The Mars rover Curiosity is driving over a dried-up stream bed. Looking at the gravel under Curiosity, NASA scientists say the water must have flowed about 1 m/s and been somewhere between 10 cm and a metre deep. That’s a lot of water, although it was probably billions of years ago.
Isaac Newton’s Philosophiæ Naturalis Principia Mathematica, (Latin for “Mathematical Principles of Natural Philosophy”) was published 325 years ago today, on 5 July 1687. This is the book that laid out Newtonian Physics. It’s an astonishing book. In the section on the orbit of the planets and their moons, Newton showed that gravity depends on the square of the distance between massive bodies, and that the gravity acts as though it’s…
Modern telescopes have mirrors made of a material called vitro ceramic, which keeps its size and shape in spite of changes in temperature, covered with a very thin layer of aluminium. Domestic mirrors have glass in front of the aluminium, to protect it, but that means that the light passes through the glass twice – coming and going – which degrades the image. So telescope mirrors have the aluminium…
Yesterday the maintenance team took the tertiary mirror out of the huge GranTeCan telescope, and I was invited to take photos. (Starlight hits the huge primary mirror first, then bounces up to the smaller secondary mirror at the top of the telescope, then back down into a tube called the baffle to the flat tertiary at 45º, which sends it to the scientific instruments at the sides. The tertiary is elliptical, and…
Sometimes it snows on Mars. In autumn, the snow is probably water ice, and in the depths of winter, when temperatures drop to -125 º C, it’s carbon dioxide snow. The atmosphere is thin and dry, and the temperature drops very fast after sunset, so the snow flakes are tiny, about 7 microns in diameter, like a human red blood cell. In fact, it’s a lot like the diamond ice…
The Starlight Initiative has officially recognised La Palma as a “Starlight destination“, meaning that the island has really starry skies and really good activities for tourists to enjoy those skies. Among other things, the auditors were impressed by La Palma’s growing number of hiking trails and viewpoints used for astrotourism, its archaeological sites connected with astronomy, the progress towards a visitor centre at the Roque de Los Muchachos, and the country cottages…