Why did christians kill Galileo Galilei?

Was he ruining their business so badly when he discovered that the Earth wasn't the center of the Universe?

Because he was searching for the truth instead of being brainwashed by fairy tales.

Basically, yeah.

at that times they considered his new discoveries "against the church"

You need a few more facts...

Under the sentence of imprisonment Galileo remained till his death in 1642. It is, however, untrue to speak of him as in any proper sense a "prisoner". As his Protestant biographer, von Gebler, tells us, "One glance at the truest historical source for the famous trial, would convince any one that Galileo spent altogether twenty-two days in the buildings of the Holy Office (i.e. the Inquisition), and even then not in a prison cell with barred windows, but in the handsome and commodious apartment of an official of the Inquisition." For the rest, he was allowed to use as his places of confinement the houses of friends, always comfortable and usually luxurious. It is wholly untrue that he was -- as is constantly stated -- either tortured or blinded by his persecutors -- though in 1637, five years before his death, he became totally blind -- or that he was refused burial in consecrated ground. On the contrary, although the pope (Urban VIII) did not allow a monument to be erected over his tomb, he sent his special blessing to the dying man, who was interred not only in consecrated ground, but within the church of Santa Croce at Florence.

1. Because he was a threat.

2. Because he wasn't a Christian.

Same two reasons for everyone persecuted by Christians.

Most religions rely on ignorance and superstition.

The Catholic church has always opposed education. And, always will.

He wasn't really a prisoner, and the Catholic church didn't really try to ban education. Popes always encouraged expanding knowledge:

"His offending Dialogue was banned; and in an action not announced at the trial, publication of any of his works was forbidden, including any he might write in the future."

But, it all worked, out. The pope apologized 300 years later:

"On 31 October 1992, Pope John Paul II expressed regret for how the Galileo affair was handled, as the result of a study conducted by the Pontifical Council for Culture."

because he smelled like *** and cat-food

He pissed them off, man.

That is the problem with religion, at its source is power, to control that power priests must keep the masses undoubting, it is the truth, it is why I turned my back upon religion long ago.

HE MUST HAVE BEEN GAY GAY GAY!!!

I don't know if it had anything to do with their faith at the time, but I do know it had to do with science.

Galileo discovered the sun was the center of the universe, but at that time no one wanted to accept that. They always thought that the Earth was. He was put in punished because his ideas where not accepted. In the end he was right.

Well, they only imprisoned him. They didn't kill him.

It was the church and they were mad cuz his theories said they were wrong and he could proove it.

But from an existentialist perspective, we are the center of the universe.

christian knew the earth run and heaven above them year ago

cuz his discovery opposed the church's doctrines-they couldnt stand the idea that they were not the center n the most important thing in the universe

Ok first off he was killed by the Catholics, the only religion at the time. With his discovery of the sun at the center and not the earth he essentially shook the belief that Man was at the center of the universe. That and some of his other discoveries got him imprisoned for Heresy, a deadly crime during the early renaissance. The Holy Roman Church was in charge of daily life and to have such a notion that the sun was still just didn't sit well with them.

because christians are evil people

It should be noted that Galileo was never in a dungeon or tortured; during the Inquisition process he stayed mostly at the house of the Tuscan ambassador to the Vatican and for a short time in a comfortable apartment in the Inquisition building.

After the process he spent six months at the palace of Ascanio Piccolomini (c. 1590-1671), the archbishop of Siena and a friend and patron, and then moved into a villa near Arcetri, in the hills above Florence. He spent the rest of his life there.

he died he died on January 8, 1642.
no one killed him...you need to study your history

Would you like to restate your question after reading all
these good answers?
I Corinthians 13;8a, Love never fails!!!!!

Of course he be ruinin' our business
The bible did mention that the earth was the center of the universe especially the verse where Joshua stops the Sun (FYI: the earth is the one that revolves around the sun, not vice versa, so basically the sun stays put in it's position and the earth is the one that moves around). with that being said, considering that the bible is the word of god or inspired by god. Yes Galileo was doing a blaspmemous deed! The Bible is never wrong! The whole universe is Geocentric!
......Just kidding, let's just be fair and admit that some of the contents of the bible does contradict science.