The FAS Astronomers Blog

  • The Daytime Moon

    FAS Astronomers Blog, Volume 32, Number 1. One of our favorite observation targets is the Moon. Most of the time, we observe it at night. Interestingly, the best time to see features on the Moon isn’t during a full moon – it is much too bright, but during a first or third quarter when you…

  • Asteroid 1, Dinosaurs 0

    FAS Astronomers Blog, Volume 31, Number 15. The dinosaurs ruled the Earth for millions of years. Despite their dominance, the dinosaurs disappeared. The commonly accepted theory is that a large asteroid hit the Earth, resulting in the extinction of over two thirds of the species on the planet. For more on dinosaurs, see three previous…

  • The Case of the Brontosaurus

    FAS Astronomers Blog, Volume 31, Number 14b. When I was growing up, Brontosaurus was almost as famous as T. rex. However, Othniel Marsh made a mistake (maybe). In 1877, he discovered a dinosaur, which he named Apatosaurus ajax (Marsh 1877). Two years later, in 1879, he discovered another similar dinosaur, which he named Brontosaurus excelsus…

  • The Case of the Velociraptor

    FAS Astronomers Blog, Volume 31, Number 14a. The dinosaur in the movie Jurassic Park, called Velociraptor, was modeled after another dinosaur named Deinonychus. I guess the movie name sounded scarier and it was probably easier to pronounce. Although, Gregory S. Paul classified Deinonychus as a species of Velociraptor in his 1998 book Predatory Dinosaurs of…

  • Meet The Dinosaurs

    FAS Astronomers Blog, Volume 31, Number 14. In this article, we’ll focus on several individual dinosaurs and tell you a little more about them. As noted in An Introduction to Dinosaurs and The Classification of Dinosaurs, not all dinosaurs are the same. They came in all sizes and shapes. Some were meat-eaters (carnivores) and some…

  • The Classification of Dinosaurs

    FAS Astronomers Blog, Volume 31, Number 13. As noted in An Introduction to Dinosaurs, Richard Owen (Owen 1842) created the designation Dinosauria meaning “Fearfully great lizards” or “terrible lizards” to describe the new found dinosaurs. Dinosaurs lived during the Mesozoic era and dominated the planet in the Jurassic and Cretaceous periods. In 1887, Harry Seeley…

  • An Introduction to Dinosaurs

    FAS Astronomers Blog, Volume 31, Number 12. As you look around, you might notice that there are no dinosaurs, or at least what we think of as dinosaurs. The dinosaurs ruled the Earth for millions of years before disappearing some 66 million years ago.

  • The Rise of the Vertebrates

    FAS Astronomers Blog, Volume 31, Number 11. The Earth’s history is described by geologic time, which is broken into eons, eras, periods, and epochs. The first three eons (Hadean, Archean, and Phanerozoic) are often combined into the Precambrian supereon. Today, we find ourselves in the Cenozoic era of the fourth (Phanerozoic) eon. However, as we…

  • A History of the Earth (Geologic Time)

    FAS Astronomers Blog, Volume 31, Number 10. The history of the Earth is described by geologists using something call Geologic Time. This is a timeline from the beginning of the Earth to the present day broken down into a hierarchy of four main groupings: Eons, Eras, Periods, and Epochs. Epochs are broken down further into…