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Earth Communications

Satellite Captures Rare Images of Atmospheric Gravity Waves (cnn.com) 45

Posted by BeauHD from the rarely-seen-natural-phenomenon dept.
Earlier this week, Australian weather forecast service Weatherzone captured satellite images of atmospheric gravity waves pulsing through clouds over the ocean. CNN reports: The images show the waves spreading out from the coast of Western Australia, sending ripples through clouds over the Indian Ocean. The gravity waves were triggered by thunderstorms, with cold air flowing out from the squalls resulting in a disturbance in the atmosphere.

"The atmosphere is a big body of gas that acts like a fluid," said Ben Domensino, a meteorologist at Weatherzone. "It is exactly the mechanism as when a rock is thrown into the water, then the wave travels out from that source." The invisible waves are quite common in the atmosphere, he added. They are typically invisible unless they cause motion in clouds that can be detected by satellites. "Thunderstorms, air flowing over mountains and contrasting wind directions -- when you've got wind from two directions interacting with each other -- can also cause gravity waves," Domensino said.
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Satellite Captures Rare Images of Atmospheric Gravity Waves More

Satellite Captures Rare Images of Atmospheric Gravity Waves

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  • "Gravity Waves" -- what does this term mean?
    • Oh, should have searched. https://en.m.wikipedia.org/wik... [wikipedia.org]

    • Not what they think it means.
      This has exactly nothing to do with the generally discussed gravity waves, which for a start travel at the speed of light.

      Its just some rather large pressure waves that happened to be quite persistent, as they say 'like waves on a pond'.

      • Re:Not Gravity Waves (Score:5, Informative)

        by Barny ( 103770 ) on Saturday October 26, 2019 @03:13AM (#59349518) Journal

        You're confusing gravitational waves with gravity waves. The latter (as correctly used in the article) are waves caused in a fluid.

        • You are quite confused yourself.

          What you describe, is just called ... *waves*!

          Waves in a fluid. Like the ocean. Or air.

          Nothing to do with gravity at all.
          It's all *electromagnetic* collisions.

          Waves in the force of gravity are the only thing with the "g" word in it. And they deform spacetime and travel at light speed.

          • Re:There is no such thing. (Score:5, Informative)

            by eggstasy ( 458692 ) on Saturday October 26, 2019 @03:36AM (#59349534) Journal

            The term "specific gravity" is another name for "density". A gravity wave is a mechanical wave that propagates through compression and tension, where parts of a fluid increase their "specific gravity", i.e. through compression they momentarily gain a higher density.
            https://en.wikipedia.org/wiki/... [wikipedia.org]

            • Thanks.

              Now I have to go around remembering to differentiate between gravity and gravitational for random instances.

            • Sure, specific gravity is a term related to density.

              However these are in NO WAY gravity waves, unless you also refer to sound as gravity waves, and in fact, you know, waves (in water) as gravity waves.

              These are simple compression waves, propagating at approximately the speed of sound (as they should).
              There is no need to use a term which is simply not applicable to make them seem more 'special'.

              This is of course quite different from normal wind, which is a mass flow rather than a compression wave.

              Or perhaps

              • Remembe the old "MASCON" term from the space age? A concentration of mass produces a gravitational anomaly.
                If you measure the gravitational attraction of the ocean with a sufficiently sensitive instrument, the peaks of the waves will have more gravity than the troughs and you will be able to detect a minute difference in gravity when a wave passes beneath your instrument.
                Density implies gravity.

              • Sure, specific gravity is a term related to density.

                However these are in NO WAY gravity waves, unless you also refer to sound as gravity waves, and in fact, you know, waves (in water) as gravity waves.

                You mean waves in water which *are* referred to as gravity waves in fluid dynamics? https://en.wikipedia.org/wiki/... [wikipedia.org]

                When you correct people it helps to actually know what you're talking about. You sir do not.

        • Parent is right.

          While many may refer to these as "gravity waves", that is a misnomer. They are pressure waves.

          Gravity waves (and no, "gravitational" is not different from gravity) travel at the speed of light.

    • Oh, by gravity waves they mean waves.

      I remember a geology waves mini-course where the prof explained two surfaces moving against each other add energy to micro disruptions, building a wave and increasing its size. This also occurs on tar at stop signs as cars decelerating and accelerating slowly push the tar into waves, literally slow-mo waves.

      Indeed, the existence of the tar phenomenon shows the concept of gravity driving it is wrong, except tangentially in that it provides the force downward. It's the d

  • "Thunderstorms, air flowing over mountains and contrasting wind directions -- when you've got wind from two directions interacting with each other -- can also cause gravity waves,"

    How is this a gravity wave? Sound and looks like normal wind driven turbulence to me.

    • Re: (Score:2)

      by GuB-42 ( 2483988 )

      Wind turbulence is the cause, gravity waves are the effect.
      It is just like when you throw a rock in a pound. First it makes a splash, then, you have waves that ripple outwards. These are also gravity waves by the way.

      The difference between turbulence and gravity waves is well known by glider pilots. Turbulence is rough and common near mountains, waves are smooth and further away. Both are used by pilots to gain altitude.

  • This is proof we live in a multi-verse, for sure. And now I'm hiding. https://www.youtube.com/watch?... [youtube.com]
  • Zero-Gravity Raves [storm-djs.com] -- which is, apparently, a thing.
  • ..is what these are called.

  • Gravity Waves vs. Gravitational Waves (Score:5, Informative)

    by Wizzu ( 30521 ) on Saturday October 26, 2019 @07:01AM (#59349752)

    The difference between the terms of Gravity Waves vs. Gravitational Waves seemed confusing at least to me, so here's an article.
    https://medium.com/@GatotSoeda... [medium.com]

    "Gravitational waves are waves that vibrate through spacetime itself, as a result of gravitational forces as Einstein predicts in 1916. Gravitational waves are ripples in spacetime in accordance with Einstein’s theory of gravity.

    Gravity waves are waves driven by gravitational force. Gravity waves are waves in the Earth and atmosphere in accordance with Newton’s theory of gravity."

  • Wow (Score:2)

    by Dunbal ( 464142 ) *
    That's funny, I thought they were supposed to move at the speed of light or something.
  • I am a meteorologist, these are not uncommon, we see them quite often on satellite. Get a stable layer of air above a cloud layer and you see them.
    More click bait headlines.

  • The gravity waves were triggered by thunderstorms, with cold air flowing out from the squalls resulting in a disturbance in the atmosphere.

    Seriously, this sounds like accoustic shockwaves, not """gravity waves""".

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