There are a lot of very smart people working in astronomy, they review each other’s work, and they compete for jobs and funding. Does it really seem likely that none of them have thought to validate basic assumptions?
Having family members who do that for a living, I can tell you that’s a huge chunk of the job. Astronomers all know that they have significant limitations in the data that they can collect and spend a lot of time thinking about ways they can test different theories. It would be a career-making move if some grad student could come up with a new explanation which changes the previous understanding and given the ratio of degrees granted to jobs the incentives really wouldn’t favor covering anything up.
Having family members who do that for a living, I can tell you that’s a huge chunk of the job. Astronomers all know that they have significant limitations in the data that they can collect and spend a lot of time thinking about ways they can test different theories. It would be a career-making move if some grad student could come up with a new explanation which changes the previous understanding and given the ratio of degrees granted to jobs the incentives really wouldn’t favor covering anything up.