Mars, Neptune Embrace On New Year’s Eve / Aurora With Your Bubbly?

This map shows the sky facing southwest around nightfall on Saturday evening, December 31st. Mars is located about a fist (at arm’s length) to the upper left of Venus in central Aquarius. Binoculars and small telescopes will show Neptune next to Mars in a very close conjunction. Joining the scene is a delicate crescent Moon lower down in the west. What a beautiful way to end the year! Map: Bob King; source: Stellarium

Mars won’t have to look hard to find a dance partner for the New Year’s Eve ball. It can only be Neptune. Beautiful, unavoidable Neptune. The Red Planet sashays up to the Blue Planet on Saturday evening Dec. 31, and you can see the sparkling couple using a pair of 50mm (or larger) binoculars or a small telescope. They’ll be close. If you’re reading this from London, the two will be ⅓° apart around 6 p.m. local time. From the U.S. Midwest that shrinks to just 0.2°, and from Honolulu to 0.016° or just 1 arc minute.

Binocular simulation of Mars and Neptune viewed from three cities around 6 p.m. local time on December 31st. The planets’ separation will be 0.36° (London), 0.25° (New York City) and 0.15° (San Francisco). North is at upper right. Maps: Bob King; source: Stellarium

The reason the two planets get closer as you travel west is that time is passing, and Mars is moving fairly quickly across the sky. It gets dark first in London, then 6 hours later in Chicago. During that time, Mars keeps chugging to the east, getting closer to Neptune with every tick of the clock. If you keep a close watch on Mars, comparing it’s position to the surrounding stars, you can actually see it move night to night this time of year with just your eyes alone.

The two planets will be closest around 12:45 a.m. Central Standard Time on Jan. 1. Unfortunately, they will have set for the continental U.S. by that hour — but not in Hawaii. So if you’ve wisely planned a trip there over New Year’s, you’ll get to see the planets exceptionally close together.

Mars and Neptune just one arc minute or 0.016° apart as viewed from Honolulu on Dec. 31 around 7-8 p.m. local time. The simulated magnification here is about 350-400x! That tells you how amazingly close these two planets will be. If you have an 8-inch or larger telescope, look for Neptune’s brightest moon, Triton, a dim, 14th magnitude “star” just southwest of the planet. Map: Bob King; source: Stellarium

Of course, we know that Neptune and Mars will only appear to be slow dancing because we see them along the same line of sight, like lining up your thumb with a distant mountain. In reality, Mars hovers 150 million miles from Earth that night and Neptune 2.8 billion. The distance between them is a mind-numbing 2,675,000,000 miles! Truth to tell, this couple is anything but close.

The best time to catch the event is at nightfall or around 6 p.m.- 7:30 p.m. local time. First, find outrageously bright Venus in the southwestern sky and then look about one fist held at arm’s length above and to the left of that planet to spot Mars. Mars isn’t nearly as bright as Venus, but it’s the brightest “star” in the area and unmistakably red in color. Next, point your binoculars at Mars, carefully focus until it’s as tiny a point as possible and then look immediately to the upper left of the planet for a dim twinkle of light. That’s Neptune. From Hawaii, Neptune will be to Mars’ upper right and exceptionally close. Focus is key, so make sure stars look sharp before attempting to see Neptune.

Mars and Neptune are far apart in terms of size, temperature, and composition, but you know what they say — when it comes to couples, opposites attract. Source: Lunar and Planetary Institute

It’s fun to consider how different Mars and Neptune are. One’s a small planet just twice the size of our moon with a cold, dry, desert-like environment and an atmosphere so thin that any exposed water would boil away in seconds.  Its dance partner is nearly four times the size of Earth with a vast, deep atmosphere tinted blue from icy-cold methane gas. Deep beneath those aqua clouds churns a slushy, high-pressure mix of water, methane and ammonia ices.

Here’s lookin’ at ya, baby. This photo of a hole directly facing Earth in the sun’s corona or outer atmosphere was taken on Dec. 28 by NASA’s Solar Dynamics Observatory. Particles streaming freely from the hole may fire up auroras when they arrive at Earth tomorrow afternoon. Credit: NASA

If you’ve never seen the solar system’s most distant planet, grab the chance New Year’s Eve night before you down too much bubbly. Speaking of which, skywatchers in northern Europe, Canada and the northern U.S. should be on the watch for aurora that night. A coronal hole in the sun’s atmosphere recently sent a spray of high speed particles our way that’s expected to arrive tomorrow afternoon and possibly fire up a G1 geomagnetic storm through the early evening hours. The moon won’t be a bother, so be sure to cast a glance northward. You’ll be looking for a low, green-hued arc and possibly some faint, feathery rays.

10 Responses

  1. Peter

    Hey Bob, Thanks for another great “heads up”.

    One thing…you forgot three more zero’s in the billions of miles between mars and neptune 🙂

    1. astrobob

      Happy New Year, Marshall. About the video: I don’t buy the lightning explanation for Martian craters and canyons, etc. because there’s no proof of it — just surmise — and meteoric impact and tectonic forces are far more common and proven ways to explain the structures. I agree that lighting is one hypothesis that could explain chondrule formation, but there are other ideas out there as well. None has been proven yet definitively — I really wish we had a definitive answer on that one!

      1. caralex

        It’s just more pseudoscience from the electric universe crowd, Bob. As you say, there’s no evidence for it. If they’re so convinced they’re right, how is it that they can never produce one single example of a lightning strike forming a crater here, in the present?

        1. astrobob

          Why is the “electric universe” belief so pervasive? I’ve got to believe someone must be making money off of it otherwise I don’t understand why it persists.

          1. astrobob

            Hi BC,
            Sorry if it seems so. None implied. I’m just baffled. It’s not an end-of-world idea and it lacks proof, so I’m just curious from a social point of view. What’s your opinion?

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