized by tidal forces, and fall in like a stream (as the gravitational pull at one point will be much different than others) prior to getting reconstituted, becoming one with the singularity, ceasing to exist in any recognizable form and getting forever locked away (not interacting with anything else in the observable universe for the rest of time).
It's worth saying that Sagittarius A* is ridicuously big, but M87 located in Virgo is so big that it would take days for light to cross the accretion disc with a mass of 6.5 billion suns and that's only the biggest black hole observed so far.
https://www.chron.com/news/houston-...t-NASA-moon-crash-country-origin-17273903.php'Mystery rocket' that crashed into the Moon baffles NASA scientists
So far, no space exploring nations have claimed responsibility for the rocket.
NASA has discovered the crash site of a "mystery rocket body" that collided with the Moon's surface earlier this year. The impact left behind a widespread "double crater," meaning it wasn't the average rocket.
However, since its crash landing, none of Earth's space-exploring nations have claimed responsibility for the mysterious projectile, leaving NASA scientists baffled as to who was behind its launch. New images shared on June 24 by NASA's Lunar Reconnaissance Orbiter show the unusual impact site.
That was a good read tbh.
I think is fair to say that terms like singularity and infinities are not meant to be literal. It only indicates that the current set of equations, mostly from general relativity, run into infinities inside a black hole. In those cases the equations tend to be wrong.
A massive dying star need to give account of anything that is been created quanta by quanta. You can not take a finite ammount of stuff and created something infinite or a true singularity. In theory a finite ammount of energy can expand forever, but this is another thing.
Its impossible to know what happens in the region we call singularity. Its true that a short distances you can create particles out of nothing. Maybe gravitons do exist and a infinite number of them are created there with no limitations because time behave strangely, is space-like and mutidirectional inside the black hole.
But the idea of singularity and infinity density looks more like the so called ultraviolet catastrophe, when equations were showing an infinite energy output from black bodies, what obviously couldn't be true or the universe would probably be a plasma, and the solution for that problem leads to the major development of quantum physics.
Big day on Tuesday. They've done a good job promoting this mission so far so I expect they'll make sure the first images are sufficiently spectacular.
https://www.nasa.gov/image-feature/countdown-to-the-webb-telescopes-first-images
https://www.nasa.gov/image-feature/countdown-to-the-webb-telescopes-first-images
Easily one of the most interesting things I have read, on this forum, ever.
I am fascinated with this whole subject, Physics and Cosmology. And easy to read and comprehend articles only increase my interest.
My particular fascination is about the birth of our Universe, if that is the correct term.
Can I ask if it is your view that as our Universe continues to expand, as will Black Holes that eventually, Black Holes will dominate, consuming everything including themselves.
And ultimately, there could be one single mega Black Hole which could determine the fate of our Universe?
How advanced is the Chinese space program?
I'm not him (I'm me!), but it doesn't really work like that. Unless the expansion of the universe reverses somehow, all matter is never going to gather in one spot. We're actually already basically forever separated from the vast, vast majority of the Observable Universe, let alone the rest of it. Currently we're "only" gravitationally bound together with the few dozen galaxies that make up the Local Group. Eventually we'll all be one big, happy galaxy. And any intelligent life that forms in that supergalaxy will probably never be able to figure out about the Big Bang and the expansion of space, since all other stars will have faded from view (redshifted beyond any possible detection). They'll logically conclude that their galaxy is the entire Universe, which is static and eternal.
Black holes will be the last things left in the Universe, but that's because they last so damn long.* Black holes aren't hoovers/vacuums, they're not flying around sucking up everything around them. If the Sun was replaced by a black hole with the same mass, we'd just continue in exactly the same orbit. Earth would become a giant snowball, that's all. No biggie.
*There's a very cool idea related to this. When all the stars have gone out, and all we're left with are black holes, it might be possible for life to survive around black holes. There's a Kurzgesagt video on it:
Tangentially related, another cool Kurzgesagt video:
Thanks very much for taking the time to post this which I will certainly look at.
I realised when I wrote the post that what I was saying was incorrect due to the expansion of our Universe.
But what I was thinking of at the time was that there is a theory that our Universe could go through a series of expansions and contractions through its life cycle.
That's a theory (or probably more of an hypothesis, really), sure. It seemed a little bit more likely before, now we're pretty sure the Universe is just going to keep expanding. What you're describing would be something like the Big Crunch, where expansion would slow down, then stop and finally reverse. All the matter in the Universe would meet in a point in space (well, not really in space, but you get the idea) in some sort of reverse Big Bang (which some hypothesize could lead to a new Big Bang, like you're saying).
I think the heat death of the Universe is the most favoured theory at the moment, where the expansion goes on forever but never overpowers gravity on a local level. But there's also something called the Big Rip. If the rate of acceleration ramps up, that could end with the building blocks of the Universe being literally ripped apart. If that one is the case, we're probably a lot closer to the end than if it's the former.
Again. Appreciate your inputs which I always read with great interest.
In the case of the heat death scenario, what happens to all the energy and matter.
Does it just all become spread out due to the continued expansion, never to become anything ever again as the ripples in the fabric of the Universe flattering out?
Simplified, I think that's about right. It's the maximum state of entropy, where there's basically no potential for anything more to happen. Everything has just been so spread out, which is why we're also talking really long time-scales here.
No one knows for sure because of the secrecy involved in certain CNSA departments. Looking at what the Chinese space program has accomplished thus far, or is going to in the near future:
- They soft landed on Mars and deployed the Zhurong rover in 2021 (the USSR's rovers failed and the USA was first successful in 1996).
- They deployed the Yutu lunar rover in 2013 (which the USSR and the USA did in the 1970s).
- The Tiangong Space Stations were or have been in orbit for a decade-ish (which the USSR and the USA did in the 1970s).
- They have yet to send taikonauts to the moon (which the USA did with Apollo 11 in 1969).
- The Five-hundred-meter Aperture Radio Telescope has been operational for 2 years, and makes independent cosmological discoveries.
- The Xuntian telescope is going to be launched next year and is comparable to Hubble (which was launched in 1990).
As regards future extrapolations, conservatively, you could say that they need a few decades to mature, improve the infrastructure, expand and streamline their scientific base (with more Qian Xuesens and Hsue-Chu Tsiens), and catch up with the preeminent space power (speculatively of course, we don't really know). As of right now, they've mostly made use of pre-existing technology, frequently leaned on Russia for expertise, and are not consistently leading the pack in terms of advancements (like SpaceX, Northrop Grumman, Blue Origin, and other privately owned enterprises in recent years...aside from NASA (which is pretty well funded in comparison with other space agencies, even now)).
But they will inevitably get there, as they've done in other industries — no doubt about that. And the growth could be rapid because precedents and blueprints are available, the CCP is ambitious in terms of policy-making and implementation, and funding will be plentiful as their economy continues to balloon (especially if the private environment is further liberalized). But genuine innovation and finding solutions to seemingly insurmountable problems will be the most challenging part (as it is for everyone else), and what will truly define the country's overall space program in the future. Just hope that they put their knowhow and unparalleled mass production capabilities to good use (like planned geostationary solar power stations), and it doesn't lead to a bipolar space race with militaristic undertones and provincial attitudes.
P.S. That's just my opinion, others could give you a more comprehensive overview.
Cheers.No one knows for sure because of the secrecy involved in certain CNSA departments. Looking at what the Chinese space program has accomplished thus far, or is going to in the near future:
And so forth...
- They soft landed on Mars and deployed the Zhurong rover in 2021 (the USSR's rovers failed and the USA was first successful in 1996).
- They deployed the Yutu lunar rover in 2013 (which the USSR and the USA did in the 1970s).
- The Tiangong Space Stations were or have been in orbit for a decade-ish (which the USSR and the USA did in the 1970s).
- They have yet to send taikonauts to the moon (which the USA did with Apollo 11 in 1969).
- The Five-hundred-meter Aperture Radio Telescope has been operational for 2 years, and makes independent cosmological discoveries.
- The Xuntian telescope is going to be launched next year and is comparable to Hubble (which was launched in 1990).
As regards future extrapolations, conservatively, you could say that they need a few decades to mature, improve the infrastructure, expand and streamline their scientific base (with more Qian Xuesens and Hsue-Chu Tsiens), and catch up with the preeminent space power (speculatively of course, we don't really know). As of right now, they've mostly made use of pre-existing technology, frequently leaned on Russia for expertise, and are not consistently leading the pack in terms of advancements (like SpaceX, Northrop Grumman, Blue Origin, and other privately owned enterprises in recent years...aside from NASA (which is pretty well funded in comparison with other space agencies, even now)).
But they will inevitably get there, as they've done in other industries — no doubt about that. And the growth could be rapid because precedents and blueprints are available, the CCP is ambitious in terms of policy-making and implementation, and funding will be plentiful as their economy continues to balloon (especially if the private environment is further liberalized). But genuine innovation and finding solutions to seemingly insurmountable problems will be the most challenging part (as it is for everyone else), and what will truly define the country's overall space program in the future. Just hope that they put their knowhow and unparalleled mass production capabilities to good use (like planned geostationary solar power stations), and it doesn't lead to a bipolar space race with militaristic undertones and provincial attitudes.
P.S. That's just my opinion, others could give you a more comprehensive overview.
Looks like the eye of Sauron.
Super cool and exciting to see what images it is able to capture
Would be typical if they had about 3000 single points of error that they get through to get it into space, and then it gets twatted by a bit of dust and is useless.