The late Professor Stephen Hawking revealed his answers to the 10 "big questions" he was often asked in a new book published six months after his death.
In "Brief Answers to the Big Questions," the British scientific hero admitted he thought "there is no god" and that humans would eventually live in space.
Professor Hawking passed away in March this year after a lifelong battle with Motor Neurone Disease.
An acclaimed theoretical physicist, cosmologist and author, Hawking was one of Britain's finest minds.
CLICK HERE FOR MORE FROM THE SUN.
He's now revealed his thoughts on some of the toughest questions in science today, including the existence of God, time travel and the future of artificial intelligence.
You can read his answers to 10 of the most pressing questions below.
1. Space colonization
"I expect that within the next hundred years we will be able to travel anywhere in the solar system, except maybe the outer planets," Hawking he explained.
The late professor described how humans are "standing at the threshold of a new era", and said colonizing other planets is no longer science fiction.
"I am optimistic that we will ultimately create viable habitats for the human race on other planets," he wrote.
"We will transcend the Earth and learn to exist in space."
2. The future of A.I.
Hawking is convinced that computers are "likely to overtake humans in intelligence" at some point in the next 100 years.
"We may face an intelligence explosion that ultimately results in machines whose intelligence exceeds ours by more than ours exceeds that of snails," he said.
He also warned over the risks: "When that happens, we will need to ensure that the computers have goals aligned with ours.
"It's tempting to dismiss the notion of highly intelligent machines as mere science fiction, but this would be a mistake — and potentially our worst mistake ever."
3. Genetic engineering
Hawking doesn't only fear AI — but the risks of genetic engineering too, saying it could "destroy the entire human race".
"A nuclear war is still the most immediate danger, but there are others, such as the release of a genetically engineered virus," he explained.
He went on: "Laws will probably be passed against genetic engineering with humans. But some people won't be able to resist the temptation to improve human characteristics, such as size of memory, resistance to disease and length of life.
"Once such superhumans appear, there are going to be major political problems with the unimproved humans who won't be able to compete."
4. The theory of everything
Hawking famously quested after developing a "theory of everything" that would explain all things.
Will it ever happen? The professor wrote: "What are the prospects that we will discover this complete theory in the next millennium? "I would say they were very good, but then I'm an optimist.
"In 1980 I said I thought there was a 50-50 chance that we would discover a complete unified theory in the next 20 years. "We have made some remarkable progress in the period since then, but the final theory seems about the same distance away."
Stephen Hawking had major concerns about Brexit too, his book reveals.
"We are also in danger of becoming culturally isolated and insular, and increasingly remote from where progress is being made.
"Unfortunately we cannot go back in time.
"With Brexit and Trump now exerting new forces in relation to immigration and the development of education, we are witnessing a global revolt against experts, which includes scientists."
He added: "So what can we do to secure the future of science and technology education? I return to my teacher, Mr. Tahta. The basis for the future of education must lie in schools and inspiring teachers."
6. The future of scientific discovery
Similarly, Hawking is very concerned about the "low esteem" in which scientists are held — and says this is having "serious consequences."
"We live in a society that is increasingly governed by science and technology, yet fewer and fewer young people want to go into science," the late professor wrote.
"A new and ambitious space programme would excite the young and stimulate them into entering a wide range of sciences, not just astrophysics and space science."
He went on: "I am advocating that all young people should be familiar with and confident around scientific subjects, whatever they chose to do.
"They need to be scientifically literate, and inspired to engage with developments in science and technology in order to learn more."
7. Climate change
Like most scientists, Stephen Hawking has warned about the risks of climate change.
In his book, he explained that we may simply be too late to reverse the problems climate change causes.
"Global warming is caused by all of us. We want cars, travel and a better standard of living.
"The trouble is, by the time people realise what is happening, it may be too late. As we stand on the brink of a Second Nuclear Age and a period of unprecedented climate change, scientists have a special responsibility, once again, to inform the public and to advise leaders about the perils that humanity faces.
"As scientists, we understand the dangers of nuclear weapons, and their devastating effects, and we are learning how human activities and technologies are affecting climate systems in ways that may forever change life on Earth."
8. The Moon landing
There's plenty of crackpot skepticism over the U.S.'s legendary 1969 moon landing, but Hawking isn't convinced by conspiracies — and said it was a pivotal moment for humankind.
"On 20 July, 1969, Buzz Aldrin and Neil Armstrong landed on the surface of the Moon. It changed the future of the human race.
"I was 27 at the time, a researcher at Cambridge, and I missed it. I was at a meeting on singularities in Liverpool and listening to a lecture by René Thom on catastrophe theory when the landing took place.
"There was no catch-up TV in those days, and we didn’t have a television, but my son aged two described it to me."
9. Time travel
Stephen Hawking said that time travel is an important subject, but "one has to be careful not to be labelled a crank."
He said he was concerned that applying for research grants for time travel research would be unsuccessful.
"No government agency could afford to be seen to be spending public money as way out as time travel," Hawking wrote.
"Instead one has to use technical terms like closed time-like curves which are code for time travel.
"Yet it is a very serious question. Since general relativity can permit time travel, does it allow it in our universe?"
Hawking famously held a party for time travelers in his Cambridge college in 2009.
To make sure only time travelers came, he sent out the invitations after the party took place — but sadly, no one came.
The late professor was an esteemed scholar, and so spent much of his time thinking about the world's biggest problems.
And when it comes to religion, it's no surprise that Professor Hawking had plenty of opinions.
"Do I have faith? We are each free to believe what we want, and it’s my view that the simplest explanation is that there is no God.
"No one created the universe and no one directs our fate.
"This leads me to a profound realisation: there is probably no heaven and afterlife either.
"I think belief in an afterlife is just wishful thinking. There is no reliable evidence for it, and it flies in the face of everything we know in science.
"I think that when we die we return to dust. But there’s a sense in which we live on, in our influence, and in our genes that we pass on to our children.
"We have this one life to appreciate the grand design of the universe, and for that I am extremely grateful."
This story originally appeared on The Sun.