In order to understand how we study the universe, we need to talk a little bit about light. Light is a form of energy. Its wavelength tells us its energy and color. Spectroscopy allows us to analyze those colors and determine an object’s temperature, density, spin, motion, and chemical composition.
Today Phil’s explaining the stars and how they can be categorized using their spectra. Together with their distance, this provides a wealth of information about them including their luminosity, size, and temperature. The HR diagram plots stars’ luminosity versus temperature, and most stars fall along the main sequence, where they live most of their lives.
The most amazing images of the universe captured by the space telescope, and a look at plans to launch a new and more advanced satellite in 2018. In this updated version of "Hubble's Amazing Journey” we reveal some of Hubble's latest observations: It has produced some of the most awe-inspiring images ever taken of the universe. But what is often forgotten about the Hubble Space Telescope is that after its launch 25 years ago it was originally labelled an embarrassing and expensive flop.
2016 • Astronomy
Active galaxies pour out lots of energy, due to their central supermassive black holes gobbling down matter. Galaxies tend not to be loners, but instead exist in smaller groups and larger clusters. Our Milky Way is part of the Local Group, and will one day collide with the Andromeda galaxy. Clusters of galaxies also clump together to form superclusters, the largest structures in the Universe. In total, there are hundreds of billions of galaxies in the Universe.
What would happen if the sun took out our electrical power grid for an entire year? It may sound like the plot of a sci-fi movie, but this doomsday scenario could actually happen. Despite its calm appearance, the sun is a violent place, constantly releasing huge masses of energy known as coronal mass ejections. These storms have hit the earth before. The last big one struck more than 150 years ago in the Victorian era taking out worldwide telegraph service. The impact of a similar storm would be far more destructive in our modern age of hyper-connected telecommunication and total reliance on electricity and electronics. Fortunately scientists and engineers are building the world's largest solar telescope and launching the first ever spacecraft to fly to the sun to help us predict these potentially devastating events - and prepare for them.
2017 • Astronomy