It's very hard to destroy the Universe

When they began doing experiements in making the atomic bomb, there was some speculation that they might set off a universe-destroying chain reaction. However, I believe those worries were unfounded, because if it were easy, one of the Billions of alien races out there would have done it already.

So all this business about the danger that nukes or weird physics experiments will set off some Universe-Destroying Chain Reaction is bunk. This applies for the faster than light speed chain reactions. I believe it's still possible that some race has started a slow wave of destruction that's racing here now.

It's the negative counterpart to the anthropic principle.

In response to the threat of our sun becoming 11% hotter in the next 1.1 billion years, hard working scientists may have an answer that could move Earth into a “cooler” orbit. The plan devised by Don Korycansky and his partners in science involves attaching a fusion powered rocket or solar sail to an asteroid some 62 miles wide and “nudging” it from it’s home in the Kuiper Belt orbiting in the region of Pluto into a new orbit closer to Earth. This near miss every 6000 years would give the Earth a gravity tug to help us move from our 93 million mile distance from the sun, to a new orbit of 140 million miles.

Possible side effects from playing marbles with the heavenly bodies are:

• Mars and Venus seem to need the earth to stay in their orbits.
• These “tugs” could accelerate the Earth’s rotation, shortening days to just a few hours.
• The moon would not necessarily care to move with us to our new address, playing havoc with the tides .
• Jupiter could move some 10 million miles closer to the sun, dislodging it’s asteroid belt to rain down upon the Earth.
• And of course, a little ill math could put this 62 mile wide rock into an orbit that has it slamming into the earth which would sterilize the biosphere.

This all says to me that the human race is very close to extending its self-centered destructive capability to the stars.
The human race is amazing and I have every confidence that we will be able to figure out how to destroy the Universe within our lifetime.

Back in the 1970s when CERN started doing pi meson production, a paper was published in a Russian journal that suggested the experiments might destroy the universe. I heard about this at a talk in Edinburgh title The vacuum as seen from Moscow.

You see pi mesons are produced by colliding heavy nuclei at relativistic speeds. The paper claimed that this had probably not happened before. When the ambient energy density of the universe was high enough to accelerate particles to ultrarelativisitc speeds there were no heavy particles, this was after the big bang during nucleosynthesis. The heavy elements didn't get produced until later when stars had formed. By this time there was not enough energy lying around to speed the particles up.

The Russians claimed that if some models for the vacuum were correct then we lived in a universe which had a false vacuum with a lower energy vacuum beneath it. The acceleration and collions of the heavy particles could cause a tunnelling event between the two vacua. Now the true vacuum would be in a lower energy state then our false vacuum and the initial tunnelling event would continue as our universe fell through to its lowest possible energy state. The breach would expand from its point of inception at the speed of light.

People stopped the experiments for a while and thought about this. Then someone realised that no, actually there are places in the universe which have heavy elements and much higher energies than can be produced in experiments on earth. These are the cores of galaxies where AGN are formed. If the Russian argument could hold true then it would probably already have happened at the heart of some AGN. Since we were still here and hadn't seen anything like a wall of false vacuum approacing us from any direction in the universe (though as bdonlan pointed out how do you see something moving at the speed of light until it reaches you!, hey I was just reporting ;) ) then it was likely that the experiments could go ahead. Indeed they did and quite a few Nobel prizes were awarded on the way.

In response to lawnjart, the toys we have to play with are feeble in comparison to the energies available to astrophysical objects. I have every confidence in our ability to destroy ourselves, and it is my belief in our insignificance that gives me confidence that the universe has nothing to worry about.

...Especially when the good old Americans are there to prevent those dirty Communists from doing it.

According to several tabloid magazines of the last decade, the Communists in China have tried on several accounts to destroy the world by knocking the Earth out of its orbit. In the 1960's, 3 million Communists jumped simultaneously in China on the idea that the force of 3 million people hitting the Earth would knock us out of orbit. Fortunately, the Americans foiled their plan; 3 million Americans also jumped at the same time as the Chinese, thus nullifying the original Communist action. Apparently the Chinese have tried this same technique twice since, each time stopped by the heroic Americans.

Unfortunately for Star, however, the laws of physics get in the way of the story. The normal force of the earth against the Communist impact(by definition equal to the force of the people) would nullify the effect of the jump on its own.