The Red Planet and the Ringed Planet are extremely close right now.
Have you ever seen Saturn's rings? Or caught a glimpse of Mars, our bright red neighbor?
If you've been up before dawn this month, you may have noticed some particularly bright celestial bodies glowing in the southeastern portion of the sky. But they're actually the planets Mars, Saturn, and Jupiter, as well as the star Antares in the constellation of Scorpius. Throughout April and into May, Saturn and Mars will stay extremely close together. Astronomers call this a conjunction, and it's one’s worth waking early for.
Why Are Mars and Saturn so Close to Each Other?
In reality, these planets are not close at all — it's merely a line of sight phenomena as seen from Earth. All the planets in the solar system are orbiting the Sun at different speeds, so our view of the planets is constantly changing. Mars is around 102 million miles from Earth (and the closest planet to Earth) while Saturn is much farther out at 746 million miles.
To see exactly what's going on in the solar system right now, take a look at The Planets Today, which shows an amazing live view of the solar system. Mars takes 687 Earth days (almost two Earth years) to orbit the Sun, while much slower Saturn takes 29 Earth years to complete one Saturn year.
In the first few days of April this year, Mars appeared to 'lap' Saturn, as they were just a degree apart in the night sky. They're still very close, but not for long.
When Is the Best Time to Look for Saturn?
With Mars now moving away from Saturn, don't waste any time if you want to catch them in this celestial chase. Look low on the southeast horizon about an hour before sunrise throughout the month of April. Naked eye observation is fine, but if you do have binoculars or a small telescope, both planets are easily visible. As a bonus, with any telescope you will see Saturn's beautiful rings as well as its giant moon, Titan.
When Is the Best Time to Look for Mars?
Although you can look at Mars perfectly right now, the planet will be brighter than it's been for 15 years in late June and early July of 2018. That's when the planet comes into 'opposition,' meaning the Earth is directly between the Sun and Mars, so the planet's disk will be fully lit. This opposition is extra special, however, because Mars hasn't been this close to the Sun since 2003, meaning it will be even brighter than usual. In fact, it will shine a brilliant red, and be brighter even than Venus.
What's the Other Bright Light Above Mars and Saturn?
High in the southwestern sky just before sunrise in April is the brighter fifth planet, Jupiter. If you have any kind of binoculars, even a small pair, point them at this giant planet and you'll see its four largest moons: Io, Europa, Ganymede, and Callisto. Between Saturn and Jupiter, stargazers can also spot the famously red supergiant star, Antares, in the constellation of Scorpius. This star is frequently confused with Mars, so look closely. With Saturn in the middle, Mars is on the left, and Antares is on the right.
When Is the Next Time Mars and Saturn Will Conjoin?
Because Saturn is so slow-moving, and Mars take about twice as long to orbit the Sun as Earth does, Mars appears to lap Saturn — as seen from Earth — once every two years or so. The last conjunction was on August 25, 2016, and the next will occur on March 31, 2020, with Mars and Saturn appearing to pass less than a degree apart.