When seen in the night sky, Mars is a burnt-reddish color. It’s sometimes brighter and sometimes dimmer as over the months and years it moves against the background stars. Sometimes it appears to stop along its starry path and reverse direction for a while, exhibiting what is known as retrograde motion. With its bloody color and strange motion through the sky, it is perhaps not surprising that it is named after the Roman god of war.
Broken World
The view of Earth from space often evokes thoughts of an Eden. That pale blue dot that cradles humanity. But our planet’s fragile beauty was born from violent collisions large and small.
Cautionary Tale
Venus is the second planet from the Sun, and the most like Earth in terms of its mass (80% Earth’s) and size (95% Earth’s). In almost every other aspect it is radically different. It has a thick, carbon dioxide atmosphere, little water, a weak magnetic field, and a surface temperature of 740 K (860 F, 460 C). Despite this radical difference, early Venus was a wet world much like early Earth. We know from the levels of hydrogen and deuterium in Venus’ atmosphere that it too had a wet past. But somehow Venus and Earth diverged.
Alas, Poor Ceres
In 1801 a new planet was discovered in our solar system. Just twenty years earlier the planet Uranus was discovered beyond the orbit of Saturn, and was the first planet discovered since the dawn of civilization. This new planet was named after the Roman goddess of agriculture, Ceres.
Icy Hot
Mercury is the closest planet to the Sun. You might think that means it is also the hottest planet, but that award goes to Venus with its thick, heat-trapping atmosphere. Mercury can be listed as one of the hottest planets in the solar system, but also one of the coldest.
Signal to Noise
My professional work focuses on two things: astrophysics and science communication. In astrophysics the challenge is often to distinguish the signal from the noise. That is, you sift through large amounts of observational data to find the useful bit of data that tells you something about the universe. In science communication the opposite is true.
Never Tell Me the Odds
Just how cluttered with rocks is the asteroid belt? The answer might surprise you.
The Great Migration
We know that the planets in our solar system migrated from their points of formation to their current positions. Just how that occurred is a bit of a mystery.
To the Test
The popular press has been abuzz about a new proposal to use the solar system to test string theory. Turns out that is a bit over-hyped. The actual paper, published in Classical and Quantum Gravity outlines an idea to use the motion of planets and moons to test what is known as the equivalence principle. The reason string theory gets mentioned …