# What is the force of a CME on objects in space?

I've been reading a little bit about coronal mass ejections lately and they seem really interesting, and they cause a lot of amazing things to happen. However, one thing I haven't seen is the physical force they can have on objects. CMEs seem to have a lot of mass and they're moving at a high rate of speed so I imagine they must have some effect on objects in space, right? What kind of effect can they have on smaller objects like meteoroids, comets, or satellites (as far as orbit, rotation, anything else)?

This isn't a complete answer, but it's a partial one: http://pwg.gsfc.nasa.gov/istp/outreach/sunearthmiscons.html

Despite the electromagnetic havoc they play with satellite electronics and with Earth's magnetic field, the solar wind and CMEs barely exert a pressure or force that you could measure. In fact, they couldn't ruffle the hair on your head. The solar wind has fewer particles per cubic centimeter than the best vacuums scientists have ever created on Earth. Our own air is billions of times denser than the solar wind, such that a cubic centimeter of air has as many particles as a cube of solar wind measuring 10 kilometers on each side.

So, for your question on changing orbits - not very much. Granted everything moves a little under any pressure.

Now, the lighter the object is to it's surface area, the more a CME can move it, that's why a solar sail, very light weight and large area, might work. CMEs can also move gases, like the tail of a comet can be pushed visibly away from the sun (I read that, but misplaced the article), or lighter, high atmospheric gas can be blown away from smaller planets.

Also, no 2 CMEs are exactly alike. A smaller and/or a younger star will emit much stronger CMEs, so around a red dwarf for example, the effect might be more noticeable for tiny asteroids and the like.

A large CME will run 700km/sec at earth's distance from the sun. Proton flux can get up to 20 protons per cubic cm.

For a 1 square cm object facing the sun in earth orbit that amounts to being hit by a mass of 2.3e-18 kg traveling 700000 m/sec every second. That works out to a force of 0.000001127 Newtons per second. Not much push. (barring math errors of course, they love to creep in)