Jan 01 2008

Ulysses’ Measurement of the Solar Wind

Published by at 3:12 pm under Astrophysics

According to a Wikipedia article on Comet McNaught, NASA and ESA’s Ulysses spacecraft “made an unexpected pass through the tail of the comet”, where its Solar Wind Ion Composition Spectrometer (SWICS) “measured the composition speed of the comet tail and solar wind”.
The article explains that sensor data showed that oxygen ions in the solar wind had picked up electrons to replace some of their missing electrons as the ions passed through the tail of the comet.  It goes on to say that “the tail had slowed the solar wind to half its normal speed.”
Space science professor Michael Combi is quoted as saying:  “This was very surprising to me. Way past the orbit of Mars, the solar wind felt the disturbance of this little comet. It will be a serious challenge for us theoreticians and computer modellers to figure out the physics,” *
Here we learn that as atomic ions traveling radially outward from the sun in the solar wind pick up electrons and incorporate them into atomic orbitals, the ions slow down.  For anyone willing to learn some physics, this is because after the ions pick up electrons, they collect more gravitions.  The ions will slow down due to increased gravitational acceleration back toward the sun.
* http://en.wikipedia.org/wiki/Comet_McNaught

2 responses so far

2 Responses to “Ulysses’ Measurement of the Solar Wind”

  1. Carlon 02 Jan 2008 at 11:46 pm

    That was a “serious challenge” for your theory to explain the slowdown ;)

  2. Kevinon 03 Jan 2008 at 8:18 am

    The solar wind is an interesting phenomenon to study. Atoms, or pieces of atoms, that are stripped of all of their electrons, and ejected outward due to extreme temperatures and pressures, just keep going at their ejected velocities. They may even speed up some in the first few thousand miles due to all the radiation coming behind them.
    Much of the solar wind is traveling near 600 km/s, which is around one million miles per hour. If free nuclei were indeed pulled by gravity, just think how fast those particles would have to be traveling as they left the sun, – to be going 600 km/s yet as they encountered the Ulysses craft! The explanation of the matter is that nuclei, – that have no electrons left, are not pulled by gravity at all.
    With electrons in the solar wind we can surmise that some nuclei are able to capture electrons again near the sun. These ions will then at some point start to slow down, and may start to arc back toward the sun. By the time the solar wind passes planets such as Earth or Jupiter, particle density is greatly reduced, and capture of an electron by a positive ion would be a rare event.

Trackback URI | Comments RSS

Leave a Reply