“Hearsay” is a gossip, rumor. In the case of the disciples, it was not “hearsay”, since they personally knew Jesus and were witnesses to the miracles. Their testimony would not be “hearsay”. It would only be “hearsay” if they testified that they heard about Jesus’ miracles (but were not present or did not witness them).
Secondly, even if something is true that we witness, how many would be willing to state be willing to be tortured and die for it? That the disciples, who witnessed Christ’s miracles, were willing to be tortured and die for their beliefs gives a certain strength to them. That all of the disciples gave witness to Jesus is compelling. Even Judas gave testimony in his own way, but admitting he handed over an innocent man and going out and hanging himself.
Now, had it been one witness, we could maybe dismiss that. However, there were all the disciples and thousands of people who witnessed the miracles, apart from the disciples.
Now, you may say there are many others of faith who had martyrs. Yes, they did. However, one difference with Catholicism is that those who were martyrs witnessed first hand the miracles. With, say, Mohammad, he had private revelation, and there were no witnesses. So, it’s a bit different.
As to the Bible, when evidence comes forward be it historical, archeological, etc., it supports the Bible. So, if it says there was a census, there was. If it said …so and so was king, he was. If it says Pontius Pilate was there, he was.
Now, with UFOs, I am not aware of witnesses of it being willing to undergo torture and death to witness to their claims.
Further, I am not aware of archeological or historical and other data which would back any of these UFO claims.
Something seemed to be very convincing to the people around Jesus, that they flocked to him by the thousands. After his death and resurrection, these mostly uneducated people convinced both very educated and not educated alike to the truthfulness of their claims, which has endured 2,000 or so years.
I find all this very compelling.