If you caught a brief glimpse of the Sun during the eclipse, you’re not alone.
How Galileo’s Moons Changed The World
Galileo’s discovery of the moons of Jupiter gave us a “heavenly clock” we could use to map the Earth.
Wonder Falls
There’s a new video from Human Universe where Brian Cox shows how, in a vacuum, a bowling ball and feathers fall at the same rate. The idea that all objects fall at the same rate regardless of their mass is often attributed to Galileo. It’s commonly said that Galileo proved this fact to be true by dropping masses off the leaning tower of Pisa. But in fact it’s quite likely that Galileo never performed the experiment. Given the experimental apparatus at the time, it’s unlikely that such an experiment would be conclusive anyway. So why was Galileo convinced that objects fall at the same rate?
Raising a Glass
Glass has the useful feature of being transparent at optical wavelengths. That, and the fact that light can refract (change direction) when it passes through curved glass is what made it useful as lenses, and eventually telescopes.
Just a Phase
Yesterday I mentioned that after discovering the moons of Jupiter, Galileo went on to observe the phases of Venus, which further reinforced the idea that the Earth moved about the Sun. So just how do phases of a planet prove it revolves around the Sun?
Moons of Galileo
In the first few months of 1610, Galileo Galilei pointed a small twenty-power telescope at Jupiter. What he observed changed the way we understood the universe.
With his telescope, Galileo saw what appeared to be three faint stars in a straight line near Jupiter. The next evening he saw what appeared to be the same three stars, but it seemed Jupiter had moved in the opposite direction to its expected motion. Within a few days it became clear that Galileo wasn’t observing the motion of Jupiter relative to some faint stars, but rather these stars were moving along with Jupiter.
Engage
With the rise of online media, it is increasingly easy for anyone to present scientific ideas in ways that are entertaining and engaging. This can lead to TV shows like Cosmos, and it can also lead to documentaries such as The Principle. If you haven’t heard of it, The Principle claims that we live in a geocentric universe.
Lord of the Rings
All of the outer planets (and at least one asteroid) have ring systems, but none are nearly so bright and extensive as those of Saturn. Saturn will always be known as the ringed planet.
Massive Issues
We all know that many objects (atoms, cats, us) have mass. What you probably don’t know is that there are multiple different types of mass, and this has real physical (and astrophysical) consequences.
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