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Sand in space
If I were launched into space and was able to achieve an independent orbit
far away from the earth's gravitational field, and released some grains of sand, would the solar wind blow them away? |
#2
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Sand in space
On 06/04/2011 10:55 AM, Litus Arare wrote:
If I were launched into space and was able to achieve an independent orbit far away from the earth's gravitational field, and released some grains of sand, would the solar wind blow them away? No, not enough surface area. More likely that the grains of sand would actually start coming together under their own mutual self-gravitation. In fact that's how the Solar System first formed, dust and gas fell together. Yousuf Khan |
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Sand in space
Litus Arare wrote:
If I were launched into space and was able to achieve an independent orbit far away from the earth's gravitational field, and released some grains of sand, would the solar wind blow them away? This depends on their size. Actual sand (as in beach sand) would be too heavy and the main effect would be the "Poynting-Robertson Effect" which is essentially due to solar radiation pressure being slightly aberrated (appearing to be from slightly in front of a radial line to the Sun), so these grains would stay in orbit but slowly spiral into the Sun (or to the distance at which they would vaporise). Sand-sized particles would stay in orbit for a long time; smaller particles would spiral in more rapidly. Very small particles, such as comet tail dust and (perhaps) cigarette smoke, would indeed be blown out by radiation pressure. The "break-point" where the two effects balance is around size 0.5 micrometre, depending on properties. -- Mike Dworetsky (Remove pants sp*mbl*ck to reply) |
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Sand in space
On Jun 4, 7:55*am, "Litus Arare" wrote:
If I were launched into space and was able to achieve an independent orbit far away from the earth's gravitational field, and released some grains of sand, would the solar wind blow them away? Do carbon buckyballs count as sand? Perhaps little bits of atomic carbon could be expected to move along with the solar wind, such as the tonnes of helium that's blown away from Earth and is extracted from our gravity pool by the solar wind. http://translate.google.com/# Brad Guth, Brad_Guth, Brad.Guth, BradGuth, BG / “Guth Usenet” |
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Sand in space
In sci.astro message , Sat, 4 Jun 2011
11:19:22, Yousuf Khan posted: On 06/04/2011 10:55 AM, Litus Arare wrote: If I were launched into space and was able to achieve an independent orbit far away from the earth's gravitational field, and released some grains of sand, would the solar wind blow them away? No, not enough surface area. More likely that the grains of sand would actually start coming together under their own mutual self-gravitation. In fact that's how the Solar System first formed, dust and gas fell together. The solar wind is irrelevant. According to Wikipedia, the Solar Wind amounts to 6.7 billion tons per hour - about 2 million tons per second - at a speed of 400-750 km/s. But the Sun emits 4 million tons of photons per second, at 300,000 km/s. The light therefore has about a thousand times as much momentum as the wind. At Earth's distance, not orbiting, the light pressure will balance a sail of 1.6 gm / sq m, equivalent to ordinary paper 2 um thick. Grains in circular orbit will apparently not feel the Sun's gravity, and can be pushed out into an elliptical orbit. Since the solar pushes on the grains will be virtually parallel, the minute gravitational force might, eventually, cause clumping. More likely, you will get something like a junior version of the meteor trails left by comets. -- (c) John Stockton, near London. Web http://www.merlyn.demon.co.uk/ - FAQish topics, acronyms, and links. Correct = 4-line sig. separator as above, a line precisely "-- " (RFC5536/7) Do not Mail News to me. Before a reply, quote with "" or " " (RFC5536/7) |
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Sand in space
Mike Dworetsky wrote:
Litus Arare wrote: If I were launched into space and was able to achieve an independent orbit far away from the earth's gravitational field, and released some grains of sand, would the solar wind blow them away? This depends on their size. Actual sand (as in beach sand) would be too heavy and the main effect would be the "Poynting-Robertson Effect" which is essentially due to solar radiation pressure being slightly aberrated (appearing to be from slightly in front of a radial line to the Sun), so these grains would stay in orbit but slowly spiral into the Sun (or to the distance at which they would vaporise). Sand-sized particles would stay in orbit for a long time; smaller particles would spiral in more rapidly. Very small particles, such as comet tail dust and (perhaps) cigarette smoke, would indeed be blown out by radiation pressure. The "break-point" where the two effects balance is around size 0.5 micrometre, depending on properties. The original question was about the effects of the solar wind (not about radiation pressure). The best way to see this question as a natural experiment is to examine comet tails. The dust tail of a comet is driven by the solar radiation pressure. They look amorphous and reflect sunlight (they have the same spectrum as the Sun). Gas tails are driven by the solar wind, and inhomogeneities and irregular emissions from the cometary body cause the gas tails to develop clumps and structure, and occasionally you can see disconnection events as clouds of atoms from the comet are pinched off and blown away. So the solar wind does not affect the movement of sand grains (not much, anyways). -- Mike Dworetsky (Remove pants sp*mbl*ck to reply) |
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Sand in space
On Jun 5, 11:50*pm, "Mike Dworetsky"
wrote: Mike Dworetsky wrote: Litus Arare wrote: If I were launched into space and was able to achieve an independent orbit far away from the earth's gravitational field, and released some grains of sand, would the solar wind blow them away? This depends on their size. *Actual sand (as in beach sand) would be too heavy and the main effect would be the "Poynting-Robertson Effect" which is essentially due to solar radiation pressure being slightly aberrated (appearing to be from slightly in front of a radial line to the Sun), so these grains would stay in orbit but slowly spiral into the Sun (or to the distance at which they would vaporise). *Sand-sized particles would stay in orbit for a long time; smaller particles would spiral in more rapidly. Very small particles, such as comet tail dust and (perhaps) cigarette smoke, would indeed be blown out by radiation pressure. *The "break-point" where the two effects balance is around size 0.5 micrometre, depending on properties. The original question was about the effects of the solar wind (not about radiation pressure). *The best way to see this question as a natural experiment is to examine comet tails. *The dust tail of a comet is driven by the solar radiation pressure. *They look amorphous and reflect sunlight (they have the same spectrum as the Sun). *Gas tails are driven by the solar wind, and inhomogeneities and irregular emissions from the cometary body cause the gas tails to develop clumps and structure, and occasionally you can see disconnection events as clouds of atoms from the comet are pinched off and blown away. So the solar wind does not affect the movement of sand grains (not much, anyways). -- Mike Dworetsky (Remove pants sp*mbl*ck to reply) How about the solar wind moving those icy carbon buckyballs, a C60 (Buckminsterfullerene) of 1 nm diameter, that's only worth as little as 1.205e-24 kg each (plus whatever else they might contain, such as h2o or 4He)? http://translate.google.com/# Brad Guth, Brad_Guth, Brad.Guth, BradGuth, BG / “Guth Usenet” |
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