You are here

Jupiter at Opposition

March 7, 2016

The king of the planets is putting in an appearance that befits its status right now. It’s at a point known as opposition. It lines up opposite the Sun in our sky, so it rises around sunset and is in view all night. The planet is also closest to Earth for the year, so it shines brightest.

Jupiter is the biggest planet in the entire solar system. It’s about 11 times Earth’s diameter, and more than 300 times its mass. In fact, it’s more massive than all the other planets and moons in the solar system combined.

Jupiter probably grew so big through a two-step formation process.

In the first step, small bits of rock and ice stuck together to form larger and larger clumps. Jupiter was far enough out that solar heat couldn’t vaporize the ices and some other solid materials that encircled the Sun. That allowed the growing clumps to get even bigger, and many of them merged to form what became Jupiter’s core.

The core quickly reached several times the mass of Earth. As it did so, the second step kicked in. The gravity of the big, heavy proto-Jupiter pulled in vast amounts of gas left over from the Sun’s birth. That gave the planet a thick envelope of hydrogen and helium around the core — and helped Jupiter grow to giant proportions.

Look for this massive planet all night long. It’s low in the east as night falls and arcs high across the south around midnight. It looks like a brilliant cream-colored star, so it’s hard to miss.

More about Jupiter tomorrow.

Script by Damond Benningfield

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.