A new analysis is getting some attention, one claiming to have refined the old Drake equation and produced firmer numbers, leading to this conclusion: Under the strictest set of assumptions – where, as on Earth, life forms between 4.5bn and 5.5bn years after star formation – there are likely between four and 211 civilisations in … Continue reading 36 civilizations in the galaxy?
This is the third or fourth video I've seen of Arvin Ash, and have been impressed with how level headed his thinking is. (In other words, his biases seem to match up well with mine.) This one on how alien life might evolve strikes me as right on the money. (The first few minutes end … Continue reading The evolution of extraterrestrial life
I've discussed the difficulties of interstellar exploration before. To get a spacecraft to another star within a human lifetime requires accelerating it to an appreciable percentage of c (the speed of light), say 10-20%. In general that requires titanic amounts of energy. (Forget about the common sci-fi scenarios of going into warp drive or jumping … Continue reading The Q-Drive and the difficulty of interstellar exploration
I was very young when Neil Armstrong and Buzz Aldrin landed on the moon in 1969, so I have no memory of the landing, and only limited memory of the Apollo program in general. I think I remember seeing some of Apollo 17 on TV in 1972, the final flight to the moon. (At the … Continue reading Apollo 11 and the lost space age
In past posts, when I've written about the expansion of the universe, I've generally referred to the rate of that expansion, the Hubble constant, as being around 70 km/s/megaparsec, that is, for every megaparsec a galaxy is distant from us, it's moving away at 70 kilometers per second faster. So a galaxy 100 megapasecs away … Continue reading Is cosmology in crisis?
At Nautilus, Phil Torres argues that we should think twice about colonizing space. His reasoning appears to be that as we spread throughout the universe, we will undoubtedly diversify into different species, and that those species may come to distrust each other, and eventually try to destroy each other. Now, I've argued before that most … Continue reading The real issues with colonizing space
Gizmodo has an interesting article that someone asked my thoughts on. Part of their "Giz asks" series, it asks various physicists what's at the edge of the universe? The physicists polled include Sean Carroll, Jo Dunkley, Jessie Shelton, Michael Troxel, Abigail Vieregg, and Arthur B. Kosowsky. They all give similar answers, that space isn't known … Continue reading What’s at the edge of the universe?
I've always loved space opera, but when I was growing up, as I learned more about science, I discovered that a lot of the tropes in space opera are problematic. Space operas, to tell adventure stories among the stars, often have to make compromises. One of the earliest and most pervasive is FTL (faster than … Continue reading Why faster than light travel is inevitably also time travel
Over the weekend, Sean Carroll put up a blog post to address common misconceptions about cosmology. I understood most of his points, but was confused when I saw this one: Dark energy is not a new force; it’s a new substance. The force causing the universe to accelerate is gravity. Carroll was referring to the accelerating … Continue reading Dark energy and repulsive gravity
There's been a lot of celebration this holiday season of the fiftieth anniversary of the Apollo 8 mission, the first time humans went into (relatively) deep space and orbited another body, the moon. I'm glad to see Apollo 8 getting some recognition. It's usually overshadowed by Apollo 11, the first mission to actually land on … Continue reading The difficulty of going to Mars