[upbeat music]
Preston: "What's Up" for January?
Getting close to the Sun,
some easy outer-planet spotting,
and a chance to catch quick-moving Mercury.
The new year begins with planet Earth
at the closest point in its orbit around the Sun
called perihelion on January 2nd.
Now you may have learned in school
that Earth orbits a certain distance from the Sun
and then its orbit is nearly circular.
The average distance from Earth to the Sun
is called an astronomical unit.
But since our orbit is not a perfect circle
it means sometimes we're a bit closer to the Sun
and sometimes farther away.
In fact, our distance from the Sun
varies by around 3 million miles
over the course of the year.
That's nearly 13 times the distance from Earth to the Moon.
At perihelion Earth will be around 91 1/2 million miles
from our local star.
And when we were at the farthest point it's called aphelion.
That happens this year on July 5th
when we'll be around 94 1/2 million miles away.
[whoosh sound]
If you have access to binoculars or a telescope
then you might wanna haul them out on January 20th.
Which offers an easy opportunity to view the planet Uranus.
The distant outer planet is too faint
for most of us to see with the unaided eye.
And it can be tough to locate in the sky
without a computer-guided telescope.
But on the 20th Uranus will be located
right between the Moon and Mars.
That evening find the crescent Moon and the Red Planet
in the couple of hours after it gets dark.
Scan your way over from Mars toward the Moon,
and you should be able to find
the faint bluish disk of Uranus.
Along with Neptune, Uranus has only been visited
by a single spacecraft so far,
that being NASA's Voyager 2 more than 30 years ago.
And as more recent telescope views
have revealed the active atmosphere
beneath its hazy blue exterior,
scientists are eager to one day return for a closer look.
[whoosh sound]
The last two weeks of January
offer opportunities to catch a glimpse
of the fast moving planet Mercury.
Look for the innermost planet of our solar system
just after sunset beginning mid-month.
You'll need a clear view toward the West
as Mercury will appear just a few degrees above the horizon
about the width of your outstretched fist.
This little planet orbits much closer to the Sun than Earth.
Meaning it also goes around the Sun much faster
completing its "year" in about a quarter of the time
it takes Earth to go around once.
And that's why we have a chance to view Mercury
in the sky every three months or so,
as it appears to dark back and forth
from one side of the Sun to the other.
But Mercury never gets too far away
from the Sun from our vantage point.
And thus, we only see the little planet
just before or after the Sun rises or sets.
Last visited by NASA MESSENGER spacecraft
which ended its mission in 2015,
Mercury is slated to see a new visitor in orbit in 2025,
when the joint European and Japanese mission
BepiColombo arrives there.
[whoosh sound]
Here are the phases of the Moon for January.
You can catch up on all of NASA's missions
to explore the solar system and beyond at nasa.gov.
I'm Preston Dyches from NASA's Jet Propulsion Laboratory,
and that's "What's Up" for this month.
[upbeat music]