Passing stars changed the orbits of planets in the solar system

https://www.universetoday.com/165727/passing-stars-changed-the-orbits-of-planets-in-the-solar-system/

by clockworksoul • 2 years ago

89 72 2 years ago

Great short article. Takeaway: because of ancient star flybys

"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."

jvanderbot3• 2 years ago

That's actually fascinating! Among other things passing stars can do, I imagine, is knock comets out of the Ort cloud? So speaking of dinosaurs...

hinkley2• 2 years ago

The butterfly effect, where the 'butterfly' is a stellar object.

marsissippi2• 2 years ago

Lisa Randall's book "Dark Matter and the Dinosaurs" has that vibe (not about passing stars, but about the solar system passing through an area of the galaxy thick with dark matter - but the imagined impact is the same).

vardump• 2 years ago

Maybe dinosaurs jumped to another star that time and arranged some fireworks to ensure no one will follow?

collaborative• 2 years ago

I often think about how stars come within 1 light year of our Sun every 300,000 years. It's pretty wild. And then I have to worry about rogue planets, meteorites, and obfuscated stars going supernova. What are the odds we're here?

pfdietz6• 2 years ago

This also means very long lived extraterrestrial civilizations can colonize the galaxy with slow very short range starships. Just wait for stars to come within a fraction of a light year and send over ships at 1% of the speed of light (or even slower). The star will move away, and it also becomes a target for close approaches of stars. The number of colonized stars grows exponentially (if gradually) until most stars have been colonized.

alserio• 2 years ago

Sorry, I'm not getting this. The star will move away from what? Wouldn't the spaceship move with the star? I apologize if I'm misinterpreting what you said

justinclift3• 2 years ago

At a rough guess, even with an approach between stars that's very close, the difference in velocities between them may make for swapping between the two systems near impossible.

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

denton-scratch2• 2 years ago

very long lived extraterrestrial civilizations

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".

mongol• 2 years ago

Right now the star is about 250 light-years away, but 2.8 million years ago it passed within 30,000 AU or half a light-year of the Sun. It may have passed as close as 4,000 AU from the Sun.

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.

silverquiet• 2 years ago

Sometimes people talk about hypothetical generation ships and the ethics of bringing children into such a situation where they will be expected to continue the mission throughout their lives. What’s funny is that in some sense we’re already on quite a large starship wondering near aimlessly through the galaxy. Obviously we could be treating it with much greater care than we currently are.

zbaxrl• 2 years ago

Gliese 710 will be at a 0.16ly distance in 1.3 million years. Well within the Oort Cloud.

https://en.wikipedia.org/wiki/Gliese_710

GMoromisato• 2 years ago

Quick! Someone write a sci-fi screenplay set in that time period!

A star inside the Oort Cloud might start another inner system bombardment.

andsoitis• 2 years ago

how stars come within 1 light year of our Sun every 300,000 years.

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...

LASR• 2 years ago

In university I coded an N-body simulator and visualizer. This was back before when we had so many games that exist now. It taught me a lot about orbital mechanics.

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.

jvanderbot3• 2 years ago

Does gravity decrease more slowly than other forces, or is it so weak that the gravity sources we feel are enormous and therefore have long radii of non-negligible effect, or is it something else?

o11c2• 2 years ago

Gravity doesn't cancel like the electromagnetic force, despite otherwise decreasing at the same rate.

I've never heard an explanation of the strong or weak forces that I actually "get" enough to understand their distance effects.

pdonis4• 2 years ago

Gravity and electromagnetism both obey inverse square laws, but electromagnetism is negligible on astronomical scales because positive and negative charges cancel so astronomical objects are electrically neutral (or close enough to it that electromagnetic effects are negligible).

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.)

mianos2• 2 years ago

The title is wrong. "Passing Stars Could, and Maybe Have, Changed the Orbits of Planets in the Solar System'. I guess they are going by the old journalist's adage, never let the facts get in the way of a good story.

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.

NotSammyHagar2• 2 years ago

The other rule of journalism is the author of of a piece doesn't write the headline.

adaml_623• 2 years ago

One day sub-editors will be named and shamed for the headlines they excrete onto the world

vikingerik• 2 years ago

Well, in the "technically correct" department, the stars all do, even if it's on the order of attometers or whatever. It's set up to pass the fact-checking, so yeah, that's just about the standards of modern journalism.

jacquesm5• 2 years ago

I'm sick and tired of the more or less concerted attack on journalists with every opportunity. Bad media have been around as long as there have been media, if you think the standards of modern journalism have dropped you are either looking at things through a very local lens or simply not well informed about mass media through the ages. But quality content exists if you're willing to pay for it, which is how it has always been. Free content, whether in print or on the web can be very good but as a rule if it is brought to you by a commercial entity you have to always question the value of the words and their relation to commercial interests.

rob74• 2 years ago

...or in this case, "state theories as if they were facts if it makes a good headline"?

adrian_b• 2 years ago

Given how close the star HD 7977 was 2.8 million years ago, many times closer than any star today, it is pretty much certain that its passage has perturbed the orbits of the planets.

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.

skywal_l• 2 years ago

In the same vein, Gliese 710 will pass even closer at 0.16 ly from the Sun in 1.29 million years which add uncertainty to the simulation of the distant future.

daxfohl• 2 years ago

The picture is misleading. Scholz's star is a dwarf and was not visible by the naked eye even at closest approach, unless it happened to flare at the time (and even then would have been like the thousandth brightest object in the sky).

https://www.pas.rochester.edu/~emamajek/flyby.html

jandrewrogers• 2 years ago

As an interesting related tangent, one of the largest asteroids in the solar system, Juno (~250km diameter), changed its orbit in the 19th century and there is no evidence what caused it.

pif• 2 years ago

Talks about an event several dozens of million years ago. Shows a picture of a hominid looking at a star. Keep up the good work!

lupusreal• 2 years ago

I wish they'd put that "little detail" prominently in the title. Without it, this becomes fodder for people who believe in astrology. Maybe this was the idea...

ctchocula• 2 years ago

If you're interested in this topic, you might also be interested in the idea that there is a Brown Dwarf hidden near our solar system that causes periodic extinctions on Earth, because it periodically messes up the comet shield provided by the Sun and gas giants.

[1] https://en.m.wikipedia.org/wiki/Nemesis_(hypothetical_star)

Passing stars changed the orbits of planets in the solar system

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