back to article Astroboffins spy a rare exoplanet evaporating before their eyes

Somewhere in the Cancer constellation lies a mini-Neptune sized planet that is disappearing at rate faster than ever seen before, according to research published in Astronomy & Astrophysics on Thursday. The exoplanet, known as GJ3470b, is located about 97 light years away. It’s a rare find as most exoplanets are either big and …

  1. Fruit and Nutcase Silver badge

    Scientists estimate that GJ3470b is losing up to 10 billion grams of material every second

    What's that in sheep? I can't visualise 10 billion grams...

    1. VeganVegan
      Holmes

      The whole point of the metric system is to make large numbers more ‘palatable’.

      10 billion g (assuming billion is 9 zeros) = 10 million kg = 10,000 metric tons = 10 kilotons. </pédant>

      1. Pen-y-gors Silver badge

        Re: The whole point of the metric system is to make large numbers more ‘palatable’.

        Yep 10,000 tons a second - which the article implies is incredibly fast.

        BUT... the line before says

        For other types of exoplanets like hot Jupiters, which also orbit close to its host stars, the rate of evaporation can be as high as thousands of tons per second but the impact is much smaller.

        So, is 10,000 tonnes a second a little or a lot?

        It's very bad practice to mix units in an article.

        1. This post has been deleted by its author

        2. Stoneshop Silver badge
          Headmaster

          Re: The whole point of the metric system is to make large numbers more ‘palatable’.

          So, is 10,000 tonnes a second a little or a lot?

          Yes.

          For comparison, the Earth is about 6E21 tonnes, which at a rate of 10kton/sec would be gone in 6E17 seconds, 1.67E14 hours, 19E9 years. Slow enough to not bother me.

          1. John Brown (no body) Silver badge

            Re: The whole point of the metric system is to make large numbers more ‘palatable’.

            "For comparison, the Earth is about 6E21 tonnes, which at a rate of 10kton/sec would be gone in 6E17 seconds, 1.67E14 hours, 19E9 years. Slow enough to not bother me."

            Now do the same for the mass of the atmosphere, leaving the rocky bit out of it. Is it a bit more of a worry now? :-)

    2. Spherical Cow Bronze badge

      A sheep is approx 100kg so that's 100,000 sheep per second.

      There are approx 10 million sheep in Wales so that's 1% of Welsh sheep per second.

      All the sheep in Wales would be blown away in less than two minutes.

      1. Stoneshop Silver badge
        Boffin

        All the sheep in Wales would be blown away in less than two minutes.

        Yeah, but where are they ending up? Inquiring minds want to know.

        1. Crisp Silver badge

          Re: All the sheep in Wales would be blown away in less than two minutes.

          A sheep in a vacuum will continue on its trajectory unless acted upon by an outside mint force.

          1. Inventor of the Marmite Laser Silver badge
            Coffee/keyboard

            Re: Mint Force

            Keyboard meet coffee

      2. Sgt_Oddball Silver badge

        Wrong unit of mass..

        We have standards around here...

        It works out as 2380.9524 kilojubs per seconds... Which is a massive amount of jubs blown away into space I'm sure you'll all agree.

      3. Anonymous Coward
        Anonymous Coward

        "A sheep is approx 100kg"

        Given one goose and many geese, I've always assumed it should be one shoop and many sheep.

        Explains what Cher was singing about anyway.

      4. Robert Helpmann?? Silver badge
        Boffin

        Wales and Sheep inna Vacuum

        Wales is for area, not volume and why bring sheep into it at all? That's just wrong! In proper El Reg units of measure, that's about 2381 KiloJubs and in improper El Reg units of measure, 1149441 Adult Badgers, 11231 Great White Sharks, 6667 Skateboarding Rhinoceri or 222 Austrailian Trams, give or take.

        REF: https://www.theregister.co.uk/Design/page/reg-standards-converter.html

    3. Pascal Monett Silver badge

      I've got a different problem with that : who on Earth decided that is it a good idea to use the gram to express exoplanetary loss of mass ?

      We're talking about a planet that is light-years away, losing copious amounts of mass, and you deliberately choose the smallest unit of mass we have to express it ?

      Saying ten thousand tons of mass per second wasn't impressive enough ?

      1. disgustedoftunbridgewells Silver badge

        To me ten thousand tons per second sounds a hell of a lot more than a billion grams per second or whatever the article said.

        1. ArrZarr Silver badge

          It's weird, once you start getting silly numbers of zeroes involved, the actual unit starts getting less important, although 10 Gigagrams would probably be the most relevant SI-ish term...

          1. FrogsAndChips Silver badge

            @ArrZarr

            SI unit for mass is kilogram, so shouldn't that be 10 Mega kg, however weird that sounds?

          2. Yet Another Anonymous coward Silver badge

            They are Americans, they are catching onto the metric system gradually so one day will switch from cgs to mks.

            Astronomy is still very cgs, since the numbers are all so unimaginable an extra 3 in the exponent doesn't make a lot of difference and it's not like you can relate any of them to normal quantities.

      2. Anonymous Coward
        Anonymous Coward

        reason for grams is Kilogram turned out of by non-standard

        but grams are chemically still linked directly to mass and will do whilst they calibrate new "mass standard"

        1. JeffyPoooh Silver badge
          Pint

          Re: reason for grams is Kilogram turned out of by non-standard

          Kids these days probably think that there's 1024 grams per kilogram.

    4. Julian S

      about 1/3 of a Wales of sheep.

  2. IceC0ld Silver badge

    Sheep tend to range from 40 to 150 Kgs, so for the sake of easier maths we call it 100 Kgs

    100 x 10 = 1 Tonne

    and there are 10 000 Tonnes a second of mass to account for

    10 000 x 100

    we are looking at 1 MILLION sheep a second ..............

    </ abstract pédant>

    1. David 132 Silver badge
      Boffin

      100,000 sheep per shecond, shurely?

      10 sheep per ton

      10,000 tons a second

      = 100,000 sheep.

      Now if you’ll excuse me, all this sheep counting... Zzzzzzzz.....

      1. IceC0ld Silver badge

        NOT a million

        100,000 sheep per shecond, shurely?

        ah yes, my bad, but in my defence, I'm an idiot :o)

  3. redpawn Silver badge

    This should be an object lesson

    Evaporative cooling should be banned before it gets out of control and we lose our planet.

    1. Inventor of the Marmite Laser Silver badge

      Re: This should be an object lesson

      And ban vapourware

      1. RLWatkins

        Re: This should be an object lesson

        And vaporwave, while we're at it. Can't abide the genre.

  4. DJV Silver badge

    I fully expect GJ3470b to get the Weight Watchers Inspiring Achievement Award for 2019.

  5. Peter Ford

    That's no moon...

    It's a very early prototype of the Death Star: they just haven't quite got the power output up to production levels yet...

    1. Pedigree-Pete
      Black Helicopters

      Re: That's no moon...

      Hi Peter. I thought that. The large black disk looks awfully like a big communications dish. Run and hide. :)PP

      >I'm no astro boffin but I do know a moon/planet in transit when I see one.

  6. Anonymous Coward
    Anonymous Coward

    JWST

    "These planets are difficult to study as they can only be viewed via ultraviolet light. The researchers hope to continue observing GJ347b using Hubble and eventually the James Webb Telescope..."

    If they can only be observed via ultraviolet light then the James Webb Space Telescope won't be able to see them because its sensors will only operate in the Red to mid-infrared range and because it's going to be located at the Sun-Earth L2 point there won't be any possibility of adding a UV detection capability in the foreseeable future. Furthermore, I suspect that the gold-plated mirror is not suitable for UV observation.

  7. DropBear Silver badge

    Rather a lot of unanswered questions there

    So how exactly will the planet continue to evaporate once it lost all its atmosphere - is its sun going to start chipping away at rock then? Or is it a completely gaseous planet (in which case what exactly delimits its "atmosphere")...? And how can we even possibly know it's shrinking, considering that based on its expected billion-year lifespan and the history of our ability to detect exoplanets being measured in mere years it's hard to imagine we could possibly have detected any directly measurable change in its size...? Is this a theoretical inference only, based on the circumstances we expect the exoplanet to exist in...?

    1. FrogsAndChips Silver badge

      Re: unanswered questions, or unread article?

      In a few billion years left [sic], there may be nothing left except the rocky core of GJ3470b.

    2. Killfalcon Silver badge

      Re: Rather a lot of unanswered questions there

      Our current understanding of low density planets is that they're a *lot* of gas around a smallish rocky core, though at Jupiter-ish sizes there's likely some crazy pressure-related shit going on with metallic, liquid, hydrogen. This one isn't anywhere near to Jupiter scales so it's probably just rocks.

      So it's losing all the gas and as the article states it'll eventually end up with just the rocky core.

      1. DropBear Silver badge

        Re: Rather a lot of unanswered questions there

        Sorry but that excuse is objectively wrong. The article clearly says "in only a few billion years from now, half of the planet may be gone". Not the atmosphere. The planet. I continue to consider my question valid, and apparently eight people didn't read the article.

  8. VikiAi Silver badge
    Happy

    Oh, what a world! What a world!

    I'm melting! Melting!

  9. Flakk
    Joke

    Missed Opportunity

    If you'd suggested a mini-Uranus sized planet, the whole losing gas concept would have been much more entertaining.

    1. cookieMonster

      Re: Missed Opportunity

      You spelt hole wrong

    2. JeffyPoooh Silver badge
      Pint

      Re: Missed Opportunity

      Also missed, the "IT'S SHRINKING!!! IT'S SHRINKING!!!" meme (from the movie '2010 Odyssey').

      https://youtu.be/38EDhpxzn2g

  10. Palf

    Sounds like a good candidate for a prison planet.

  11. PyLETS

    Probably not enough of a magnetic field to protect it

    The earth's magnetic field provides protection against charged particles which would otherwise have a similar atmosphere-stripping effect on our planet.

    https://en.wikipedia.org/wiki/Earth%27s_magnetic_field

  12. cray74

    If you could bottle that...

    Several billion years to evaporate down to its rocky core? That's still faster than my diet.

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