I just wanted to point out that Buddhism (including, specifically, Tibetan), has no problem with evolving one's beliefs to match current scientific findings / evidence / theory / etc. ("If science proves some belief of Buddhism wrong, then Buddhism will have to change." - The Dalai Lama).
However, Demouse's question suggesting that the extreme
opposite viewpoint may hold sway:
So according to buddhism you have to perform any scientific experiment yourself otherwise you shouldn't believe it?
is taking the point too far. The prevailing Buddhist teaching on "belief" - from the deathbed quote of the Buddha accurately paraphrased by Mizuki through modern times is more or less as follows:
Blind faith is to be avoided!! You should not hold any important, life-defining beliefs just because they've been fed to you. You must evaluate their truthfulness for yourself - and if the complete evaluation of truthfulness is impractical (for instance, to borrow a FE example, until someone hands a FE'er a free roundtrip ticket on Virgin Galactic, it is impractical to "see for yourself" if the earth really is round or not), then in that case, use your best critical mind to make a judgement call as to whether the information is at least
credible, and go from there (to follow my same example, since FE'ers do not find NASA to be a credible source, it is unreasonable to ask an FE'er to accept their conclusions as fact). So be skeptical of baseless claims, but also be open-minded when the source appears trustworthy.
But don't make snap judgements when longer-term study is necessary; for instance, an overweight person going to the gym to work out for the first time would - with no other information available to him - draw the conclusion that working out makes him feel terrible! He'd be sore, tired, sweaty, probably in pain, and conclude that no good can come of this activity and he should not do it any more! However, he should look at the credible evidence that if he keeps it up, it will get easier, and that ultimately he will feel better, and be in better health. Buddhism primarily concerns itself with the evaluation of our own minds, and so this is very often the experience meditators have: "This is difficult / boring / scary / pointless / whatever!" Buddhist teaching at that point would say, yes perhaps, but be
curious about your own mind, be
open minded (on the basis that all these other many millions of people throughout history have stuck with it, obviously for SOME reason!) that it may lead to something beneficial / interesting, and then
trust the process laid out by the teachings - that is, as long as the source(s) remain(s) credible and the process continues to resonate for you over the long term.
To sum up: Successful ongoing evaluation / understanding / navigation of the phenomenal world (including our own minds) and a happy, fruitful life within it, requires a healthy balance of both skepticism (towards not only the beliefs fed to us by others, but our own preciously-held beliefs as well!) as well as open-mindedness manifested as slowness to judge, label, compartmentalize, and solidify all the thoughts / emotions / beliefs / what have you that find their way into our mind, be they externally contributed, or, again, of our own devision / construction. Try to be child-like in your wonder and curiosity about the world, but apply your well-won wisdom and discriminating awareness about what is beneficial vs. not.
I hope that helps. But do keep in mind that Buddhism really doesn't spend a lot of time worrying or debating (much less pontificating) about this kind of stuff, given its focus. Unlike many other religions, cosmology is unimportant to the Buddhist teachings; nothing would be taught, done, or viewed differently if the world were flat, globular, or shaped like the damn Easter Bunny. (In fact, Buddhism is equally unmarried to the literalness of its own religious mythology; for instance, in stories of masters of old facing scary demons, the teaching behind the story is not affected by whether or not you think of the demons as real, live demons, or as a metaphor for the ancient master's psychological "demons". In fact, such stories are generally taught at the outset as
being outright metaphorical.)