The sun has a sibling – but are they holding hands?

I guess the birth announcement got lost in the mail, which is understandable given the fact that it happened a few billion years ago, somewhat before the invention of e-mail or even a postal system. In case you haven’t heard: our Sun has a sibling! And it’s a girl!

She’s called HD 162826, which will give her some grief during grade school, but probably not as much as if she had been named Moon Unit Zappa, Elbow (3 children were given that name in 2009), Hotdog (2 in 2012), or Freak (34 in 1995). I don’t know how you determine the sex of a star, but apparently someone can, because everybody says HD 162826 is a sister. I’d love to send my congratulations to the parents, but their identity is somewhat vague.

In any case, the discovery of the Sun’s sister has triggered an outpouring of emotional responses and some typically wild speculations on the part of the press. The first article I saw on this was here, and this piece is interesting for a number of reasons. It gets off to a great start with this sentence:

“Researchers from the University of Texas at Austin has discovered that a previously known star may actually be the sibling of our own Sun.”

“Researchers… has discovered” is a little strange, but maybe that’s how they talk in Texas. All right, in the excitement it seems petty to quibble about the conjugation of verbs. The article continues:

“The possible solar system is located a mere 110 light years away from the solar system.”

This sentence is also intriguingly strange. First off, there’s nothing “mere” about “110 light years away,” at least if you’re using Google Maps to plan your trip. (I tried, and the closest hit is Hd’s Mesa, an employment agency on 1826 W. Broadway Road, Mesa, Arizona, a mere 9,100 km from my present location.)

A light year is 9.4605284 × 1015 meters. It would take the Voyager 1 spacecraft, which is traveling at a maximum rate of 62,136 km/h, at least 1,909,787,303,382.4 years to get there. That’s only if Voyager 1 is pointed exactly in the right direction, which I kind of doubt, and only if I’ve done the math right. If you find an error in my calculations, let me know.

Of course you have to take into account that 1,909,787,303,382.4 years is about 138 times longer than the current age of the universe (depending, of course, on the date at which you are reading this.) In 1.9 trillion years the universe will either still be expanding, or collapsing in on itself, depending on your feelings on the topic of dark matter. In the expanding universe scenario, some scientists calculate that the universe might double its size in 11.4 billion years. It’s unclear how things will go after that, but Voyager 1 will clearly need somewhat longer to arrive. If, on the other hand, you’re a proponent of universal contraction, everything will be closer together, so the trip won’t take quite as long. Maybe Voyager 1 should just park somewhere and wait.

But the intriguingly strange sentence above (“The possible solar system is located a mere 110 light years away from the solar system”) has more to offer. I suppose “the possible solar system” means that the sibling sun might also have a solar system, and “the solar system” at the end of the sentence presumably means “our solar system.” If I’m wrong, and these two phrases refer to the same solar system, I don’t quite understand how a thing can be 110 light years away from itself. Unless you are talking about some sort of weird, alternate reality. Of course, physicists like that kind of thing – remember Schrödinger’s cat, which demonstrates not only the possible existence of parallel universes, but also that Erwin Schrödinger had some serious issues with cats.

The idea that our planets might have long-lost siblings is old news. Earth’s first sibling was found in 2007, as you can read here. I’ve covered that story in an earlier article. A second sibling was found this year. The first candidate, Gliese 581c, is a mere 20 light years away, while Kepler 186f is 500 light years from us. That’s just how it goes: “children” (or planets, in this contorted world of familial metaphors) grow up, relocate to distant places, attend the university, and acquire huge amounts of debt before moving back home to live in the basement.

Both of these planets are “sisters.” It’s easier to tell the sex of a planet, I suppose; at least you can get closer and inspect them, without getting burned to a crisp.

* * * * *

In case you hadn’t noticed, I could go on talking about unusual grammar and interstellar sex determination all day. But the discovery of our “sister sun” has also prompted some scientific speculations that are worth considering. Consider this from the Tech Times article I cited above:

“Aside from being a potential sister star to the Sun, Ramirez and his colleagues also believe that there is a very small chance that the HD 162826 system could have planets suitable for life. While the chances may be small, the researchers are certain that the odds are not zero.”

I can’t resist one linguistic point here: the first sentence implies that the potential sister star is Ramirez and his colleagues. This is a common grammatical mistake called a “dangling participle.” The problem becomes clear if you consider a sentence such as, “Hanging from a tree, the firemen rescued a cat.” But more intriguing is the comment, “the researchers are certain that the odds are not zero.” It’s hard to find just about anything for which the odds are truly zero (rather than 0.0000000…00001); try it sometime and you’ll see.

Another article about the finding puts it this way:

“One of the most exciting consequences… is the likelihood that these stars support planets, and possibly even life. Back when the Sun’s siblings were all hanging out in their nursery together, there would have been a robust, inter-system exchange of planetary material and chemical runoff. Enriched chunks of early Earth could have been launched into other fledgling solar systems, seeding the potential for life on other planets.”

Now I don’t know how this passage strikes you, but there’s a point at which you have to be cautious about metaphors. There’s some serious hanky-panky going on in this nursery school. “Exchange of planetary material and chemical runoff” are clearly euphemistic references to some sort of bodily fluids. If you’re generous you might think the topic is spilling KoolAid, but then you get to the part about launching “enriched chunks of early Earth,” and it’s hard not to think about kids throwing around poop. Finally we get to “seeding the potential for life” – a figurative climax, if not a literal one. If by that point you haven’t figured out what the author is talking about… Let’s just say it’s not the kind of day care I’d consider for my kids.

Coming back to the science, one should remember that this nursery probably existed over 4 billion years ago, when things were pretty hot, and I’d say the limb that supports these speculations is a pretty long one. But some notable scientists – Berzelius, Kelvin, Hermann von Helmholtz, Francis Crick, and Stephen Hawking – have promoted this type of panspermia hypothesis, and I’m not one to argue with such bright bulbs.

This second piece from (clearly one of the first places you’d go to check out the latest findings from research) goes on to say:

“The idea that we might have genuine biological relatives on planets orbiting distant solar siblings is certainly tantalizing.”

I don’t quite know what they mean by “genuine biological relatives,” unless they’re referring to Vulcans, or a long-lost cousin named Bob, but it’s safe to say that the idea is tantalizing. Most things are, to somebody.

I’d like to jump into the fray of wild speculations by suggesting that our Sun and its sibling might be holding hands. That happens sometimes, as shown by the recent birth of twins. On Mother’s Day, at that. What are the odds of that? Certainly not zero.

Published by


I am a science writer at the Max Delbrück Center for Molecular Medicine in Berlin, author of fiction and popular science books, an artist, and a professional musician who performs on the viola da gamba and Medieval and Renaissance stringed instruments. I edit manuscripts of all types and teach the full range of scientific communication skills. I am doing theoretical work in this subject - see for example

2 thoughts on “The sun has a sibling – but are they holding hands?”

  1. It common practice in astronomy to capitalize things that are ours. For example,

    Jupiter has dozens on moons but Earth only has 1 Moon.

    Voyager left the Solar System in search of other stars and solar systems.

    The Andromeda galaxy is 2.5 million light years from our Galaxy.

    And just in case,

    Edwin Hubble discovered the expansion on the Universe.

    1. Thanks Peter. Sometimes I forget… I suppose, however, that we won’t be capitalizing “siblings” although, presumably, they are “ours”… 🙂

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.