What To Know About the 2018 Super Blue Blood Moon

by AMNH on Jan 30, 2018 5:02 pm

Moon rises over snowcapped mountains and evergreen trees.

A Blood Moon is a lunar eclipse, which occurs when the Moon passes into Earth’s shadow.
Courtesy of Denali National Park and Preserver/Flickr

As the Moon begins to set in the morning hours of January 31, 2018—between 5:51 and 7 am Eastern Standard Time, to be precise—people in New York City will have the chance to glimpse a lunar event that hasn’t happened in both hemispheres for more than 150 years: a so-called Super Blue Blood Moon.

The visualization below shows the Super Blue Blood Moon’s movements from space.

The Super Blue Blood Moon

Published January 29, 2018

[BEETHOVEN'S MOONLIGHT SONATA PLAYS]

[A visualization shows the Earth in space, as the Moon traverses its orbit, moving from right to left on the screen.]

[TEXT: On Wednesday, January 31, 2018, the Moon will pass through Earth's shadow, in a rare lunar configuration last seen more than 150 years ago.]

[TEXT: The Super Blue Blood Moon]

[TEXT: Super—the Moon is near perigee, the closest point in its orbit around Earth.]

[TEXT: Blue—the second full moon in a calendar month.]

[TEXT: Blood—apparent orange-red shading on the Moon's disk caused by sunlight refracted into Earth's shadow.]

[As the Moon passes into Earth's shadow, the visualization freezes. An inset image appears of the Moon during a lunar eclipse. A reddish-orange gradation tints the moon's surface.]

[The inset fades out, the Earth resumes rotating, and the Moon continues moving in its orbit.]

[American Museum of Natural History logo and credits appear.]

What is it? It’s actually three different phenomena. The first, a Super Moon, when the moon is at or near perigee syzygy, happens when the Moon is at the closest point in its orbit around the Earth. Depending on your location, the Moon may appear slightly larger in the sky than it would on other nights.

Next, a Blue Moon is the second full moon of the month—in this case, a full Moon squeaking in at the last possible moment in January.

And finally, a Blood Moon is another term for a lunar eclipse, when the Moon passes into Earth’s shadow and appears to darken and turn a shade somewhere between deep red to rusty brown. Of the three, this is perhaps most exciting to regular skywatchers, since the last total lunar eclipse took place more than two years ago, in September 2015.

Unfortunately for the East Coast, the best places to watch the lunar eclipse will be in Alaska and Hawaii, according to Museum astrophysicist Jackie Faherty. But that’s not to say you can’t still enjoy the other two parts of the lunar trifecta—and, good news: you don’t even have to get up early.

“You can see the Super [Moon] part, and the fact that it’s a Blue Moon, by just walking outside on January 31 and looking up,” she says. “A full Moon always rises right around when the Sun sets, and then sets right around when the Sun rises. As a result, you’ve got a whole night to go outside and look at the Moon.”

For more tips from Faherty, including how to take pictures of tonight’s Super Blue Blood Moon, listen to the complete interview in the latest episode of our podcast Science@AMNH. Subscribe on iTunes, Soundcloud, or wherever you get your podcasts.

Podcast: Download | RSS | iTunes (19:43, 19.3 MB)

2018 Super Blue Blood Moon: Facts and Tips with Astrophysicist Jackie Faherty — Podcast Transcript

NARRATOR: You’re listening to Science at AMNH, the podcast of the American Museum of Natural History.

On January 31^,2018, a trifecta of lunar events will cause what’s being dubbed a “Super Blue Blood Moon.” Museum astrophysicist Jackie Faherty explains what causes this phenomenon, provides us some with some viewing tips, and tells us about other cosmic events we have to look forward to in 2018.

INTERVIEWER: Hi Jackie, thank you so much for sitting down with us today.

FAHERTY: Happy to be here.

INTERVIEWER: So I understand we have a really exciting astronomical event coming up, can you let us know what a super blue blood moon is?

FAHERTY: So a super blue blood moon—which I feel like this may be the first time it's ever been hashtagged like this ever—is the trifecta of three different labelled phenomena with the moon. One is a super moon, which means that the moon is in its orbit around the Earth at, in the current orbit, ninety percent of its closest possible distance. Terrible definition, it was not defined by astronomers, it was defined by an astrologer and so astronomers aren't super happy with the term, but people love the word “super” and so it really catches the public eye. So super moon will be happening, which means it's going to be a particularly close full moon, and then the blue moon is because we label the second full moon in a given month a blue moon so that's all it is. We had a full moon on January first, on the first day of the year we had a new year full moon, and this is the second one. And so blue moon.

Then Blood Moon comes from the other way the public has of popularly defining what they see, and that is a technical term for it is a total lunar eclipse. So it's when the moon passes into the Earth's shadow and darkens and then depending on what's in the Earth's atmosphere, there is still some light that gets through and gets to the moon. But that's really just the light the last bits of light that are getting by at sunrises and sunsets. And so that's the light that can make it to the moon and then back to us, So it's a very pretty idea that when you're staring at a Blood Moon or a total lunar eclipse, what you're actually looking at, is a reflection of all of the sunrises and sunsets that are going on across the earth.

So hence combine all of them super blue Blood Moon. You can rearrange those words however you like, you don't have to call it that way, but people have really grabbed onto super blue blood.

INTERVIEWER: And when is this one going to be happening and where is the best place for people to watch it?

FAHERTY: So it happens on January 31^st, the last day of the month. And the best places to watch it are—that's a question really about the earth, since we live in a really big earth and the moon is only eclipsed for a short period of time. So as a result not the whole globe gets to see the phenomenon. The best places are going to be the far western part of the US, and that actually means Alaska and Hawaii. The continental US won't actually get to see the whole thing because the moon will be setting while the Eclipse is either beginning or ongoing and otherwise if you were in Australia or New Zealand or parts of Asia those are great spots because you're going to see the whole thing. So the other side of the hemisphere, the southern hemisphere and the eastern hemisphere, are far better off than we are. That's not to say it's not still fun to go outside and look at the full moon. So you can see the super part, and the fact that it's a blue moon by just looking at it very easily by just walking outside on January 31^st and looking up. A full moon always rises right around when the Sun sets and then sets right around when the Sun rises, so as a result you’ve got a whole night to go outside and look at the moon. But the Blood Moon portion of it for those of us on the far east side of the US and actually across the US—that all is going to happen for us in the small hours of the morning when the moon is getting ready to set, and the Sun is going to rise so you'd have to get up early. But then you get to see it happening.

INTERVIEWER: And is there somewhere that people can look up what the best time is to see the Super Blue Blood Moon for where they’re located?

FAHERTY: Yeah, I have a favorite website and it's time and date, and that gives you lots of information. So timeanddate.com gives you lots of information about eclipses as well as sunrises and moon rises, and many different things about the Earth-Sun-Moon system that you might be curious about. And so, you can look up on that site giving you a particular location on the planet, and it'll tell you exact times. NASA has a couple of sites that are really good as well. They give you more details than you thought you'd ever want to know about eclipses, so you can also look on NASA's various eclipse sites.

INTERVIEWER: Do you have any tips for viewers who might want to photograph this event?

FAHERTY: Photographing the moon is very, very tricky. The best thing I can recommend is finding a small telescope, and shooting the moon through the small telescope. I used to have an adapter for my digital camera—so I had a DSLR—and the there's adapting pieces that can screw the back of your camera on to a onto the backside of a small telescope, nothing big, and you can get gorgeous images of the moon that way. Otherwise, the moon is not close to us, and so trying to take a snapshot with your iPhone is going to be a little bit tricky. Not impossible. So I have in my office actually a picture of a total lunar eclipse in the middle of occurring, and the thing that's really beautifully captured with that—and that's just with a standard camera—is the color. So if you're interested in doing this you should think about exposure times, where you want to be set up, you’ll need a tripod, you'll want to get a remote so that you can open and close the shutter on your own so that it stays very stable if that's what you want. But you're not going to see the structure of the moon. You'd see the structure of the moon if you get that adapter and you mount the base of your camera onto a telescope.

INTERVIEWER: When was the last time we had a super Blue Blood Moon?

FAHERTY: Oh such a good question and this is a very controversial question right now actually. So here's what happened—this is why the question of how when was the last time it occurred is currently vaguely controversial. So one argument is 150 years ago, 150 years ago was the last time we had a blue moon and a Blood Moon. So a second full moon that turns out to be a lunar eclipse. The Super Moon part of it, no one ever really talks about. So you get super moon so often and they're so broadly decided on, let's just go with the last time we had a blueblood moon. And 150 years ago there was one, but also in December of 1982, there was also a total lunar eclipse that had two full moons in that December. However—here's the odd part—in Europe, time had changed when the eclipse happened in the US. It hadn't and so Europe would have had a blue moon, but in the U.S., the time had changed already and so as a result that wouldn't have been considered a blue moon for a different part of the planet. So you know, it's how you define it, so for those of us here in the northern hemisphere it's been 150 years, but if you're in Europe then it's been a shorter amount of time, if you want to go by that definition.

INTERVIEWER: So we've all heard the expression “once in a blue moon”, but how rare are blue moons?

FAHERTY: Blue moons are not rare at all. And I like to try and give a definition to the what we should really mean when we say “rare.” So I like to think of rare events, whenever that term comes up in astronomy, as something that I'm only going to see once or maybe twice in my lifetime. So Halley's Comet, which has an orbit of something on the order of 70 to 80 years, I would consider that a rare event for a human to witness. The transit of Venus, which comes in pairs which are seven years apart, seven-ish years apart, and then it's a century or so between them. I would consider that a rare event. A blue moon occurs once every two and a half to three years, so I would not call blue moons rare at all. I'm not exactly sure how that caught on as a rare event, but certainly it's a good example of a misplaced description of something.

INTERVIEWER: How do astronomers predict when these kinds of events will happen?

FAHERTY: The way that we understand these is also a question of how the history of astronomy has developed historically. And that is, we understand very, very well the exact positions that the earth the Sun and the moon are in. So you know exactly how far away the moon is from the earth, and we know how far away the Sun is, we know the inclination of their orbits, so how far inclined they are from each other, and we know they're eccentricity. And once you have that info, then you can put it all together and look for intersections of orbits say for when you're going to get an alignment. And it's amazing to see it happen, but the planets follow very, very fundamental laws of physics, and so orbital dynamics tell you when this is going to happen. It's science and it works.

INTERVIEWER: What other lunar phenomena do you recommend people keep an eye out for?

FAHERTY: So I love watching the moon. And one thing that I'll say, I think is the most underrated phenomenon that we can see so easily is witnessing a full moon rise and a full moon set. Or, in general a moon rise or a moon set. Moon rises and moon sets aren't the things you hear about in the movies, as like they drove off into the moon set or they drove off into the moon rise—that's not what people think about. They think of the sunrise and the sunset—It's the big light bulb in our sky. But the moon is arrival of the Sun and it's brilliance, and in in the kinds of like creativity that it inspires in people. And the moment that it shows up in your sky, it changes the light around it and causes its own beautiful little rise moment similar to how sunrises are so beautiful, and sunsets. So I try and prioritize watching, whenever I can, the moonrise and then trying to prioritize a moon set as well, if possible, because it reminds you of this other object that's so prominent in our sky, and that people don't necessarily pay attention to. So that’d be if I recommend anything for people, is to look at when moon rises and moon sets happen. Find the direction that you need to be looking in so that you make sure there's no tall building in your way, and watch them. They're great to watch.

But otherwise, some fun things to see with the moon is, the way that the moon moves is different than the way that the stars move. As the planets also move in a different way than the stars move—meaning rising and setting through the night. You will see that the moon will be in a very different position every night. So whereas the stars don't move, the moon, we're actually watching it move in its orbit so that's a fun thing to watch. It's part of why we can get phenomena like a planet and a moon get closer to each other and then farther and farther away as the nights go on. So I would recommend monitoring where the moon is in relation to stars. And then the easy things to do with the moon is just try and identify any structure that you see. Look at the craters, look at the Mare, look at the Highlands, they should trigger all sorts of things in your imagination. You can make out a lot of it with your naked eye, so just look at the moon.

INTERVIEWER: What other astronomical events do we have to look forward to in 2018?

FAHERTY: For the globe, there's going to be some other eclipses. There's going to be a partial solar eclipse on February 15^th, and then later in the year there's going to be a total lunar eclipse that will be visible on July 27^th, 2018. Unfortunately for us in the U.S., we're out of the visibility zone for that, but for our friends in South America, or Africa, Australia, they'll get some nice eclipses viewing. Every year it's going to be different hemisphere-favoring Eclipse moments. So it's not necessarily our year in the northern hemisphere, but other things you could look forward to looking at; on March 7th to 8^th, we're going to have what's being called a parade of planets or a planet parade. People like to look for fancy names for the exciting things that might happen with things in the sky. So in the case of the March 7th to 8th visibility you'll—and you should watch the sky up until this moment—so what you'll see is Saturn, Mars, and Jupiter in a nice little line, the moon kind of mid distance between Mars and Jupiter, and the star Antares, which is this beautiful red star in the constellation Scorpio the scorpion and it's red, and oftentimes it can get mistaken for Mars. But it is right around the time of March 7th to 8^th, be outside and look for this line of planets, which is always fun to see.

Other things are, every year the Earth passes through similar trails of comets that have long since been here, and that caused meteor showers that are always fun to look at. My particularly favorite is the Perseids which happens in the summer, so right around mid-August or so, August 12th August 13^th, you'll get a peak in fireballs radiating from the constellation Perseus. And why that's so fun is because it's this summer and you can be outside and you get to look around and then at the sky, and see things flying around which is great excuse to be outside looking up.

So otherwise, the exciting things that are happening in astronomy in science there are some big things happening this year. The most exciting of which, for me, and maybe for all astronomers though I haven't taken a poll on this, is on April 25th of this year—and this was only announced very, very recently—that the Gaia Catalog, which is this spacecraft that's been imaging the entire sky and has measured distances to stars and how they move and how they vary, and on April 25th it will reveal its second release of a catalog, which will contain one and a half billion distances to stars. Which is an unprecedented number. And it will also have six million radial velocities meeting this difficult to measure motion through the galaxies that stars have. As a result, we are going to have a completely different view of the motions, of the history of our galaxy, of the structure of our galaxy, and we will likely redefine many if not all laws of the physical nature of stars. So look forward to April 25^th, 2018.

And otherwise there's two really important launches that are slated to occur this year. So in March of this year, the TESS telescope— TESS is an acronym for the transiting exoplanet survey satellite, and TESS is going to be imaging the whole sky and looking for transiting exoplanets which pass in front of their host star. And part of why this is going to be such an amazing new survey is, it's a huge step from the Kepler spacecraft which threw at us thousands of exoplanets, and it'll be able to look for planets around our lowest mass stars, where we see the most number of stars. So it's going to be really exciting for exoplanet science.

And then the other one, which is slated to launch in October of this year, is the James Webb Space Telescope. This is the successor of the Hubble Space Telescope. It's a bit different than Hubble in that it's not going to be a serviceable telescope, but it's a phenomenal telescope observatory, with instruments that will let us do everything from investigate the origins of the universe in general, for extra to galactic science, to study to a level that we just are not capable of right now, the atmospheres of worlds outside of our own solar system. So this is going to be a big year for the movement forward of science in general. Astronomy's big year forward.

And people should be excited about 2018. One thing I just want to note before we go, when I was asked to give my prediction for what I think is the most exciting thing that's going to happen in 2018, and I said I think this is going to be the year of the Milky Way. So that's what I would end on, that I think 2018 will be remembered as the year of the Milky Way. Most especially, the Gaia telescope giving us all of these parallax's and velocities for an unprecedented number of stars, so let's enjoy our year of the Milky Way.

INTERVIEWER: And we'll kick it off with our super blue blood moon which people can watch on January 31^st. Thank you so much.

FAHERTY: Happy to help.