Landing humans on Mars will be hard, but keeping them alive will be even harder. NASA scientists are on the verge of designing some of the most innovative rockets and training the astronauts who will pilot them.
The expanding universe is a complicated place. During inflation the universe expanded faster than light, but that's something that actually happens all the time, it's happening right now. This doesn't violate Einstein's theory of relativity since nothing is moving through space faster than light, it's just that space itself is expanding such that far away objects are receding rapidly from each other. Common sense would dictate that objects moving away from us faster than light should be invisible, but they aren't. This is because light can travel from regions of space which are superluminal relative to us into regions that are subluminal. So our observable universe is bigger than our Hubble sphere - it's limited by the particle horizon, the distance light could travel to us since the beginning of time as we know it.
Set to the words of Carl Sagan, Pale Blue Dot is an animation that situates human history against the tapestry of the cosmos. Using a eclectic combination of art styles woven seamlessly together through music and visuals, the animation seeks to remind us that regardless of our differences, we are one species living together on the planet we call Earth.
2015 • Astronomy
There are Black Holes, and then there are Monster Black Holes -- containing several million to ten billion times the mass of our Sun! They've been discovered in the center of many galaxies. But they don't just absorb everything around them...in fact, they may be key to forming new galaxies.