Galaxies

A supernova is the biggest explosion that ever lights up the modern universe, and happens around once a century in each of the hundreds of billions of galaxies in the cosmos. Tune in to hear about the sun and if it can go "supernova."

Tune in to hear about when a predawn conjunction will take place, and hear about all the wild features of our closest planet, Venus.

This week our eyes face the most concentrated part of our Galaxy. If it's clear, and you’re away from city lights, September's crisp air allows the Milky Way to emerge in all its glory. That’s because our own galaxy’s disk is now perpendicular to the horizon so that it crosses the entire sky and passes straight overhead.

We’re all on the lookout for nature’s patterns. The most obvious are solar rhythms — like the recent solstice. Civilizations all paid attention to solar patterns because their food production depended on it. Next in line were the Moon’s rhythms, mostly that its phases repeat every 29.5 days. This week we cover the rhythms of the universe!

It's widely misunderstood where in the heavens the sun sits at the time of the solstice. Traditionally it was the zodiacal sign of Cancer, hence "Tropic of Cancer" as the earthly place where you’d see the midday sun standing straight overhead. But despite the lingering name, the solstitial sun drifted out of Cancer and into Gemini two thousand years ago. This week: a special solstice.

It’s often hard to separate coincidence from correspondence, like the 11-year sunspot cycle. Powerful solar storms must affect us, but there are thousands of potential rhythms from political events to earthquakes we could try to match up with it. It's challenging to know which are related and which are merely the mischief caused by the law of averages.

Starting next week, the nearest star to the Moon will be the bluest of them all, which is Virgo’s brightest star, Spica. Hear why Spica, one of the brightest objects in the constellation of Virgo, is one of the 20 brightest stars in the night sky.

It’s time to have some serious sky-fun. This coming Tuesday and Wednesday evening, the nearest celestial bodies will perform some tight gymnastics for our enjoyment. You don’t even need unpolluted country skies — city streets will work for this one.

The universe’s four forces are identical everywhere. So, any physical truth that applies to our galaxy must be identical everywhere else and throughout all of time. In the 1930s, future Nobel-winner Paul Dirac wondered whether time has always passed the same way and whether light’s speed is truly a constant. But despite such doubts, the cosmos certainly appears to be the same always and everywhere. This week we’ll explore where the universe is heading.

By this summer we will see the brilliant star Vega in all its glory. This week hear how Vega, appearing slightly blue-white, is the sky's reference point for the magnitude system.