What are some Sky Watching Highlights in January 2021? Mark Earth’s approach to the Sun for the year, called the Perihelion at the beginning of the month, then spotted some insidious planets: Uranus January 20th and the second half of Wednesday.
Video transcript:
What’s up for January? Getting closer to the sun, spotting some simple outer-planet, and the chance to catch a fast-moving Mercury.
The new year begins on January 2nd at a location close to the Earth’s orbit around the Sun. Now you may have learned in school that the earth orbits at a certain distance from the sun and its orbit is almost round. The average distance from Earth to the Sun is called the astronomical unit, but our orbit is not a perfect circle, so it means that we are a little closer to the Sun, and sometimes farther away.
In fact, during the year, our distance from the sun changes by about 3 million miles. It is about 13 times the distance of the moon from the earth.
At perihelion, Earth would be about 91.5 million miles away from our local star. And when we are at the farthest stage it is called “Afflean”. It happens on July 5th this year, when we’re about 94.5 million miles away.
If you have access to binoculars or telescopes, then you can take them out on January 20, which gives an easy opportunity to see the planet Uranus. The distant, outer planet is too obscure for most of us to see with the naked eye, and difficult to locate in the sky without a computer-guided telescope. But on the 20th Uranus will be located between the Moon and Ni Mars. That evening, find the crescent moon and the red planet within a few hours of darkening. Scan yourself from Mars to the moon, and you should be able to find the stupid, blue disk of Uranus.
With Neptune, Uranus has been visited by the same spacecraft so far, that is NASA‘Voyager 2’, more than 30 years ago. And as more recent telescopic scenes reveal an active atmosphere beneath its dim, blue exterior, scientists are eager to return one day to take a closer look.
The last two weeks of January provide opportunities to see glimpses of the fast-moving planet Mercury. Look at the planets in our solar system just after sunset in the middle of the month. You will need a clear view to the west, as Mercury will appear slightly above the horizon (about the width of your outstretched fist).
This tiny planet orbits the Sun much closer than the Earth, meaning it completes its “year” in about a quarter of the time it takes for the Earth to orbit once. And that’s why we get to see Mercury in the sky every three months or so, as it appears to move back and forth from one side of the sun to the other. But Mercury is never too far from the Sun from our point of view, and this is how we see small planets just before or shortly after the sun rises.
The last visit was by NASA’s Messenger spacecraft, which completed its mission in 2015, while Mercury is preparing to see a new visitor into orbit in 2025, when the joint European and Japanese mission Bepi Colombo arrives.
Here are the phases of the moon for January.
You can get all of NASA’s missions to explore the solar system and beyond on NASA.gov. I’m Preston Dutch from NASA’s Jet Propulsion Laboratory and what it is for this month.
