> Are there Christians that are also scientists?
Absolutely. Go to
http://www.biologos.org. It's a society of Christians who are also scientists, including such luminaries as Dr. Francis Collins (human genome project; head of the NIH) and Dr. Jennifer Wiseman, astrophysicist in charge of the Hubble telescope.
> How do you guys connect Christianity with science?
I subscribe to a position known an non-concordism. It ASSUMES no correlations or parallels between biblical texts and scientific statements. We take the Bible at face value, on its own terms and science on its own terms. Science doesn't set the agenda for what biblical texts mean, and biblical text don't set the agenda for what science says.
It's a partial-view model, where science and theology are two windows on a multifaceted reality. Though science and theology each have their proper place, the barriers are both fuzzy and fluid. They can learn from each other, at times be in each other’s territory, all the while developing our separate disciplines with professionalism and respect. There is nothing simplistic about the natural world, science, medicine, or theology. Why should we expect the relationship between nature and Scripture to be anything less? The partial views model fits well with Christianity’s views of natural revelation and special revelation.
God accommodates the primitive scientific understanding of the ancients to communicate what He is really talk about. The form of the communication, in their science (such as "the firmament") is used to communicate the truth of the text (God is sovereign, for instance, or that the atmosphere is the source of our weather and climate systems). The Bible’s objective is not to give us a scientific understanding of the world. It is not offering an explanation of how the material world works from a scientific perspective. Their observations about the world were inherently theological, not naturalistic.
The Bible gives us theological perspective about the material world (God has created it, he sustains it, it is contingent on him, he is sovereign over it, etc.), but it does not give us any naturalistic insight (which is precisely what science does do).
There is no example in the Bible that new scientific revelation was being given. If that were to be the case, God would have to come out with a new edition of the Bible every year. Even our science is always changing. Instead, God chose human communicators associated with a particular time, language, and culture and communicated through them into that world, and indirectly to us. It has information for us as we are able to penetrate the message being conveyed by the human communicators to their audience.
This is not to claim the Bible and science are in conflict. They are not. Science investigates the natural world, its formative sequence, its properties, and behaviors. The Bible, in contrast, reveals God to us, as well as the purposes and meanings of life. We wouldn’t use a CT scan to determine if the Holy Spirit were in someone, and we wouldn’t use the Bible to give us the taxonomic classification of the species. And yet this is what too many people do, trying to fit the Bible and science into each other's molds. They end up distorting both.
If we never look beyond science’s grasp, we would miss all kinds of important things that explain life and make it meaningful. But if we expect the Bible to answer every question science asks, we are looking in the wrong place. In other words, each one has its rightful place in what truth it’s communicating.
> For example, how do you guys explain the vastness of space and the fact that the earth will be swallowed by the sun?
God created the vastness of space by a process that had its source in the Big Bang. The universe had a beginning, and it may also have an end. Some day, theoretically, the Earth will be swallowed by the sun. (Full Disclosure: I don't think God will wait that long to return, to create a new heaven and a new Earth, and reconcile all things to Himself.
> that if there might be alien civilizations but we might not ever be able to meet them due to the distance?
It is plausible that if other alien civilizations exist, our odds of meeting them are close to nil. When I heard Dr. Wiseman speak, she said, "We have a tendency to jump to full and intelligent civilizations elsewhere. But from a scientific perspective, we are most likely to find microbial life." She said that the obstacles of travel and communication across spans of space are prohibitive for realistic visitation.
> Did god send the asteroid that killed off the dinosaurs? If so, why?
I don't see any particular reason to believe God intentionally sent said alleged asteroid.