Posted on by Fraser Cain

Why is the Moon Leaving Us?

Why is the Moon Leaving Us?

Goodbye Moon. Every year, the Moon slips a few centimeters away from us, slowing down our day. Why is the Moon drifting away from us, and how long will it take before the Earth and the Moon are tidally locked to each other?

We had a good run, us and the Moon. Grab your special edition NASA space tissues because today we’re embarking on a tale of orbital companionship, childhood sweethearts and heartache.

You could say we came from the same part of town. A long time ago the Mars-sized object Theia, collided with the Earth and the Moon was formed out of the debris from the collision.

We grew up together. Counting from the very beginning, this relationship has lasted for 4.5 billion years. We had some good times. Some bad times. Gravitationally linked, arm in arm, inside our solar family sedan traversing the galaxy.

But now, tragedy. The Moon, OUR Moon, is moving on to brighter horizons. We used to be much closer when we were younger and time seemed to fly by much faster. In fact, 620 million years ago, a day was only 21 hours long. Now they’ve dragged out to 24 hours and they’re just getting longer, and the Moon is already at a average distance of 384,400 km. It almost feels too far away.

If we think back far enough to when we were kids, there was a time when a day was just 2 – 3 hours long, and the Moon was much closer. It seemed like we did everything together back then. But just like people, massive hunks of rock and materials flying through space change, and their relationships change as well.

Our therapist told us it wasn’t a good idea to get caught up on minutiae, but we’ve done some sciencing using the retroreflector experiments placed by Apollo astronauts, and it looks as though the Moon has always had one foot out the door.

Today it’s drifting away at 1-2 cm/year. Such heartache! We just thought it seemed like the days were longer, but it’s not just an emotional effect of seeing our longtime friend leaving us, there’s a real physical change happening. Our days are getting 1/500th of a second longer every century.

I can’t help but blame myself. If only we knew why. Did the Moon find someone new? Someone more attractive? Was it that trollop Venus, the hottest planet in the whole solar system? It’s really just a natural progression. It’s nature. It’s gravity and tidal forces.

And no, that’s not a metaphor. The Earth and the Moon pull at each other with their gravity. Their shapes get distorted and the pull of this tidal force creates a bulge. The Earth has a bulge facing towards the Moon, and the Moon has a more significant bulge towards the Earth.

A series of photos combined to show the rise of the July 22, 2013 ‘super’ full moon over the Rocky Mountains, shot near Vail, Colorado, at 10,000ft above sea level in the White River National Forest. Moon images are approximately 200 seconds apart. Credit and copyright: Cory Schmitz
A series of photos combined to show the rise of the July 22, 2013 ‘super’ full moon over the Rocky Mountains, shot near Vail, Colorado, at 10,000ft above sea level in the White River National Forest. Moon images are approximately 200 seconds apart. Credit and copyright: Cory Schmitz

These bulges act like handles for gravity, which slows down their rotation. The process allowed the Earth’s gravity to slow the Moon to a stop billions of years ago. The Moon is still working on the Earth to change its ways, but it’ll be a long time before we become tidally locked to the Moon.

This slowing rotation means energy is lost by the Earth. This energy is transferred to the Moon which is speeding up, and as we’ve talked about in previous episodes the faster something orbits, the further and further it’s becomes from the object it’s orbiting.

Will it ever end? We’re so attached, it seems like it’ll take forever to figure out who’s stuff belongs to who and who gets the dog. Fear not, there is an end in sight. 50 billion years from now, 45 billion years after the Sun has grown weary of our shenanigans and become a red giant, when the days have slowed to be 45 hours long, the Moon will consider itself all moved into its brand new apartment ready to start its new life.

What about the neighbors down the street? How are the other orbital relationships faring. I know there’s a lot of poly-moon-amory taking place out there in the Solar System. We’re not the only ones with Moons tidally locked. There’s Phobos and Deimos to Mars, many of the moons of Jupiter and Saturn are, and Pluto and Charon are even tidally locked to each other, forever. Now’s that’s real commitment. So, in the end. The lesson here is people and planets change. The Moon just needs its space, but it still wants to be friends.

What do you think? If you were writing a space opera about the Earth and the Moon break-up, what was it that finally came between them? Tell us in the comments below.

Posted on by Bob King

Potential Weekend Meteor Shower Will Pelt the Moon Too!

the shaded or speckled area indicates where May Camelopardalids can stoke the lunar surface. telescopic observers will want to point their telescopes to the shaded dark area at the top right of the lunar disk.

If the hoped-for meteor blast materializes this Friday night / Saturday morning (May 23-24) Earth won’t be the only world getting peppered with debris strewn by comet 209P/LINEAR. The moon will zoom through the comet’s dusty filaments in tandem with us.

Bill Cooke, lead for NASA’s Meteoroid Environment Office, alerts skywatchers to the possibility of lunar meteorite impacts starting around 9:30 p.m. CDT Friday night through 6 a.m. CDT (2:30-11 UTC) Saturday morning with a peak around 1-3 a.m. CDT (6-8 UTC). 

While western hemisphere observers will be in the best location, these times indicate that European and African skywatchers might also get a taste of the action around the start of the lunar shower. And while South America is too far south for viewing the Earth-directed Camelopardalids, the moon will be in a good position to have a go at lunar meteor hunting. Find your moonrise time HERE.

Earlier lunar impact on the earthlit portion of the moon. Credit: NASA
Earlier lunar impact on the earthlit portion of the moon recorded by video camera. Credit: NASA

The thick crescent moon will be well-placed around peak viewing time for East Coast skywatchers, shining above Venus in the eastern sky near the start of morning twilight. For the Midwest, the moon will just be rising at that hour, while skywatchers living in the western half of the country will have to wait until after maximum for a look:

“Anyone in the U.S. should monitor the moon until dawn,” said Cooke, who estimates that impacts might shine briefly at magnitude +8-9.

Any meteors hitting the moon will also be burning up as meteors in Earth's skies from the direction of the dim constellation Camelopardalis the Giraffe located in the northern sky below Polaris in the Little Dipper. Stellarium
Any meteors hitting the moon will also be burning up as meteors in Earth’s skies from the direction of the dim constellation Camelopardalis the Giraffe located in the northern sky below Polaris in the Little Dipper. Stellarium

“The models indicate the Camelopardalids have some big particles but move slowly around 16 ‘clicks’ a second (16 km/sec or 10 miles per second). It all depends on kinetic energy”, he added. Kinetic energy is the energy an object possesses due to its motion. Even small objects can pack a wallop if they’re moving swiftly.


Bright lunar meteorite impact recorded on video on September 11, 2013. The estimated 900-lb. space rock flared to 4th magnitude.

Lunar crescents are ideal for meteor impact monitoring because much of the moon is in shadow, illuminated only by the dim glow of earthlight. Any meteor strikes stand out as tiny flashes against the darkened moonscape. For casual watching of lunar meteor impacts, you’ll need a 4-inch or larger telescope magnifying from 40x up to around 100x. Higher magnification is unnecessary as it restricts the field of view.

I can’t say how easy it will be to catch one, but it will require patience and a sort of casual vigilance. In other words, don’t look too hard. Try to relax your eyes while taking in the view. That’s why the favored method for capturing lunar impacts is a video camera hooked up to a telescope set to automatically track the moon. That way you can examine your results later in the light of day. Seeing a meteor hit live would truly be the experience of a lifetime. Here are some additional helpful tips.

Meteorite impact flashes seen from 2005 to the present. Fewer are seen in the white areas (lunar highlands) because flashes blend in compared to those occurring on the darker lunar 'seas' or maria. Credit: NASA
Meteorite impact flashes seen from 2005 to the present. Fewer are recorded in the white areas (lunar highlands) because the flashes blend into the landscape compared to those occurring on the darker lunar ‘seas’ or maria. Click for more information on lunar impacts. Credit: NASA

On average, about 73,000 lbs. (33 metric tons) of meteoroid material strike Earth’s atmosphere every day with only tiny fraction of it falling to the ground as meteorites. But the moon has virtually no atmosphere. With nothing in the way, even small pebbles strike its surface with great energy. It’s estimated that a 10-lb. (5 kg) meteoroid can excavate a crater 30 feet (9 meters) across and hurl 165,000 lbs. of lunar soil across the surface.

A meteoroid that size on an Earth-bound trajectory would not only be slowed down by the atmosphere but the pressure and heat it experienced during the plunge would ablate it into very small, safe pieces.

NASA astronomers are just as excited as you and I are about the potential new meteor shower. If you plan to take pictures or video of meteors streaking through Earth’s skies or get lucky enough to see one striking the moon, please send your observations / photos / videos to Brooke Boen ([email protected]) at NASA’s Marshall Space Flight Center. Scientists there will use the data to better understand and characterize this newly born meteor blast.

On the night of May 23-24, Bill Cooke will host a live web chat from 11 p.m. to 3 a.m. EDT with a view of the skies over Huntsville, Alabama. Check it out.

 

 

Posted on by Jason Major

Watch the Trailer for “The Last Man on the Moon”

Gene Cernan on the Moon during the final EVA of the Apollo 17 mission, Dec. 13, 1972 (NASA/JSC scan)

On December 14, 1972, at about 5:40 a.m. GMT, Apollo 17 astronaut Eugene Andrew “Gene” Cernan returned to the lunar module Challenger after the end of the third mission EVA to join Harrison “Jack” Schmitt, completing nearly two and a half days of surface operations within the Taurus-Littrow site and officially becoming the last human to set foot upon the lunar surface. No one has returned since, and to this day the 80-year-old Cernan still holds the title of “last man on the Moon.”

If that’s not the perfect setup for a documentary film, I don’t know what is. Luckily for us there’s one in the works.

“The Last Man on the Moon,” from UK-based Mark Stewart Productions, tells the story of Gene Cernan and his accomplishments against the backdrop of the Apollo era, when superpowers competed for dominance in space and hotshot flyboys became international heroes. With firsthand accounts from Cernan himself and his family, along with several other astronauts and NASA celebrities, it’s an emotional and intimate account of America’s last lunar voyage.

Watch the trailer below:

According to IMDB the 99-minute documentary directed by Mark Craig is slated for release in the UK (and hopefully U.S.!) sometime this year, although an exact date isn’t listed. There have been advance screenings very recently, at some of which Cernan was present for Q&A sessions. Some viewers are calling it “the best space documentary they have seen” so needless to say I’m pretty excited about it!

You can keep up with the status of the film (and see some exclusive astronaut photos) by liking the Facebook page here and joining the mailing list on the official site.

And yes, we do need more films like this.

“I really wanted to reach out, stick it in my spacesuit and bring it home and show it to everybody: this is what it feels like.”
– Gene Cernan

Earth over the LM seen from the Apollo 17 landing site (NASA/JSC scan)
Earth over the LM seen from the Apollo 17 landing site (NASA/JSC scan)

Video © Mark Stewart Productions. All rights reserved.

Posted on by Nancy Atkinson

Astrophotos: Occultation of Saturn

Saturn heading behind the Moon on May 14, 2014. Credit and copyright: Silveryway on Flickr.

Observers in Australia and New Zealand had a special treat this week: watching Saturn disappear behind the Moon during an event called an occultation. (You can read all the details of how and why this happens here in our preview article.) Catching an event like this with a camera is tricky… the bright Moon can wash out the comparatively tiny (from our vantage point) planet Saturn. But here, several astrophotographers had success. Above is a nice view from Silveryway on Flickr.

See an animation of the event below from astroblogger Ian Musgrave:

An animated gif of the occulation of Saturn by the Moon on May 14, 2014. Credit and copyright: Ian Musgrave.

Ian Musgrave from Australia used a 4″ Newtonian telescope, with a “Point and Shoot” Canon IXUS attached with inifinty to infinity focussing, 3xZoom, and a 25mm eye piece. You can see his entire set of images on his website here.

Widefield view of the occultation of Saturn on May 14, 2014. Credit and copyright: Ian Musgrave.
Widefield view of the occultation of Saturn on May 14, 2014. Credit and copyright: Ian Musgrave.

Peter Lake, also from Australia not only took images of the event, but also did a live Hangout on G+.

“Live hangouts and driving a telescope live is a tricky business,” Peter wrote on his website. “I lost focus playing around trying to improve the image due to the thin cloud.” He added that the night sky wasn’t ideal that evening. “The full moon was shining through thin clouds, washing out a bit of the detail.”

Saturn getting ready to head behind the Moon. Credit and copyright: Peter Lake.
Saturn getting ready to head behind the Moon. Credit and copyright: Peter Lake.

You can watch a replay of Peter’s Hangout below:

Saturn and the Moon diffusion. The clouds drifted across the sky, Saturn and the Moon shone bright, the view from the UK. Credit and copyright: Sarah and Simon Fisher.
Saturn and the Moon diffusion. The clouds drifted across the sky, Saturn and the Moon shone bright, the view from the UK. Credit and copyright: Sarah and Simon Fisher.

Sarah and Simon Fisher from the UK captured this “diffused” view of Saturn close the Moon on the evening of May 13, 2014.

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Posted on by Nancy Atkinson

Phobos & Deimos — The Moons of Mars Explained

Where did Mars’ moons Phobos and Deimos come from? How did they end up in orbit around Mars? This cool video from the folks at Kurzgesagt answers the most-oft asked questions about these mini moons.

You should also check out their other wonderful videos, like the one about our own Moon, below, which explains how big our Moon really is. The answer might surprise you.

Continue reading “Phobos & Deimos — The Moons of Mars Explained”
Posted on by Bob King

Saturn Disappears Behind the Full Flower Moon May 14 – Watch it Live

Simulation of the moon closing in on Saturn just prior to occultation. Credit: Gianluca Masi using SkyX software

Funny thing. Skywatchers are often  just as excited to watch a celestial object disappear as we are to see it make an appearance. Early Wednesday morning (May 14) the Full Flower Moon will slip in front of  Saturn, covering it from view for about an hour for observers in Australia and New Zealand. If you don’t live where the dingoes roam, no worries. You can watch it online.And no matter where you are on the planet, the big moon will accompany the ringed planet across the sky this Tues. night-Weds. morning.


Moon-Saturn occultation from Perth, Australia Feb. 22, 2014 captured by Colin Legg

Occultations of stars happen swiftly. The moon’s limb meets the pinpoint star and bam! it’s gone in a flash. But Saturn is an extended object and the moon needs time to cover one end of the rings to the other. Planetary occultations afford the opportunity to remove yourself from planet Earth and watch a planet ‘set’ and ‘rise’ over the alien lunar landscape. Like seeing a Chesley Bonestell painting in the flesh.

Saturn and the moon tomorrow night just before midnight as viewed from the Midwestern U.S. View faces south-southeast. Stellarium
Saturn and the moon Tuesday night (May 13) just before midnight as viewed from the U.S. Stellarium

As the moon approaches Saturn, the planet first touches the lunar limb and then appears to ‘set’ as it’s covered by degrees. About an hour later, the planet ‘rises’ from the opposite limb. Planetary occultations are infrequent and always worth the effort to see.

Seen from the northern hemisphere and equatorial regions, the nearly full moon will appear several degrees to the right or west of Saturn tomorrow night (May 13). As the night deepens and the moon rolls westward, the two grow closer and closer. They’ll be only a degree apart (two full moon diameters) during Wednesday morning twilight seen from the West Coast. Northern hemisphere viewers will notice that the moon slides to the south of the planet overnight.

Map showing the region where the occultation of Saturn will be visible. Click to get the times of Saturn's disappearance and reappearance for individual cities. Times are given in UT or Universal Time. Add 9.5 hours for Australian Central Standard Time. Credit: IOTA
Map showing the region where the occultation of Saturn will be visible. Click to get times of Saturn’s disappearance and reappearance for individual cities. Times shown are UT or Universal Time. Add 9.5 hours for Australian Central Standard Time. Credit: IOTA

Skywatchers in Australia will see the moon cover Saturn during convenient early evening viewing hours May 14:

* 8:09  p.m. local time from Adelaide

* 9:05 p.m.  Brisbane

* 8:50 p.m.  Melbourne

* 8:53 p.m. Canberra

* 8:56 p.m. from Sydney (More times and a map – click HERE)

Before the occultation, Saturn will shine close to the moon’s upper right and might be tricky to see with the naked eye because of glare.

Binoculars will easily reveal the planet, but a telescope is the instrument of choice. Even a small scope magnifying at least 30x will show Saturn and its rings hovering above the bright edge of the moon. Stick around. About an hour later, Saturn will re-emerge along the moon’s lower left limb.

Saturn and its moons Tuesday night May 13 around 10 p.m. CDT. Titan's the brightest and easiest. Iapetus ranges from magnitude +10 when it's west of Saturn and we see its bright hemisphere to magnitude +12 when it's west of the planet as it will be this week. Created with Meridian software
Saturn and its moons Tuesday night May 13 around 10 p.m. CDT. Titan’s the brightest and easiest moon to see at magnitude +8.5. Iapetus ranges from magnitude +10 when it’s west of Saturn and we see its bright hemisphere to magnitude +12 when it’s east of the planet. Created with Meridian software

Meanwhile, back in the western hemisphere, we’ll watch the nearly full Flower Moon make a close pass of the planet. If you’ve had difficulty finding the celestial ring bearer, you’ll have no problem Tuesday night. Take a look at Saturn’s wonderful system of rings in your telescope – they’re tipped nearly wide open this year. For even more fun, see how many moons you can spot. And don’t forget, you can watch it online courtesy of astrophysicist Gianluca Masi. His Virtual Telescope website will broadcast the occultation live starting at 10:15 Universal Time May 14 (6:15 a.m. EDT, 5:15 CDT, 4:15 MDT and 3:15 PDT).

Posted on by Bob King

Observing Alert: See Mercury’s Best Evening Show of the Year

Mercury starts its best period of visibility in the evening sky for skywatchers at mid-northern latitudes this weekend. This map shows the sky facing northwest about 40 minutes after sundown. Bright Jupiter also provides a convenient sightline for locating Mercury. Stellarium

Don’t let furtive Mercury slip through your fingers this spring. The next two and a half weeks will be the best time this year  for observers north of the tropics to spot the sun-hugging planet. If you’ve never seen Mercury,  you might be surprised how bright it can be. This is especially true early in its apparition when the planet looks like a miniature ‘full moon’. 

Mercury, like Venus, displays phases as it revolves around the sun as seen from Earth's perspective outside Mercury's orbit. Credit: Bob King
Mercury, like Venus, displays phases as it revolves around the sun as seen from Earth’s perspective outside Mercury’s orbit. Both Mercury and Venus appear largest when nearly lined up between Earth and sun at inferior conjunction. Planets not to scale and phases shown are approximate. Credit: Bob King

Both Venus and Mercury pass through phases identical to those of the moon. When between us and the sun, Mercury’s a thin crescent, when off to one side, a ‘half-moon’ and when on the far side of the sun, a full moon. This apparition of the planet is excellent because Mercury’s path it steeply tilted to the horizon in mid-spring.

We start the weekend with Mercury nearly full and brighter than the star Arcturus. Twilight tempers its radiance, but :

* Find a location with a wide open view to the northwest as far down to the horizon as possible.

* Click HERE to get your sunset time and begin looking for the planet about 30-40 minutes after sunset in the direction of the sunset afterglow.

* Reach your arm out to the northwestern horizon and look a little more than one vertically-held fist  (10-12 degrees) above it for a singular, star-like object. Found it? Congratulations – that’s Mercury!

* No luck? Start with binoculars instead and sweep the bright sunset glow until you find Mercury. Once you know exactly where to look, lower the binoculars from your eyes and you should see the planet without optical aid. And before I forget – be sure to focus the binoculars on a distant object like a cloud or the moon before beginning your sweeps. I guarantee you won’t find Mercury if it’s out of focus.

Through a telescope, Mercury looks like a gibbous moon right now but its phase will lessen as it moves farther to the ‘left’ or east of the sun. Greatest eastern elongation happens on May 24. On and around that date the planet will be farthest from the sun, standing 12-14 degrees high 40 minutes after sundown from most mid-northern locales.

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Mercury is even better placed on May 19 but fades and begins to drop back down toward the horizon late in the month. Stellarium

The planet fades in late May and become difficult to see by early June. Inferior conjunction, when Mercury passes between the Earth and sun, occurs on June 19. Unlike Venus, which remains brilliant right up through its crescent phase, Mercury loses so much reflective surface area as a crescent that it fades to magnitude +3. Its greater distance from Earth, lack of reflective clouds and smaller size can’t compete with closer, brighter and bigger Venus.

Mercury's path across the solar disk as seen from the Solar and Heliospheric Observatory (SOHO) on November 8, 2006. The transit was visible in eastern Europe and the eastern hemisphere. Credit: NASA.
When a planet crosses the disk of the sun it’s called a transit. Mercury’s path across the solar disk is seen from the Solar and Heliospheric Observatory (SOHO) on November 8, 2006. Credit: NASA.

Mercury’s 7-degree inclined orbit means it typically glides well above or below the sun’s disk at inferior conjunction. But anywhere from 3 up to 13 years in either November or May the planet passes directly between the Earth and sun at inferior conjunction and we witness a transit. This last happened for U.S. observers on Nov. 8, 2006; the next transit occurs exactly two years from today on May 9, 2016. That event will be widely visible across the Americas, Western Europe and Africa. After having so much fun watching the June 2012 transit of Venus I can’t wait.

 

Posted on by Nancy Atkinson

The Newest ‘Earthrise’ Image, Courtesy of the Lunar Reconnaissance Orbiter

The Moon, tiny Earth and the vastness of space,as seen by the Lunar Reconnaissance Orbiter Wide Angle Camera (WAC). Credit: NASA/GSFC/Arizona State University.

That’s Earth. That’s us. Way off in the distance as a fairly small, blue and swirly white sphere. This is the newest so-called “Earthrise” image, and it was taken on February 1, 2014 by the Lunar Reconnaissance Orbiter.

“LRO experiences twelve earthrises every day, however LROC is almost always busy imaging the lunar surface so only rarely does an opportunity arise such that LROC can capture a view of the Earth,” wrote LROC Principal Investigator Mark Robinson on the instrument’s website. “On the first of February of this year LRO pitched forward while approaching the north pole allowing the LROC WAC to capture the Earth rising above Rozhdestvenskiy crater (180-km diameter).”

Robinson went on to explain that the Earth is a color composite from several frames and the colors are very close to what the average person would see if they were looking back at Earth themselves from lunar orbit. “Also, in this image the relative brightness between the Earth and the Moon is correct, note how much brighter the Earth is relative to the Moon,” Robinson said.

Gorgeous.

Below is a gif image that demonstrates how images are combined over several orbits to create a full image from the Wide Angle Camera.

A gif image showing the “venetian blind” banding demonstrates how a WAC image is built up frame-by-frame. The gaps between the frames are due to the real separation of the WAC filters on the CCD. Credit: NASA/GSFC/Arizona State University.

The frames were acquired at two second intervals, so the total time to collect the sequence was 5 minutes. The video is faster than reality by a factor of about 20.

Posted on by Fraser Cain

Virtual Star Party – May 4, 2014: It’s Galaxy Season!

Hosts: Fraser Cain and Scott Lewis
Astronomers: Gary Gonella, Andrew Dumbleton, Stuart Foreman, David Dickinson, Shahrin Ahmad and special guest Henna Khan from Bombay, India

Tonight’s Views:
the Moon’s surface
M44 Beehive Cluster
Neutron Star B224 from HST
All-Sky View
Mars with ice caps and Hellas Basin visible
Comet C/2012 K1 PanSTARRS
Stuart demonstrating how to work with software to process images
M51a Whirlpool Galaxy
M53 Globular Cluster
Rosette Nebula – NGC 2237, 2238, 2239 and 2246
Saturn
Horsehead Nebula (Barnard 33 in emission nebula IC 434) and Flame Nebula (NGC 2024) with a satellite trail
NGC 5139 Omega Centauri
M42 Orion Nebula
M63 Sunflower Galaxy
NGC 7635 Bubble Nebula
Large and Small Magellanic Clouds

We hold the Virtual Star Party every Sunday night as a live Google+ Hangout on Air. We begin the show when it gets dark on the West Coast. If you want to get a notification, make sure you circle the Virtual Star Party on Google+. You can watch on our YouTube channel or here on Universe Today.