Can the solar system act like a huge sucking fan?

[dougettinger]

I have asked this question in different ways before, but it has been either circumvented or avoided. I only want the straight truth. Can our 80 astronomical unit wide solar system with its various gravity fields within the invariable plane capture dust and gases of IMC's as it passes through them and also objects that range in size from comets to small planets ?

I know issues will arise immediately. 1) Planets and comets cannot be found in interstellar space and are generated in protostar disks. However, it has been made known that in the beginning of planetary formation, more than likely numerous newly formed planets were ejected from each new star system. 2) There are not enough ejected celestial bodies in interstellar space to make a difference. The chances of intersecting their paths is very improbable. However improbable, let's just set aside this issue and assume that their is a chance intersection of paths. 3) The velocity and vector differences of their trajectories with the Sun would be so different that these bodies would merely pass by with their paths becoming slightly hyperbolic. However, let's assume that the dust and gases and the interstellar bodies are traveling roughly parallel and roughly at the same velocity (a little less) as the Sun, 220 km/s, as they possibly should do being in the galaxy's plane.

The question remains after hopefully setting aside these issues - can the solar system perform like a huge sucking fan gathering material similar to fan blades collecting dust ?

Doug Ettinger
Pittsburgh, PA

[Chris Peterson]

I have asked this question in different ways before, but it has been either circumvented or avoided. I only want the straight truth. Can our 80 astronomical unit wide solar system with its various gravity fields within the invariable plane capture dust and gases of IMC's as it passes through them and also objects that range in size from comets to small planets?

In general, no.That's true not just for our solar system, but for all astronomical objects, of any mass. The only objects the Sun can capture are those which are matched in velocity to a few meters per second or less. Solar escape velocity falls off quickly with distance; the actual diameter of space where the Sun might reasonably capture particles is measured in solar diameters, not astronomical units. That represents a small volume of interstellar space.

Interstellar dust exists, of course, and passes through the Solar System. It has been found inside meteorites, trapped since the formation of the Solar System, it is recorded striking the dust sensors of many interplanetary space probes, and has been recovered during sample return missions. In all cases, it represents only a tiny fraction of the total dust, most of which is produced within the Solar System.

[dougettinger]

Your reply is excellent. It answers so well what I did not know, such as the solar escape velocity falling off quickly after several solar diameters. Thank you.

Doug Ettinger
Pittsburgh, PA

[dougettinger]

I have asked this question in different ways before, but it has been either circumvented or avoided. I only want the straight truth. Can our 80 astronomical unit wide solar system with its various gravity fields within the invariable plane capture dust and gases of IMC's as it passes through them and also objects that range in size from comets to small planets?

In general, no.That's true not just for our solar system, but for all astronomical objects, of any mass. The only objects the Sun can capture are those which are matched in velocity to a few meters per second or less. Solar escape velocity falls off quickly with distance; the actual diameter of space where the Sun might reasonably capture particles is measured in solar diameters, not astronomical units. That represents a small volume of interstellar space.

Interstellar dust exists, of course, and passes through the Solar System. It has been found inside meteorites, trapped since the formation of the Solar System, it is recorded striking the dust sensors of many interplanetary space probes, and has been recovered during sample return missions. In all cases, it represents only a tiny fraction of the total dust, most of which is produced within the Solar System.

I am still fussing about the possibilities of the capture of celestial objects (KBO's, larger planets, and comets) from interstellar space by our solar system. You mentioned the very limiting factor of the solar escape velocity falling off quickly with distance making the projected face for capture very small. Also, the velocities would have to match within a few meter per second.

I reviewed escape velocities in Wikipedia and found them for the Sun's gravity to range from 18.5 to 7.7 km/s which is a small but still sizable fraction of the solar system's overall speed of about 250 km/s thereby enlarging the space for capture from just several solar radii to 40 AU's on radius. And consider that interstellar space may be more crowded with spherical orbs more than we realize. The escape velocity is independent of the mass of the object trying to pass by and escape. And with the appropriate incoming trajectories chosen capture is very possible. Perhaps trajectories that are more tangential than parallel would make better candidates for capture (?) There are also the radiative pressure of the solar wind and the perturbing gravity forces of Kuiper Belt objects and the outer planets to consider in slowing down the incoming materials for converging them onto the Sun's trajectory path.

Is any of this reasoning at all justified ?

Doug Ettinger
Pittsburgh, PA

[Chris Peterson]

I reviewed escape velocities in Wikipedia and found them for the Sun's gravity to range from 18.5 to 7.7 km/s which is a small but still sizable fraction of the solar system's overall speed of about 250 km/s thereby enlarging the space for capture from just several solar radii to 40 AU's on radius. And consider that interstellar space may be more crowded with spherical orbs more than we realize.

There's no evidence that interstellar space is filled with debris, and there is no theoretical mechanism to explain such debris. The most distant solar system material we can reliably detect is in the scattered disc, out to about 100 AU. At that distance, solar escape velocity is 4 km/s. At the distance of the Oort cloud, the solar escape velocity is less than 0.5 km/s, and that's still only 10,000 AU. And that's still a very small distance. If there were enough material even in that range to explain bodies in the Solar System, we'd see scattering and absorption when we looked at distance stars. And statistically, the likelihood of encountering bodies at speeds so near our own is very small. All recorded interstellar dust particles have velocities much greater than solar escape velocity. Why would you expect the velocity of larger objects to be less?

Finally, there is still the problem that we have many samples of material from the Solar System, and nothing dates older than the formation of the planets. So either nothing is older, or the ratio of locally produced to imported material is very large, meaning that even if the latter exists, it isn't significant in terms of providing material for rings, moons, asteroids, etc.

There are also the radiative pressure of the solar wind and the perturbing gravity forces of Kuiper Belt objects and the outer planets to consider in slowing down the incoming materials for converging them onto the Sun's trajectory path.

I don't see how either can be a factor.