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Large stationary gravity wave in the atmosphere of Venus
- bahro 10y agoTo be clear, this article is about gravity waves (https://en.wikipedia.org/wiki/Gravity_wave https://en.wikipedia.org/wiki/Gravity_wave), or ripples at the interface of two media of different densities caused by gravity, such as waves on the ocean or ridges of clouds, not gravitational waves (https://en.wikipedia.org/wiki/Gravitational_wave https://en.wikipedia.org/wiki/Gravitational_wave), the propagating ripples in spacetime.
- Insanity 10y agoImportant distinction, +1 for linking to the wikipedia articles!
- maxxxxx 10y agoWith the LIGO discoveries last year I thought about gravitational waves too. Having such a wave having effects visible with the naked eye would be huge. It would probably rip the planet apart.
- greglindahl 10y agoGravity waves aren't caused by gravity, they are in the direction of the gravitational force.
- OscarCunningham 10y agoSure they are. Some of the denser fluid is above the average level of the surface, and gravity pulls it back down again. That's what makes the wave.
- greglindahl 10y agoGravity is one of several forces that may act on what's going on, but the cause of the wave is the initial perturbation, which isn't gravity. Put another way, if I have a steady-state hydrostatic system, gravity waves won't just spring into existence. You need that initial push. In this case, the initial push seems to be wind hitting a mountain and being forced up.
- contravariant 10y agoYou need the medium, gravity, and 'push' to get a wave. Calling them <medium>-wave, or 'push'-wave doesn't really tell you anything useful, so they're called gravity-waves. An alternative would have been buoyancy-wave, but apparently this didn't catch on (buoyancy and gravity are really two sides of the same coin, anyway).
- Godel_unicode 10y agoBuoyancy is related to density, which is independent of gravity. Check: buoyancy can exist in a non-inertial reference frame provided acceleration in a "downward" direction. Also, you don't need gravity to be the force being acted against in order to form a wave. You can get impact waves in water at 0g because of surface tension. https://en.m.wikipedia.org/wiki/Buoyancy https://en.m.wikipedia.org/wiki/Buoyancy
- deleted 10y ago[deleted]
- simonh 10y ago> gravity waves won't just spring into existence. You need that initial push. The gravity wave that causes tides on Earth requires no such push, it's just straight up deformation of the oceans by Lunar and Solar gravity. > In this case, the initial push seems to be wind hitting a mountain and being forced up. Where did you get that from, the body of the article? It's not in the abstract, which only talks about gravitational effects.
- em3rgent0rdr 10y agoConfusing terminology. I say the scientific community should rename "gravity" waves to "buoyancy" waves, which is more specific and accurate.
- andy_ppp 10y agoHere is a picture (I think) of this phenomena; it's much larger than I thought!
- autocorr 10y agoIt's really something that Akatsuki is doing amazing science after the trials and tribulations that satellite has been through. After failing orbital insertion around Venus, it went five years in heliocentric orbit to reposition itself for insertion around Venus again. The team ended up macguyvering its secondary attitude control jets[1] for a long burn (~20 min) that they weren't designed for, but it worked and allowed for a successful insertion--albeit in a non-ideal orbit with a 9 day period instead of the originally planned 1.25 days. [1] https://spaceflightnow.com/2015/12/06/japanese-space-probe-to-steer-into-orbit-around-venus/ https://spaceflightnow.com/2015/12/06/japanese-space-probe-t...
- LyalinDotCom 10y agoas someone who isn't a scientist I found this link to be a bit easier to consume: http://gizmodo.com/an-enormous-atmospheric-anomaly-has-been-spotted-on-ven-1791172483 http://gizmodo.com/an-enormous-atmospheric-anomaly-has-been-...
- WalterBright 10y ago> thick clouds of sulfuric acid Given how reactive sulfuric acid is, how does this concentration remain stable?
- Florin_Andrei 10y ago"Reactive" depends on the environment. E.g. sulfuric acid in a container made of glass does not do much and remains stable a long time.
- greglindahl 10y agoConsulting https://en.wikipedia.org/wiki/Atmosphere_of_Venus https://en.wikipedia.org/wiki/Atmosphere_of_Venus the atmosphere is mainly CO2 and molecular nitrogen, neither of which reacts with sulfuric acid. The clouds are at 10km and up, so they don't interact much with the surface, which has a tallest mountain peak of 11km.
- 56678tytyu 10y agoOxygen is one of the most corrosive gases. How do we remain stable? But reducing ourselves to ash...of Hydrogen.
- mirimir 10y agoHow? Lack of activation energy. And indeed, metabolism is basically catalyzed combustion.
- deleted 10y ago[deleted]
- CydeWeys 10y ago> The planet Venus is covered by thick clouds of sulfuric acid that move westwards because the entire upper atmosphere rotates much faster than the planet itself. How the hell?! I get that the length of a Venus day is really long (243 Earth days), but why would the wind be rotating in the same direction but faster?
- greglindahl 10y agoThat's one of the questions that's interesting... there's no obvious reason.
- JumpCrisscross 10y agoAnd they're speeding up! "Already travelling at super-hurricane speeds, winds on Venus...accelerated by an astonishing one-third" between 2006 and 2012 [1]. [1] http://www.abc.net.au/science/articles/2013/06/19/3784975.htm http://www.abc.net.au/science/articles/2013/06/19/3784975.ht...
- JumpCrisscross 10y agoFun fact: spiral galaxies' galactic arms are stationary waves. They don't spin like spokes on a wheel. Stars in the arms don't remain in them - every star traverses through the arms and the regions between them [1]. Indeed, correlations have been hypothesised between Earth's extinction events and our Sun's predicted passage through these arms [2]. [1] https://m.youtube.com/watch?v=c5Us-jonCLA https://m.youtube.com/watch?v=c5Us-jonCLA [2] https://arxiv.org/pdf/1309.4838.pdf https://arxiv.org/pdf/1309.4838.pdf