Passing stars changed the orbits of planets in the solar system
universetoday.com
universetoday.com
The paper, linked, https://iopscience.iop.org/article/10.3847/2041-8213/ad24fb, does go into the chaotic behavior and why it's all kinda sorta made up.
What is uncertain is only which were the changes, i.e. which were the orbits of the planets prior to the star passing.
The changes must have been very small, but they must have existed.
The point of the paper is that this stellar passing and others like it increase by a non-negligible amount the uncertainty of the simulations that attempt to determine accurately the planetary movements in the distant past of the Solar System, at scales of tens of millions of years.
The star HD 7977 is slightly bigger and brighter than the Sun, so when it has passed at the minimum distance there are chances that it was noticeably brighter than Venus.
The problem is, as the paid readers fall, they are forced to use clickbait titles to attract more on line readers to click ads. Imagine a newspaper founded in 1831, using titles like, "You will never guess what she said next" as a main headline.
The same here, who is going to click on "Passing stars may affect the orbits of our planets"? They know exactly what they are doing and it's not about the scientifically literate.
I understand that real journalism must be paid for, but allowing megacorps to buy up all maintream media was a huge mistake and now they are all corporate mouthpieces.
I don't know what the answer is, but trusting 'journalists' of today is not it.
The head of journalism at my college warned us of this over a decade ago, and he didn't have the answer either. They lost their ethics in search of clicks and clout and cry foul when they aren't believed. They use divisive language, outright lie, holy crap this election cycle will be a shitshow. There's no unbiased truth finders anymore.
The ones I feel sorry for are the real journalists drowned out by the fake.
Some are, some aren't. Just like some programmers are real programmers and others are not, and some managers are real managers and others are not. The world is full of posers but that doesn't mean there aren't people that hold the title + the ethics that come with it dear. They're a minority, but they've always been a minority, that didn't change at all.
> Public trust in media is at an all-time low for a reason.
It mostly is because there are well funded political groups that incessantly undermine the public trust in the media. Because the last thing they want is for their deeds to be properly exposed and investigated.
> I understand that real journalism must be paid for, but allowing megacorps to buy up all maintream media was a huge mistake and now they are all corporate mouthpieces.
> I don't know what the answer is, but trusting 'journalists' of today is not it.
Well, one thing that could be done is to seriously limit ownership of media by global empires. The likes of Murdoch have done untold damage to the world in the pursuit of some green paper.
> The head of journalism at my college warned us of this over a decade ago, and he didn't have the answer either.
Yes, it is a problem. And given the cost of good investigative journalism it is in fact unbelievable that there are still people doing this because they see it as their calling. And I'm mighty impressed with that and do not accept the broad brush with which they too are being painted. In every country you can find journalists that operate with integrity and that are not to be muzzled by corporate interests. They're real heroes too because in plenty of places that will get you ostracized, beaten up, blacklisted or murdered.
> They lost their ethics in search of clicks and clout and cry foul when they aren't believed.
Some. Not all.
> They use divisive language, outright lie, holy crap this election cycle will be a shitshow. There's no unbiased truth finders anymore.
There are, just not all that many, but they do exist.
> The ones I feel sorry for are the real journalists drowned out by the fake.
So, it seems we agree they exist. My solution is pretty simple, I seek out the journalists whose work I trust and I try to get my information about country A from any source except the ones in country A because they likely will not be objective. That's a hack and a workaround but it seems to work quite well.
The problem is that poor journalism influences the masses. And in a democracy, the masses' opinion is assigned a higher decision-making weight than is the opinion of the informed minority.
"the uncertainties of Earth’s past orbit make it difficult to be confident more than 50 million years. And that has a significant impact on paleoclimate studies."
One realization I had was how orbits were fragile and how easily you could shift them with influence from very far away.
Another realization- gravity is weak, but it decreases over a huge distance compared to other forces we normally experience in human scale.
The strong and weak interactions are only significant on very short distance scales; from the standpoint of "force laws" you can think of them as having an exponential decay with distance that makes them drop off to essentially nothing by the time you get to distances much larger than the size of an atomic nucleus. (That's an oversimplification, but it's enough to see why you can ignore them on astronomical scales.)
The plasma itself is magnetic, so the magnetic force itself is not acting over multi-light-year distances; the material carrying the magnetism is traveling over those distances and bringing its magnetism with it.
Also, this magnetism doesn't affect the orbits of planets or stars; my original statement was focused on what affects those things.
Maybe a better electromagnetic example would be radio signals from pulsars, which are enormous and travel great distances and still provide measurable signals even if they are light years away. We cannot on earth measure the gravity of these objects, nor the atomic forces, but we can readily meausure their electromagnetic sprayings.
As I understand it, planetary magnetic fields influence solar winds; stellar ones structures in the galaxy; etc.
I’d really like to learn more (preferably, with numbers).
I know from talks that filaments[0], galactic lobes[1], structure of arms[2], etc relate to EM — but finding anything at the layperson level is basically impossible. Just short blog posts, but no real explanation of how this all relates or what drives it.
Harumph, I say!
[0] - https://www.livescience.com/radio-filaments-milky-way-center
[1] - https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10918
[2] - https://blogs.nasa.gov/sofia/2022/04/05/make-no-bones-about-...
To hint at any role of E-M in the large-scale evolution of the universe is a good way to eliminate any possibility of a research grant. Probably this is just because the people deciding don't want to be obliged to learn how to evaluate whether the research program makes any sense. So, plasma fluid dynamics work normally is studied only at the scale of an individual planet or star, or at most a galaxy.
SOFIA, the telescope carried in a Boeing 747, lost its funding in part because mainstream astronomers found its unique capability of mapping magnetic polarization uninteresting.
Yes, I was oversimplifying somewhat. Magnetic fields don't affect things like the orbits of planets or stars. But they do have other effects on astronomical scales.
I've never heard an explanation of the strong or weak forces that I actually "get" enough to understand their distance effects.
I thought this was excellent (in all ways) but particularly for your question: https://www.youtube.com/watch?v=UYW1lKNVI90
Edit: so for weak, I think I understand that "photons are massless, so are only subject to the inverse-square law; weak bosons have mass, so are also subject to decay". But that doesn't explain to this dummy how the strong force works, since gluons are also massless (... though mesons are not? but they're not fundamental).
We're talking about stellar visitors that arrive every 20 million years or so. We have no evidence of any civilization that lasted much more than 1,000 years.
So you're going to hitch a ride with a stellar visitor, with a view to colonizing the galaxy? Suppose the visitor comes as close as a few thousand AU, and the colonist ship can reach it in a hundred years or so; cool. But how long before the visitor reaches the next star on its tour? That's going to be millions of years.
So the colonists set up camp on a planet orbiting the visitor; the hypothesis is "a very long-lived" civilization, so we assume they have brought their knowledge with them to this camp, from the home planet, and are able to conserve it (strong assumption). But for tens of millions of years?
Civilizations evolve much more quickly than organisms, if Earth history is anything to go by. It seems far-fetched that a civilization might survive the evolution of the underlying organism; there's something Canute-like about trying to preserve a civilization in the teeth of genetic evolution. Evolution is going to happen, even during the initial journey to the visitor.
I'm very sceptical about this notion of "very long lived extraterrestrial civilizations".
Eventually there would be selection for colonies that can produce faster and/or longer lived colony ships, so they can plant new colonies faster. This will eventually shade over into the more conventional galactic colonization scenarios where stars can be treated as near stationary.
Yeah, but would anyone do that to an entire civilization? Evolution leads to greater 'fitness' - improved adaptation to the environment. The travellers are jumping from $HOME_PLANET, into a generation ship, onto a new planet presenting novel adaptation challenges. That planet's star-system then eventually sets off on a long journey, until it encounters a new star. Each of these stages takes many times the time humans have existed on Earth. If you consider only modern humans, we've only been around for 50,000 years, maybe.
And "modern humans" isn't a civilization; it's really all of the different, successive human civilizations.
If you could imagine that, in addition to making stone tools and animal-hide clothes, neanderthals had also learned how to freeze evolution, do you think those guys would be well-adapted to a planet-hopping future? I don't.
There's been this great (relatively) short story, both humorous and profound, by Stanisław Lem; "The Twenty-first Voyage" in "The Star Diaries". It's based on that exact premise.
There could be a good measure of good luck needed too. eg the spaceship is lucky enough to get some gravitational assistance from a large body or two in the target system
If the time between encounters is a million years, at 30 km/s the stars will have separated by 100 light years.
Given the likely time scales, do you reckon that'd be challenging?
To me, that sounds like an awful lot of acceleration would be needed.
If you could teleport a fully fueled Saturn V into orbit, it could speed up by about 18 km/s. More if you reduced the payload.
Of course going from 18 to 30 exposes you to the tyranny of the rocket equation: to go faster you need more fuel, which makes your rocket heavier, which means it needs more fuel, which makes your rocket heavier, ... Any small efficiency increase matters a lot here. It might be possible with today's tech if you build the rocket in orbit (which gets rid of aerodynamic constrains), or alternatively with orbital refueling and a couple more decades of progress in more efficient engine types (which you could greatly accelerate by throwing money at it).
Solar sails released at perihelion can also achieve very high speeds.
Slowing down in the target system could be done with solar sails or electrodynamic sails (working on the stellar wind).
Ion or plasma engines are another possibility, with nuclear power plants.
https://www.wolframalpha.com/input?i=%2830+km%2Fs%29%2Fg&ass...
At least I think that's what they meant. It's an interesting idea for sure.
A star inside the Oort Cloud might start another inner system bombardment.
This blew my mind. I never considered that stars are moving relatively each other in this way. Or more precisely, what it meant for our solar system.
The question is, can you make a ship fast enough to catch a star going past, or do you have to launch ahead of time. And do you have enough time in either case to decide if this one way trip is suicide or not.
Practically the window of opportunity for a favorable launch may not might not be that different than launching for Proxima Centauri. But at least you can soak up solar power and mine resources while you wait, instead of sitting in the dark the entire time.
A few years ago, research using Gaia data indicated that the last such close encounter was about 70,000 years ago, when the star WISE J072003.20-084651.2 — also called Scholz’s Star, after the discoverer — passed just 0.8 light-years from the Sun.
- https://www.syfy.com/syfy-wire/bad-astronomy-several-stars-h...
[1] https://en.m.wikipedia.org/wiki/Nemesis_(hypothetical_star)