just-me wrote:
Look at the science involved
Good idea.
The presenter keeps talking about a comet "twice the size of Jupiter". He never says whether he means twice the mass, or twice the diameter, or what. He talks about a sun flare pushing the comet away from the sun. I didn't see the push he claimed. Whether there would be a significant change in orbit would depend a lot on the density of the comet.
Later the guy shows a computer simulation (it's not clear to me whether he believes it's a video) where he measures the size of the comet by including the tail. But that's dust and gas blown off the comet by heating and solar wind. The density of the tail is so low that the space probe
Stardust could fly through a comet's tail at high speed. The actual solid cores of comets generally have diameters from 750m to 20km. The diameter of Jupiter is 143000km, so I would say Jupiter is larger.
Comets are usually described as dirty snowballs. Their densities are estimated to range from 0.1 to 2. So lets estimate the mass of a large (20km), dense (2) comet. The volume of a sphere is 4/3 * pi * r^3. If we measure r in metres we get a volume in cubic metres. We multiply the volume by 2 for the density to get the mass in tons. A 20km diameter means 10km = 10^4m radius. So the volume is 4/3 * pi * (10^4)^3 = 4.19 * 10^12 cubic metres. The mass would be 8.38 * 10^12 tons. Let's compare that to Earth, Mercury and Jupiter.
Mass of Earth: 6 * 10^21 tons. Roughly 1 billion (10^9) times as heavy as a large comet.
Mass of Mercury: 3.3 * 10^20 tons. Roughly 40 million times as heavy as a big comet.
Mass of Jupiter: 1.9 * 10^24 tons. Roughly 226 billion times as heavy as a large comet.
Looking at that, I don't worry a lot about a comet passing between Sun and Earth. I don't expect huge tidal waves unless it actually hits Earth.
just-me wrote:
Just look at the fact that earth had such a close call and defied the laws of gravity.
It didn't.
The video claims the presenter is a physicist. I find that hard to believe. If he ever studied physics, he decided to ignore what he learned.
You mentioned the dwarf planet Eris. I'm not sure I understand the connection. Did you mean that Eris was the object twice the size of Jupiter that passed inside Earth's orbit? Eris' closest approach to the sun is 37.77 times as far from the sun as Earth.