A close pass by a red dwarf star, and a note on interplanetary and interstellar distances

First, in case you haven’t heard: 70,000 Years Ago, Another Star Flew by the Edge of the Solar System | RealClearScience.

According to an international team of astronomers, about 70,000 years ago a red dwarf star — nicknamed “Scholz’s star” for the astronomer who discovered it — passed by our solar system just 0.8 light years distant. In fact, 98% of the 10,000 simulations the team ran projected that the star’s path grazed the outer edges of the Oort Cloud, a region of space filled with icy planetesimals which marks the final boundary of our solar system.

…Scholz’s star is now twenty light years away and won’t be returning anytime soon. However, Dr. Coryn Bailer-Jones of the Max Planck Institute for Astronomy calculates that we may receive another visitor in the distant future. Last December, Baller-Jones reported that the rogue star HIP 85605 may pass as close as .132 light years to the solar system between 240,000 and 470,000 years from now. That’s a close miss on the cosmic scale, but more than far enough that our futuristic ancestors will have little to worry about. The only concern would be that HIP 85605’s foray through the inner Oort Cloud might send a few comets careening in Earth’s direction.

This is interesting and just goes to show that, on a large enough time scale, assuming we don’t drive ourselves extinct, humanity will eventually be able to go to the stars, even if we have to wait for other stars to occasionally come near us.  (Not that we could make such a trip with current technology, but it’s a lot easier than reaching the nearest current star.)

That said, it’s important to keep in mind what “near” means in this context since some news outlets are saying the star passed “within” our solar system, implying to most people that it passed near the planets or something.  As Pomeroy notes, this pass was 0.8 light years away.  While it’s less than a fifth the distance to the current nearest star (Proxima Centauri), that’s still over seven trillion kilometers, over 52,000 times the distance between the Earth and the Sun, or more than 1300 times the distance to Pluto.  Even the star HIP 85605 mentioned above that might some day pass as close as 0.132 light years away will still be more than 200 times the distance of Pluto.

Saying that these near passes are within our solar system is only accurate if your consider the solar system to encompass the theoretical Oort Cloud, thought to be a cloud of icy rocks that extends as far as 2 light years away, or half the distance to the next nearest star.  While some might argue that the phrase is accurate, it’s a far broader meaning of “solar system” than most people are familiar with.

It also illustrates that, as large as the solar system is, and it is incomprehensibly large by any human scales, it’s essentially the outer layers of the Sun when seen from interstellar distances.

Space is big. Really big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.

Douglas Adams, The Hitchhiker’s Guide to the Galaxy


18 thoughts on “A close pass by a red dwarf star, and a note on interplanetary and interstellar distances

  1. Sorta almost like a real-life version of Robert Forward’s Dragon’s Egg! (If you’ve not read it, I recommend it highly. Forward, in general, I highly recommend. He’s a physicist turned SF author.)

    I remember the big deal about the Voyagers “leaving” the solar system. From one perspective, I guess so, but in reality they’d just left the “city” for the “burbs”.


    1. Thanks. I think we talked about Forward on your blog, notably in relation to Rocheworld. I haven’t read Dragon’s Egg yet, but maybe someday I’ll get to it.

      For Voyager, they defined leaving the solar system as moving beyond the influence of the solar wind. It’s an interesting definition, and a meaningful milestone, but calling it “leaving the solar system” or “entering interstellar space” always had the feel of something the public relations people at NASA came up with. It passed the orbit of Pluto decades ago. It’s past the furthest known Kuiper Belt object, and probably substantially past the scattered disk. So I think they felt the heliopause was the last boundary they’d be able to make a big deal about.

      Liked by 1 person

      1. Aw, nuts. It’s been canceled. A cloudy day here in Tucson. 😦 On the other hand, I don’t think I would have been up for it anyways. We were already making plans for a friend to go with my husband just in case.


        1. Hopefully the new MRI will find something. I don’t envy you having to spend more time sitting still in that tube. Good luck!

          My shoulder lost some ground this week. The second opinion appointment got moved back to Wednesday after I changed doctors. I’m now resigned that, whatever the recommendation, this will be a long recovery.


          1. Don’t you just hate the waiting? URGH! I totally feel for you. I don’t deal with pain too well myself. I hope you are able to manage it.

            Well I just got a call a few minutes ago from my PCP who said that I don’t have Lyme disease. I’m actually disappointed. I never thought I would WANT to have that, but at this point it would be good to just be able to take some pills and be done with it.

            I don’t even know what they’re looking for with the next MRI. It’s of the cervical spine. I know that the vestibulospinal tract runs through there, and those nerves control balance. The VEMP test showed an abnormality that could indicate a problem with specifically with the vestibulospinal tract (or MS, which has been ruled out). That’s all I know.

            Well I’m curious to know how it goes on Wed. with the second opinion. Good luck to you too!


          2. I do hate waiting, although that appears to be the way of medicine these days. Oh well, at least we live in times where medicine has at least some effectiveness. (I read something yesterday that said that prior to the 20th century, sick people statistically had a better chance of recovering if they stayed away from doctors.)

            It would drive me crazy if they told me to report for an MRI and wouldn’t tell me why. Assuming you’re comfortable sharing, I curious too to know if they find anything.

            I’m grateful for your interest. I think being able to communicate with someone else who’s also going through a medical issue has been therapeutic, at least for me. Thank you!

            Best of luck and talk with you soon.

            Liked by 1 person

          3. And to think someday people will be looking back at us and thinking, “I sure am glad I didn’t have to rely on that ancient technology. Geez, they couldn’t even cure cancer.” (Well, let’s hope that’s what they say.)

            My last year of college I had lasik eye surgery. That felt like a miracle, even though now it’s pretty common. I went from 20/400 to 20/15 in a matter of minutes! I still remember the moment they put the corneal flap back on and I could see instantly.

            This has been therapeutic for me too! I feel like I’m being boring when I talk about these things, so I try not to unless someone asks, and then I keep the details to myself. Health talk is fairly boring when you’re healthy. So fellow sufferers unite!

            Plus, I’ve had a few friends suggest it might be psychological. Of course, there’s nothing I can say to that without being self-defeating or sounding defensive, so I tend to shut down and avoid the topic.

            I will let you know how the MRI turns out. We’ll keep each other informed!

            Liked by 1 person

          4. I’ve had someone make something similar to the psychological comment to me: “Oh yeah, I pulled a tendon once. I just waited and it got better.” (As if I’ve never pulled a muscle or tendon before myself.)

            The implication of these comments is that the pain isn’t real or that we’re just being overly sensitive. It’s basically a dismissal of someone else’s suffering. Since all suffering is ultimately subjective, you’re right, there’s no good response. Except perhaps to remember not to do it to others in the future.


          5. Very good point! I haven’t really had health problems before this, so now I’m wondering if I’ve said anything similar in the past. I probably have. Well one good thing has come out of all this—it’s definitely been a learning experience. I’ve been thinking of it as a lesson in patience, but now you’ve shown me it’s empathy too. That’s definitely a weak area for me!


          6. We’ve only been interacting for a few months, but I would definitely not describe you as lacking in the empathy department. But I agree that these kinds of experiences enhance our sense of empathy and sympathy.

            Although it occasionally occurs to me that someone’s suffering might be psychological, I’ve always felt like the evidence would have to be pretty strong before I’d burden them with such a suggestion, since there are few things as dispiriting as being told that, “it’s all in your head.”

            Liked by 1 person

          7. Thanks! Well, I’m much nicer online. I have a little more time to think about what I say. No promises, though. 🙂

            I’m telling you, this whole psychological thing is starting to get on my nerves. Just about everyone has mentioned it, including my husband. I’ve actually brought it up with both my PCP and the neurologist, just to be totally forthcoming about the problem. (Objectively speaking, you could say I’ve been dealing with stress relating to my mother’s illness, so I can’t dismiss that as a possibility, even though it all feels wrong to me.) Both doctors dismissed the psychological aspect. The PCP asked, “Do you feel depressed?” I said “No, I’m quite happy, except this dizziness.” That was the end of the conversation. Then the other day I asked him “why no one can find anything” and he reminded me that they did find something—that delayed latency on the VEMP test. So there’s is evidence of a non-psychological problem! YAY!

            Liked by 1 person

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