 We, in recent history, the recent 30 years have gone through a dramatic climate change on our planet. When I was growing up in the 50s and 60s and kind of learning about science, we were in what's now considered kind of the normal period. You know, we defined climate by a 30-year average, 1950 to 1980. And after 1980, there was a dramatic warming and we're still experiencing this warming. So now we're in an abnormal period compared to those earlier 30 years. And we believe the primary cause of that is the emission of so-called greenhouse gases like carbon dioxide. People have probably heard of that. But also influenced by other things in the atmosphere like the ozone layer that blocks ultraviolet light that would otherwise be giving us skin cancer and so on down at the surface. So we've gone through this dramatic change and however in past climate, before human population grew to the 7 billion plus that we are now, still there was climate change and one of the major players in the past has been the sun. So the question arises, how much is the sun influencing things now? And is the sun tending to add to the global warming or make it less than it would otherwise be? And so that's something we're trying to understand.