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Deep Impact on Comet Theory
AlexGP writes "Proponents of the Electric Universe theory have gone out on a limb ahead of Deep Impact. They're predicting it will show comets are just rocks and not dirty snowballs.
Controversially they assert comets are highly negatively-charged asteroids on eccentric orbits. As they travel further into the Sun's radial positive electric field, they discharge into space, expelling material at supersonic speed."
Space isn't a perfect vacuum. Sound waves and shocks can exist anywhere there's enough gas to act in an ordered, collective fashion, and on solar system scales that doesn't require a very high density.
The solar wind is supersonic--it travels faster than sound waves will travel in it (which is why there's a bow shock upstream of the Earth). In the case of a comet, as you quoted, it's expelling material, and sound waves can travel in that.
Somebody makes a crack like this every time a space fluids topic gets posted on slash.
(Incidentally, why the heck is this posted under "Science" instead of "It's Funny, Laugh"? These are absolute crackpots.)
From what little I know, the so-called "Electric Universe" theory (or theories) is a variant on Plasma Cosmology [wikipedia.org]. Plasma Cosmology is a fringe scientific theory that asserts that plasma physics should play a more prominent role in cosmology and that the electromagnetic force should be considered more important than gravity in the evolution of the universe. This idea apparently originated with Nobel Prize winner Hannes Alfvén.
Of course, even Nobel Prize winners make mistakes (or at least the one I know does :-) ). Plasma Cosmology is almost uniformly viewed as incorrect and irrelevant by physicists and astronomers. The reasons, as far as I can tell, are that standard cosmology has been quite successful in predicting things like the cosmic microwave background and elemental abundances, not to mention things like cosmological redshift. Plasma cosmology cannot reproduce these things without adding on a lot of convoluted features that rely on some unproven (and seemingly outlandish) new plasma physics that has never been seen on Earth. In short, Plasma Cosmology doesn't explain a lot observations correctly in a simple way. It hasn't proven itself useful, which in the end is the measure of a good scientific theory.
So the short answer is, "Yes, it's BS". Now cue the die hard supporters claiming there's some sort of conspiracy to cover-up their theory, which is pretty silly if you know how science really works.
"You call it a new way of thinking; I call it regression to ignorance!" -- Operation Ivy
Sort of like how Titan didnt answer whther there are really methane lakes currently on the surface or not.
It showed there aren't large methane seas, which was one theory.
And like how the Mars probes havent told us if there is/was life.
That wasn't the point of Spirit and Opportunity. That was the point of Beagle, unfortunately.
In fact whether there was water is still disputed.
Not really. The discovery of hematite by the Mars Rovers is pretty conclusive. Combine that with the satellite studies that have shown water combined with CO2 in the ice caps, and there is no real dispute at all.
We need to be sending better probes out there that can do some real science.
They are doing real science. Science doesn't provide yes/no answers. It is about gathering data and doing experiments. We are doing more of that now than ever.
Space probes havent advanced in decades.
Considering the amazing Spirit and Opportunity missions and the pictures coming back from Cassini/Huygens as compared with brief visits to the outer planets from Voyager, I find that an very odd statement.