A direct consequence of Einstein’s theory of general relativity, and an observational way to prove it, is gravitational lensing. It requires a powerful gravitational source to work, such as a galaxy or cluster of galaxies. It works in a similar way to a lens of glass, where rays of light are bent toward a single source, increasing the brightness. In this case, instead of glass, the bending of the rays is due to the curvature of space. Light rays coming from the source would otherwise miss Earth, but instead are bent toward us when there is a massive object in front of it. It’s...
I love false-colour images. They reveal detail that you can’t see in real life, but they also highlight things in an artistic way. For me it’s an excellent marriage of art and science, and as a communicator it helps me get concepts across in an accessible way. So when I saw the APOD image of Saturn from earlier this week, I had to discuss it. Saturn never has looked this way, and it never will. The colours are vivid and unrealistic, but they show the differences in three distinct but close wavelengths of light on the electromagnetic spectrum. All of...
The Crab Nebula, as it’s commonly known, is connected to one of the earliest recorded supernova explosions. In 1054 AD, Chinese Astronomers saw the explosion of this supernova as an incredibly bright star in the sky lasting about two weeks, before fading. Now, nearly 1000 years later, the explosion is still happening as an expanding shock front rich in heavy elements moves through the interstellar medium. When the shock front hits dust or gas it is slowed down, giving the resulting nebula a unique shape. In this case, it looks like a crab. The supernova wasn’t exactly the death of the original...
Since the arrival of the Dawn spacecraft in March of 2015, we have seen tremendous views of the dwarf planet Ceres. Lying within the asteroid belt, it is revealed to be a frozen world of ice and rock, with many interesting features. None of these features had generated more intrigue than the famous bright spot in the bottom of what is now called the Occator crater. The icy spot has had astronomers guessing for months whether it is a cryovolcano, water ice, frozen carbon dioxide, or something even more strange and rare. As the Dawn spacecraft has moved into a...
The concept of Panspermia is a description of all life in the Galaxy having been seeded by other life, all originating at one point. This life can hitch a ride from star to star on comets, meteorites, and rogue planets. It’s true we have never found evidence for life outside of our own home planet, but if panspermia is a viable theory, it could mean that life is everywhere, just waiting for us to find it. In a new study from astronomers as the Harvard-Smithsonian Centre for Astrophysics, panspermia creates ‘oases’ where pockets of life form. As life is able...
