全新版大学英语快速阅读:新题型版:3:3

　　《全新版大学英语（第2版 快速阅读3 新题型版）》：　　On a planet with double or triple Earth's gravity，objects would actquite differently，because the pull，or attraction，would be much stronger.A ball thrown into the air would not go very high，and it would plungequickly back to the surface of the planet.A falling flowerpot would be adeadly weapon.It would kill any lucHess pedestrian who might happen toget hit by it.Rockets far more powerful than those used on Earth would beneeded to break away from the pull ofthe planet's gravity.　　Beams oflight，however，would have no trouble at all escaping fromthis planet.Even if the force of gravity were incrcased to a million timcsthat of Earth，light beams would still not be affected.Humans on such aworld，though，would be crushed flatter than their own shadows.　　Only ifthe amount of gravity were many billions of times strongerthan Earth's would light beams bend back to the surface.That is the casewith a black hole.It is hard to imaginejust how dense and heavy black holematter is.A penny made from black hole matter would rip through yourpocket and plunge through Earth with the greatest ofease.Whcn it emergedon the other side，it would hover in the air for a moment and then plungeback through Earth.　　……