Dark matter is postulated to exist in order to explain the gravitational force which holds galaxies together. There is not enough visible matter to explain it. Members of the international Dark Energy Survey (DES) team – a collaborative effort to … Continue reading
In a BBC Podcast first broadcast on 11 March 2021, Melvyn Bragg and guests discuss the devastating mass extinctions of the Late Devonian Period, roughly 370 million years ago, when around 70 percent of species disappeared. Scientists are still trying … Continue reading
This conference, organised by Birkbeck Institute for the Humanities, will be held in London on 19 and 20 September 2019. Astrobiology and Big History are two relatively new intellectual disciplines, the former focussed on searching for life elsewhere in the … Continue reading
About 2.4 billion years ago there was a dramatic increase in the level of free oxygen in the Earth’s atmosphere, which led to the widespread extinction of many species of bacteria which had evolved when the atmosphere was anaerobic. Previously … Continue reading
Redshift is the name given to the change in colour of objects which are moving away from us. At normal speeds this change is so small we do not notice, but when we use powerful telescopes to look at distant … Continue reading
The images below show how galaxies similar in mass to our home galaxy, the Milky Way, evolved over time. The images taken by the NASA/ESA Hubble Space Telescope reveal that Milky Way-like galaxies grow larger in size and in stellar mass … Continue reading
In one of the most comprehensive multi-observatory galaxy surveys yet, astronomers find that galaxies like our Milky Way underwent a stellar “baby boom,” churning out stars at a prodigious rate, about 30 times faster than today. Our Sun, however, is … Continue reading
In analyzing data from deep-sky census assembled from surveys taken by NASA’s Hubble Space Telescope and other observatories, a team led by Christopher Conselice of the University of Nottingham, U.K., found that 10 times as many galaxies were packed into … Continue reading
The Orion Arm is a minor spiral arm of the Milky Way some 3,500 light-years (1,100 parsecs) across and approximately 10,000 light-years (3,100 parsecs) in length. The Solar System, including the Earth, lies within the Orion Arm. It is also … Continue reading
The Earth’s magnetic field permanently protects us from the charged particles and radiation that originate in the Sun. This shield is produced by the geodynamo, the rapid motion of huge quantities of liquid iron alloy in the Earth’s outer core. … Continue reading