There are eight known planets in our solar system. Beyond the orbit of Neptune, there are small icy worlds like Pluto and Eris, but none that rival the planets in size. But could there be a planet lurking in the depths of our solar system? Read More
Citation Needed
I get a lot of email from folks with pseudoscience claims. It could be that the Earth is actually flat, or that the Sun is powered by electricity, or that Einstein was wrong about gravity. Bonus points if the email also calls me an idiot or part of the astronomical illuminati. But in the world of pseudoscience another popular approach is to make a claim based upon some image. There’s no referenced source or clear history of the image, just a picture and a claim. But even for pseudoscience, this is just being lazy, because in the information age images can often be tracked to their source with minimal effort.Read More
The Attraction Of A Star
In 1919 Arthur Eddington traveled to the island of Principe off the coast of West Africa to photograph a total eclipse. Mission was to observe the apparent shift of nearby stars by the Sun’s gravity. His experiment was a success, and it verified Einstein’s gravitational theory of general relativity. Since then, we have observed the gravitational deflection of starlight by the Sun numerous times. We have also seen the deflection of the light from distant galaxies, but we haven’t seen the deflection of distant starlight by another star. The gravitational effect of a single star is extraordinarily small. But recently a team has observed the deflection of starlight by a single white dwarf star.Read More
Black Holes And Gravitons
During the Archean Eon of planet Earth, when life was figuring out how to harness energy from the Sun, two black holes in a distant galaxy merged with a ripple of gravitational waves. Over the next 2.9 billion years these ripples traversed a vast and empty space, while on Earth a plucky little species of bipeds learned to use lasers and mirrors to measure gravitational vibrations smaller than the nucleus of an atom. When the gravitational ripples reach Earth, they become humanity’s third detection of merging black holes. Read More
Lunar Reconnaissance Orbiter Hit By Meteoroid
Impact strikes are a rare but dangerous threat to spacecraft. The highest threat is for spacecraft in near-Earth orbit, where decades of satellite debris have accumulated. Given the tremendous speeds of orbiting spacecraft, even a fleck of paint can pose a threat. Beyond Earth orbit the threat is less, but it isn’t zero, as demonstrated by a rare impact with the Lunar Reconnaissance Orbiter (LRO) currently orbiting the Moon. Read More
How To Define Distance In An Expanding Universe
Recently the Sloan Digital Sky Survey (SDSS) has completed the largest map of the universe thus far. The map focuses on the positions of quasars. These objects are powered by supermassive black holes in the centers of galaxies, and are so bright they can be seen from the farthest regions of the cosmos. Most quasars are so far away that we have to redefine what “distance” means. In an expanding universe, distance can be defined in a variety of ways. Read More
The Rains Of Mars
Mars is a cold, arid world with a thin atmosphere, but that wasn’t always so. In its youth Mars was wet with rivers and oceans. Presumably that also means young Mars had rainfall. But how much did it rain on Mars? New research proves not only did it rain on Mars, the rains were strong enough to shape the planet’s surface. Read More
A Jovian Eclipse Reveals Lava Lakes On Io
Io is a violent world. Tortured by the gravitational forces of Jupiter, it erupts with sulphur and lava. Our own planet has volcanoes and lava flows, but it pales in comparison to Io. Read More
A Young Star System Holds Clues About The History Of Our Own
Ten light years away there is a star that could tell us about the origins of our solar system. Known as Epsilon Eridani, it is a bit smaller and cooler than our Sun, but similar in composition. It is also only about 500 million years old, giving us a view of what our own solar system may have been like in its youth. New work now finds the system is similar to our own. Read More