You are here

Moon and Saturn

February 2, 2016

The Moon has a couple of bright companions before dawn tomorrow. The planet Saturn looks like a golden star just below the Moon. And the true star Antares is to their lower right, shining bright orange.

Saturn is famous for its brilliant rings. And two space telescopes discovered a new ring that’s the biggest in the solar system.

Both telescopes are sensitive to the infrared — wavelengths of light that are longer than those visible to the human eye. In 2009, Spitzer Space Telescope detected the feeble infrared glow of dust grains far outside Saturn’s visible rings. These tiny particles are hundreds of degrees below zero, but sunlight warms them enough to make them glow in the infrared.

And more recently, another infrared-seeking spacecraft, known as WISE, found that the ring is even larger than first thought. According to the new measurements, the ring’s inner edge is about four million miles from Saturn, while the outer edge is 10 million miles from the planet. If Saturn were a basketball at the center of an NBA court, the outer edge of the new ring would span the entire court.

The ring probably gets its dust from collisions between comets and some of Saturn’s distant moons. The impacts kick up dust and debris that go into orbit around Saturn. This debris produces a faint but enormous ring, far beyond the much brighter rings that make Saturn one of the most beautiful sights in the solar system.

Tomorrow: lunar landing.

Script by Ken Croswell, Copyright 2015


Get Premium Audio

Listen to today's episode of StarDate on the web the same day it airs in high-quality streaming audio without any extra ads or announcements. Choose a $8 one-month pass, or listen every day for a year for just $30.