curious222 said:
he doesn't answer twitter
He's responding to tweets from various people, so do you mean you have already asked and he's not answered your two questions?
But is it important that Siegel be the person to answer your questions? And is your Big Bang question raised by this
Siegel article?
If so, rest assured that he does not know what happened before the Big Bang. Nobody does. There are ideas about this, but our physics breaks down trying to explain anything 'before' and conditions during mean we need to infer what was going on, we can't observe it directly. Fortunately, there are a lot of smart and patient people on Physics Forum who can assist in your understanding of this...if you're prepared to do your homework and show willing of at least trying to inform yourself, rather than expecting, as
@Ibix noted, other people to do your googling for you.
Now, with your "Does he believe in infinite universes?" question, are you asking about the multiverse (which is what I think)? Or are you asking whether our universe is infinite? If it's what I think, then you could have answered your own question with a quick search, because Siegel argues that there
must be a multiverse. Not everyone agrees with him, though, so his view is suggestive, not definitive.