Space

Again, this is just for fun. What would we look like to aliens, and would they be able to tell which humans look most attractive to us? So, to get us started, which of these faces do you find exceptionally attractive? Flock of sheep, (photo by Keith Weller for the Agricultural Research Service) It's a similar question. They'd think we all look similar. They would probably notice differences in the colour of our clothes first - that is if they see colour the same way, which they probably wouldn't. Then - as a minor detail, that we have different coloured hair and some don't have any hair…

This is just for fun. At first sight this seems impossible - the smallest stars are heavier than the heaviest planets, and how can something heavier orbit something that is lighter? But what if you have a very dense star and very large very low density planet? And if you interpret "orbiting it" as "having barycenter (the "center of mass of the system") within the planet"? Also, could a star sometimes be lighter than a planet, is that possible at all? I'll also describe a way that a heavier object can, in a way, "orbit" a lighter one - a way to get a heavier star move in such a way that the…

New research predicts that Earth has more than 1,500 undiscovered minerals and that the exact mineral diversity of our planet is unique and could not be duplicated anywhere in the cosmos. Minerals form from novel combinations of elements. These combinations can be facilitated by both geological activity, including volcanoes, plate tectonics, and water-rock interactions, and biological activity, such as chemical reactions with oxygen and organic material. Nearly a decade ago, Carnegie's Robert Hazen developed the idea that the diversity explosion of planet's minerals from the dozen present at…

Perhaps you saw the news recently about astronauts in the International Space Station eating their first home grown lettuce? It's just a beginning, but in the future, could they grow all their own food and get all their oxygen from plants? The astronauts of the ISS eating their first home grown lettuce in space. Actually, it's a first only for US astronauts. The Russian cosmonauts have been eating half their crop on the ISS since 2003. The US astronauts have just had the food passed as okay for them to eat it as well. Could they grow all their own food and get all their own oxygen from…

One day, it might be possible to detect the spread of life among the stars through panspermia--a hypothetical process of life distributed throughout the Milky Way by asteroids, comets, and even spacecraft. Henry Lin and Abraham Loeb of the Harvard-Smithsonian Center for Astrophysics propose, “If future surveys detect biosignatures in the atmospheres of exoplanets,” it ought to be possible to detect the spread of life between stars even without knowing how life spread from host star to host star. That is, we probably wouldn’t be able to detect the mechanisms of panspermia such as asteroid,…

Perhaps you saw the news recently about astronauts in the International Space Station eating their first home grown lettuce? It's just a beginning, but in the future, could they grow all their own food and get all their oxygen from plants? A little known series of experiments in Russia in the 1960s through to the 1980s suggests that they could. The research continues to this day, and we may see the first steps towards such a system taken in space in the near future. The crew of the ISS eating their first home grown lettuce in space. Could they grow all their own food and get all their own…

Science fiction movies about aliens threatening the Earth routinely ascribe them the motive of coming here to steal our resources, most often our water. This is ill thought-out, as water is actually extremely common. Any civilization coming to our solar system in need of water (either to drink or to make rocket fuel) would be foolish to plunge all the way inwards to the Earth, from where they’d have to haul their booty back against the pull of the sun’s gravity. Until recently, we believed that the Earth was the only body in the solar system that had water in liquid form. While it is true…

Is the ISS the most expensive single human artifact ever, after adjusting for inflation? Well, to start with, it's a whole lot more expensive than a medieval cathedral anyway. First we need an estimate of the cost of the ISS, and this article in the Space Review estimates the total cost up to 2015 as $150 billion (in 2010 dollars). That's the total cost including all the international partners. So, how much did it cost to build a medieval cathedral? There's an estimate here that the cost of rebuilding Chatres between 1194 and 1223 after much of it was destroyed in a fire amounted to…

Well, a whole lot more expensive than a cathedral anyway. There's an estimate here that the cost of rebuilding Chatres between 1194 and 1223 amounted to around fifty million dollars: Cathedrals. Chatres Cathedral - cost to rebuild in the early twelfth century about 50 million dollars in today's money. You could build 3,000 of these for the cost of the ISS, using medieval methods. So, if that's a good estimate, you could build three thousand medieval cathedrals for the cost of the ISS. Even if that estimate was an order of magnitude out, it's clear that it is way more expensive than a…

A team of researchers has discovered a Jupiter-like planet within a young system that could provide a new understanding of how planets formed around our sun. The new planet, called 51 Eridani b, is the first exoplanet discovered by the Gemini Planet Imager (GPI), a new instrument operated by an international collaboration headed by Bruce Macintosh, a professor of physics in the Kavli Institute at Stanford University. It is a million times fainter than its star and shows the strongest methane signature ever detected on an alien planet, which should yield additional clues as to how the planet…