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'Oumuamua could be a shard from a dead planet

116 points| egfx | 6 years ago |nationalgeographic.com | reply

58 comments

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[+] robocat|6 years ago|reply
Has National Geographic gone downhill since the media part became https://en.wikipedia.org/wiki/National_Geographic_Partners

This reads like “Disney” science: take some facts and spin them to be entertainment. I thought the same of this article where I thought the reporting was twisting facts to make a headline: https://www.nationalgeographic.com/science/2020/04/lost-your...

[+] astro123|6 years ago|reply
I read a lot of astronomy journalism that I think is absolutely awful (one of the main reasons I made this account was to point out garbage articles/comments). I actually think that this is pretty good.

It mostly follows the paper (here's what looks like an earlier version of this paper that is easily available [1]), doesn't engage in too much hyperbole, isn't publicizing something widely outside of the consensus.

Disclaimer that I don't work on planetary formation/dynamics so am not an expert on this, but still, pretty impressed.

[1] https://www.hou.usra.edu/meetings/apophis2020/pdf/2018.pdf

[+] arbitrage|6 years ago|reply
That's how National Geographic has been run for decades. Wrap up fluff journalism in a mystique of authority and strangeness to distract from the overall shallow nature of the writing.

Facile views wrapped up in easily digestible photo journalism essays, then never reviewing the topic again.

It's always been fluffy pap.

[+] choward|6 years ago|reply
Thanks for pointing out Disney owns most of it. I honestly had no idea I shouldn't be taking National Geographic seriously anymore.
[+] calibas|6 years ago|reply
Not surprising, seeing as how Disney just took over National Geographic...
[+] corysama|6 years ago|reply
I realize an iPhone 6+ is an old phone. But, this is a simple page with some simple text and simple images that is working so hard to track me that it is completely unreadable even though they really want me to read it.
[+] dustingetz|6 years ago|reply
they don’t actually care if you read it. they want the ads to paint
[+] nathell|6 years ago|reply
Nitpick: it's ʻOumuamua, not 'Oumuamua. The initial letter is the ʻokina (U+02BB), representing a glottal stop.

https://en.wikipedia.org/wiki/%CA%BBOkina

[+] lordgrenville|6 years ago|reply
There was a discussion the other day about whether it's bad when HN gets derailed from TFA by incredibly minor details. I'm in favour of the tangents, which can often be more interesting than the primary topic - as is the case (for me) with your comment. Thanks for sharing :)
[+] bustadjustme|6 years ago|reply
> The ʻokina has historically been represented in computer publications by the grave accent (`), the left single quotation mark (‘), or the apostrophe ('), especially when the correct typographical mark (ʻ) is not available.
[+] LatteLazy|6 years ago|reply
Could be, could be something else, let's speculate widely!
[+] bufferoverflow|6 years ago|reply
It "could be" almost anything. Billions of years, hundreds of billions of stars in our galaxy alone.
[+] fizixer|6 years ago|reply
I don't see how this is a new discovery. That line of thinking was pretty much the implicit null hypothesis.

The question at that time was, is it something more than that? and that's what made it interesting.

[+] goodcanadian|6 years ago|reply
We didn't know how to make shards in the presumed shape of `Oumuamua, naturally. There is now a plausible model of planets being ripped apart by tidal forces which can result in such shapes.
[+] aaron695|6 years ago|reply
I'd still like a good take down of why this couldn't be from our solar system.

Seems highly unlikely these crazy 'from outside the solar system' ideas are likely.

This meme spreads well, but that to me means there is far more chance it is not true. The fact no one questions it also seems suspicious.

[+] btilly|6 years ago|reply
Seems highly unlikely these crazy 'from outside the solar system' ideas are likely.

This meme spreads well, but that to me means there is far more chance it is not true. The fact no one questions it also seems suspicious.

This left about 24 km/s faster than anything can go and remain inside of the Solar System. Do you have any idea how much energy it takes to get something going that fast?

A baseball going that fast has about 42 megajoules of kinetic energy. A semi on the interstate has about half a megajoule of kinetic energy. This thing was at least 100 meters long and all of it was going that fast.

For the record we do not have the technology to fire a rocket that fast. We only managed to get rockets to leave the Solar System by loading them up with gravity assists from planets. And even so they didn't get to that speed. If two asteroids have a head on collision, the pieces won't move that fast. (And it would have to be a heck of a collision to make a piece that big.)

If this came from inside of the Solar System, WTF accelerated it, how did it do so without breaking the object into smithereens, and why didn't we see evidence of the event that caused it?

By contrast this was going just about the average speed of interstellar objects in our neighborhood. (The Sun happens to be just passing through the ecliptic, and spends most of its time well above or below the Milky Way. Therefore to us, everything in our neighborhood is moving fast.) Any junk hanging around would have a trajectory that looks like this one. Now obviously space is pretty empty. Which is why it is so impressive that we actually spotted something from space.

Yes. It is highly unlikely that anything we see in the Solar System didn't come from here. But it is effectively impossible for anything starting in the outer reaches of the Solar System to get to this speed. And extremely likely that an interstellar object would go about this fast. Therefore it probably is an interstellar object.

[+] astro123|6 years ago|reply
The argument is actually really really simple. If it started from within the solar system, it would not (barring some three body interaction) have enough energy to escape. But, we know from observations that it does have enough kinetic energy to escape. There are two options,

1. It may have stolen some energy from another object (an accidental gravity assist), but we know that it didn't come close enough to anything big on its way though.

2. It came from outside the solar system and so entered with some velocity, and therefore will leave with roughly the same velocity it came in with.

We have well known mechanisms to eject objects from star systems so it isn't crazy to have things passing through. No-one questions it because high school level physics is enough to show why it is the only reasonable explanation.