I'm offering this movie a 5 because I feel generous. I mean at least, the kids were looking through the correct side of the telescope and they even depicted a meteor shower relatively accurately. Well, except that the full moon would have made watching a meteor shower much more difficult and that it appeared to be night time, simultaneously, everywhere on Earth. erroneously
Oh my... and did they really need to get a religious debate going in the first few minutes? Really? Was it necessary? Anyhow, this with all the other scientific talk... was mostly nonsense. BTW, Astronomers don't use telescopes to watch meteor showers! Another ridiculous moment is when Natasha Henstridge character kept stating she didn't understand something she clearly should have understood (hint: when an object takes on significantly more mass - Kepler's law clearly states what will happen. It is as if she and the other scientists are unaware of basic physics).
The meteorite hits were rather anticlimactic (read quite unrealistic).
What else did they get right (which helped earn the 5 out of 10)? - Meteorites vs Meteors (right) - Meteorites are not magnetic (mostly true)
Bottom line, this is just a story. Certainly, the events depicted could happen but the reality would be very different. I would have given this story a 7 out of 10 if it had ended at part 1. Part 2, while rather emotional, played out like any other disaster movie with a rather predictable ending.