But it is only a matter of belief. If Jesus was really who he claimed to be, why did he jet up to heaven instead of sticking around to the present day after he 'resurrected', then there would be no doubt about it!
1) Would you believe anyone who claimed to be 2000 years old?
2) In human form, even God can only be in one place at a time: by returning to heaven, he made it possible for the advocate/comforter/counsellor/... (aka the Holy Spirit) to be in more than one place at a time.
3) How much science is about belief? Have you actually experienced/been present at any of the simple experiments that shape modern scientific thinking, let alone any of the more complex ones?