How old is the earth? Short answer: 4,540,000,00/H30 Earth-years, plus or minus 1%. Long answer: We don't know exactly because direct dating of the earliest material on the surface of the Earth will only tell use a minimum age; Prior to that, the Earth's surface was probably molten, and even after that, it may be that the earliest non-molten material has been recycled into the planet's interior by tectonic processes. Also, the earth is a big round ball of stuff that condensed into this shape from part of a large disk-shaped blob of stuff known as the Solar Nebula. When exactly, given this, did the Earth become the Earth? Since the process took millions of years, we can't pinpoint the age of the Earth more exactly than a certain range. What are the oldest rocks? The oldest rock formations on Earth are between about 3.8 and 3.9 billion years old., but there are older bits of more ancient rocks that were incorporated into these early rocks, and they date to something closer to 4.4 … [Read more...] about How old is the earth, and how do we know?
Reference table earth science
These are my suggestions, mostly books, for holiday gifts that have some sort of science relevance. See this guide for gift ideas for kids. (There is a pretty good chance that there is an idea or two in the Kids Guide for the adult in your life, depending on the adult.) For your Uncle Bob Get ready for your favorite science-denying uncle, whom we all know of as "Uncle Bob" (though he goes by many different names) with these two important books related to climate change. If your Uncle Bob is an Evangelical Christian. Or, really, any kind of Christian. My friend Paul Douglas has co-authored a book on climate change written specifically for Evangelicals: Caring for Creation: The Evangelical's Guide to Climate Change and a Healthy Environment The book's structure swaps back and forth between science (the parts written by Paul Douglas) and scripture (the parts written by co-author Mitch Hescox). I don't know Mitch, but from the blurb I learn: "Mitch Hescox leads the Evangelical … [Read more...] about Your Science Based Holiday Gift Guide! (For adults)
It is possible that this is the most important Earth Day. Earth Day is part of the process of broadening environmental awareness and causing positive change in how we treat our planet. We are at a juncture where we must make major changes in what we do or our Grandchildren, to the extent that they can take time away from the daunting task of survival in a post-Civilization world, will curse us. I wrote a massive multpart blog post about Earth Day a four years ago, and here I'm giving you a slightly modified version of it, covering just a few aspects of the thing, and telling a couple of personal stories. There are politics, explosions, and folk singers. So put on your Love Beads and your Tie-Dyed MuuMuu and enjoy. Or not enjoy. This is not really for your enjoyment. The First Earth Day The First Earth Day. More Black and White than Green. The first Earth Day was a red letter day in the long, hard struggle to make being good to the environment … to the Earth … … [Read more...] about The Most Important Earth Day
Returning to our mostly-chronological ordering after yesterday's brief excursion, we come to one of the great problems of the 1700's, namely determining the longitude at sea. Latitude is easy to find, based on the height of the Sun at noon-- we told that story last week-- but longitude is much trickier. Thanks to the rotation of the Earth, the best way to measure longitude is by measuring time-- if you know what time it is where you are, and what time it is at some reference point (now established as Greenwich, UK), the difference between those times tells you the difference in longitude. This is relatively easy to do on land, but making a system capable of tracking the time difference on a moving ship at sea was an extremely difficult problem. It was, of course, finally cracked by a lone genius working in... Göttingen. And, OK, I skewed the presentation of that a little just to mess with Thony C. He wasn't really a lone genius, and he's not really famous. I'm talking about … [Read more...] about Advent Calendar of Science Stories 12: Time Tables
I was 28, lying on a dusty airplane runway in the Guyanese jungle, and dying. It was just a matter of time. Five bullets had ripped through me, devastating the right side of my body. Behind the wheel of an airplane, I waited for the shooting to stop and said my Act of Contrition, praying for forgiveness and waiting for the lights to go out.Story Continued Below Somehow, through the encroaching darkness of my final thoughts, I saw my 87-year-old Grandma Emma. All I could think was I am not going to make Grandma live through my funeral. I couldn’t bear the vision of her sitting in front of my casket. Breathing heavily, I pulled myself to my feet, stumbled to the plane’s baggage compartment and took shelter. I’d come to Guyana as a congressional aide on a fact-finding mission. In the months leading up to the trip, my boss, Congressman Leo Ryan, had been contacted by worried constituents whose loved ones were members of a San Francisco-based religious group called the … [Read more...] about Surviving Jonestown