When Will Mars Be Close to Earth?

As neighboring planets, Earth and Mars have a few things in common. Both are terrestrial in nature (i.e. rocky), both have tilted axes, and both orbit the Sun within its circumstellar habitable zone. And during the course of their orbital periods (i.e. a year), both planets experience variations in temperature and changes in their seasonal weather patterns.

However, owing to their different orbital periods, a year on Mars is significantly longer than a year on Earth – almost twice as long, in fact. And because their orbits are different, the distance between our two planets varies considerably. Basically, every two years Earth and Mars will go from being “at conjunction” (where they are farther from each other) to being “at opposition” (where they are closer to each other).

Orbital Period:

Earth orbits the Sun at an average distance (semi-major axis) of 149,598,023 km (92,955,902 mi; or 1 AU), ranging from 147,095,000 km (91,401,000 mi) at perihelion to 152,100,000 km (94,500,000 mi) at aphelion. At this distance, and with an orbital velocity of 29.78 km/s (18.5 mi/s) the time it take for the planet to complete a single orbit of the Sun (i.e. orbital period) is equal to about 365.25 days.

A top-down image of the orbits of Earth and Mars. Credit: NASA

Mars, meanwhile, orbits the Sun at an average distance of 227,939,200 km (141,634,850 mi; or 1.523679 AU), ranging from 206,700,000 km (128,437,425 mi) at perihelion to 249,200,000 km (154,845,700 mi) at aphelion. Given this difference in distance, Mars orbits the Sun at a slower speed (24.077 km/s; 14.96 mi/s) and takes about 687 Earth days (or 668.59 Mars sols) to complete a single orbit.

In other words, a Martian year is almost 700 days long, which works out to being 1.88 times as long as a year on Earth. This means that every time Mars completes a single orbit around the Sun, the Earth has gone around almost twice. During the moments when they are on opposite sides of the Sun, this is known as a “conjunction”. When they are on the same side of the Sun, they are at “opposition”.

Mars Opposition:

By definition, a “Mars opposition” occurs when planet Earth passes in between the Sun and planet Mars. The term refers to the fact that Mars and the Sun appear on opposite sides of the sky. Because of their orbits, Mars oppositions happens about every 2 years and 2 months – 779.94 Earth days to be precise. From our perspective here on Earth, Mars appears to be rising in the east just as the Sun sets in the west.

About every two years, the Earth passes Mars as they orbit around the Sun. Credit: NASA

After staying up in the sky for the entire night, Mars then sets in the west just as the Sun begins to rise in the east.  During an opposition, Mars becomes one of the brightest objects in the night sky, and is easy to see with the naked eye. Through small telescopes, it will appear as a large and bright object. Through larger telescopes, Mars’ surface features will even become apparent, which would include its polar ice caps.

An opposition can also occur anywhere along Mars’ orbit. However, opposition does not necessary mean that the two planets are at their closest overall. In truth, it just means that they are are at their closest point to each other within their current orbital period. If Earth and Mars’ orbits were perfectly circular, they would be closest to each other whenever they were at opposition.

Instead, their orbits are elliptical, and Mars’ orbit is more elliptical than Earth’s – which means the difference between their respective perihelion and aphelion is greater. Gravitational tugging from other planets constantly changes the shape of our orbits too – with Jupiter pulling on Mars and Venus and Mercury affecting Earth.

Color composite of Mars from seven of its previous oppositions, taken with the Hubble Space Telescope. Credit: NASA/ESA/HST

Lastly, Earth and Mars do not orbit the Sun on the exact same plane – i.e. their orbits are slightly tilted relative to each other. Because of this, Mars and Earth become closest to each other only over the long-term. For instance, every 15 or 17 years, an opposition will occur within a few weeks of Mars’ perihelion. When it happens while the Mars is closest to the sun (called “perihelic opposition”), Mars and Earth get particularly close.

And yet, the closest approaches between the two planets only take place over the course of centuries, and some are always closer than others. To make matters even more confusing, over the past few centuries, Mars’ orbit has been getting more and more elongated, carrying the planet even nearer to the Sun at perihelion and even farther away at aphelion. So future perihelic oppositions will bring Earth and Mars even closer.

On August 28th, 2003, astronomers estimated that Earth and Mars were just 55,758,118 km (34,646,488 mi; 0.37272 AU) apart. This was the closest the two planets had come to each other in almost 60,000 years. This record will stand until August 28th, 2287, at which point the planets will be an estimated 55,688,405 km (34,603,170.6 mi; 0.372254 AU) from each other.

Future Oppositions:

Want to organize your schedule for the next time Mars will be close to Earth? Here are some upcoming dates, covering the next few decades. Plan accordingly!

  • July 27th, 2018
  • October 13th, 2020
  • December 8th, 2022
  • January 16th, 2025
  • February 19th, 2027
  • Mar 25th, 2029
  • May 4th, 2031
  • June 27th, 2033
  • September 15th, 2035
  • November 19th, 2037
  • January 2nd, 2040
  • February 6th, 2042
  • March 11th, 2044
  • April 17th, 2046
  • June 3rd, 2048
  • August 14th, 2050

And in case your interested, Mars will be making close approaches on two occasions this century. The first will take place on August 14th, 2050, when Mars and Earth will be 55.957 million km (34.77 million mi; or 0.374051 AU) apart; and on September 1st, 2082, when they will be 55,883,780 km (34,724,571 mi; 0.373564 AU) apart.

There’s a reason missions to Mars depart from Earth every two years. Seeking to take advantage of shorter travel times, rovers, orbiters and landers are launched to coincide with Mars being at opposition. And when it comes time to send crewed mission to Mars (or even settlers) the same timing will apply!

We have written many interesting articles about Mars here at Universe Today. Here’s How Far is Mars from Earth?, How Long Does it Take to Get to Mars?, How Long is a Year on Mars?, How Far is Mars from the Sun?, and How Long Does it Take Mars to Orbit the Sun?

For more information, here’s a comprehensive schedule of upcoming Mars oppositions.

Astronomy Cast also has some wonderful episodes on the Red Planet. Here’s Episode 52: Mars, and Episode 91: The Search for Water on Mars.

Sources:

How Long Does it Take Mars to Orbit the Sun?

Given it’s similarities to Earth, Mars is often referred to as “Earth’s Twin”. Like Earth, Mars is a terrestrial planet, which means it is composed largely of silicate rock and minerals that are differentiated into a core, mantle and crust. It is also located within the Sun’s “Goldilocks Zone” (aka. habitable zone), has polar ice caps, and once had flowing water on its surface. But beyond these, Mars and Earth are very different worlds.

In addition to their stark contrasts in temperature, surface conditions, and exposure to harmful radiation, Mars also takes a significantly longer time to complete a single orbit of the Sun. In fact, a year on Mars is almost twice as long as a year here on Earth – lasting 686.971 days, which works out to about 1.88 Earth years. And in the course of that orbit, the planet undergoes some rather interesting changes.

Continue reading “How Long Does it Take Mars to Orbit the Sun?”

Into the Red: Our Complete Guide to Mars Opposition 2016

Mars 2014

Ready to explore the Red Planet? Starting in May, Mars invades the evening skies of the Earth, as it heads towards opposition on May 22nd. Not only does this place Mars front and center for prime time viewing, but we’re headed towards a cycle of favorable oppositions, with Mars near perihelion, while Earth is near aphelion. Continue reading “Into the Red: Our Complete Guide to Mars Opposition 2016”

Revealed: Mars to Appear Larger Than a Full Moon!

We can finally reveal the truth.

A massive conspiracy, spanning over a decade, has been revealed at last by basement bloggers, YouTubers and Facebook users everywhere, implicating ‘big-NASA’ and the powers that be in a massive cover-up.

Yes, it’s the month of August once again, and the Red Planet Mars is set to appear ‘larger than a Full Moon’ over the skies of Earth, as it apparently does now… every year.

Um, no. Stop. Just… stop.

Sure, by now, you’ve had the hoax forwarded to you by that certain well-meaning, but astronomically uninformed family member/co-worker/anonymous person on Facebook.

What’s new under the Sun concerning the August Mars Hoax? To see where the hoax was born, we have to journey all the way back to the close opposition of Mars on August 27th, 2003. Hey, we actually took two weeks leave in the Fall of 2003 just to sketch and image Mars each night from our backyard lair in the Sonoran desert south of Tucson, Arizona from the then known Very Small Optical Observatory. Those were the days. We measured dial-up internet speeds in kbit/s, ‘burned CDs,’ and Facebook and Twitter were still some years away. Even spam e-mail was still sorta hip.

Two years later in 2005, we were all amused, as the ‘August Mars Hoax’ chain email made its first post-2003 appearance in our collective inboxes. Heck, we were even eager in those halcyon days to take to the nascent web, and do that new hipster thing known as ‘blogging’ to explain just exactly why this couldn’t be so to the masses.

Later in 2006, 2007, and 2008, it wasn’t so funny.

The Mars Hoax just wouldn’t die. “One more unto the breach,” the collective astro-blogging community sighed, as we all dusted off last year’s post explaining how the Red Planet could never approach our own fair world so closely.

It. Just. Couldn’t. Because orbital mechanics. Because physics.

Even the advent of social media couldn’t kill in annual onslaught of the Mars Hoax, and over a Spiderman movie reboot later, we’re now seeing it shared across Facebook, Twitter and more.

Sure, the Mars Hoax is as fake as Donald Trump’s hair. If there’s any true science lesson to learn here, it’s perhaps the mildly interesting social science study of just how the Mars hoax weathers the lean months of winter, to reemerge every August.

Here’s the skinny (again!) on just why Mars can’t appear as large as the Full Moon:

-The Moon is 3,474 kilometers in diameter, and orbits the Earth at an average distance of just under 400,000 kilometers.

-At this distance, the Moon can only appear about 30’ (half a degree) across.

-Think that’s a lot? Well, you could ring the 360 degree circle of the local horizon with 720 Full Moons.

-Mars, like the Earth, orbits the Sun. Even with Earth at aphelion (its most distant point) and Mars at perihelion, we’re still 206.7 – 151.9 = 54.8 million km apart. Sure, aphelion and perihelion of our respective worlds don’t quite line up in our current epochs, but we’ll indulge imagination and fudge things a bit.

-Though Mars is just over 2x times larger in diameter than the Moon, it’s also more than 143 times farther away, even at its said hypothetical closest.

Credit Dave Dickinson
Mars vs Earth; oppositions from 2003 to 2018, including perihelion and aphelion positions. Image credit: Dave Dickinson

-Still want to see Mars as big as a Full Moon? Perhaps one day, astronauts will, though they’ll have to be orbiting just over a 800,000 km from the Red Planet to do it.

If we sound a little pessimistic in our characterizing the Mars Hoax as a recurring non-story, it’s because we see many truly fantastic things in space news that get far from their far shake. Real stories, of collapsing stars, rogue exoplanets, and intrepid rovers exploring distant worlds. Tales of humanoids, exploring space and doing the very best and noble things humanoids as a species can do.

Want to trace the history the Mars Hoax?

Here’s the saga of Universe Today’s coverage of all things ‘Mars Hoax’ since those olden days of the early web:

2005- No, Mars Won’t Look as Big as the Moon

2006- No, Mars Won’t Look as Big as the Moon in August

2007- Will Mars Look as Big as the Moon on August 27? Nope

2008- Please (Again) – Mars Will NOT Look as Big as the Full Moon

2009- Mars Will NOT Look as Big as the Full Moon… But You Can Watch it Get Closer

2010- Tonight’s the Night Mars Will NOT Look as Big as the Full Moon

2011- Is the Moon Mars Myth Over?

2013- The Cyber Myth that Just Won’t Die

2016- ????

Hey, it looks like the hoax did take a break in 2012 and 2014, so that’s encouraging at least…

The great Mars opposition of 2003. image credit: Dave Dickinson
The great Mars opposition of 2003. Image credit: Dave Dickinson

Now, I’m going to do my best to truly terrify all of science blogger-dom, and leave you with one final thought to consider. Mars reaches opposition (otherwise known in astronomical circles as ‘when it’s really nearest to the Earth’) once roughly every 26 months. All oppositions of Mars are not created equal, owing mostly to the eccentric orbit of the Red Planet. We have another fine opposition of Mars coming right up next year on May 22nd, 2016, followed by one that’s very nearly as favorable as the historic 2003 opposition in 2018, falling juuuuust shy of August on July 28th of that year…

Will the Mars Hoax meme find a new unwitting audience, and with it, new life?

Sleep tight…. we’ll be covering real science stories in the meantime, ’til we’re called to do battle with the Mars Hoax once again.

Mars Opposition Season 2014: Images From Around the World

Did you see it? Last night, the Red Planet rose in the east as it passed opposition for 2014, and astrophotographers the world over were ready to greet it.  And although Mars gets slightly closer to us over the coming week, opposition marks the point at which Mars is 180 degrees “opposite” to the setting Sun in Right Ascension as viewed from our Earthly vantage point and denotes the center of the Mars observing season. Opposition only comes around once about every 26 months, so it’s definitely worth your while to check out Mars through a telescope now if you can. We’ve written about prospects for observing Mars this season, and the folks at Slooh and the Virtual Telescope Project also featured live views of the Red Planet last night. We also thought we’d include a reader roundup of pics from worldwide:

Mars and Spica rising over the telescope domes at Kitt Peak, Arizona. The 2.1 metre dome is on the left, and the 0.9 metre dome is to the right. Credit-Rob Sparks @halfastro
Mars and Spica rising over the telescope domes at Kitt Peak, Arizona. The 2.1 metre dome is on the left, and the 0.9 metre dome is to the right. Credit-Rob Sparks @halfastro.

Even near opposition, Mars presents a challenge to observers. In 2014, Mars only reaches 15 arc seconds maximum in apparent size, a far cry from its 25″ appearance during the historic 2003 opposition.  Now for the good news: we’re in a cycle of improving oppositions…  the next one on May 22nd, 2016 will be better still, and the 2018 opposition will be nearly as favorable as the 2003 appearance!

Mars as seen from the Netherlands at 0:26 UT... about 3 hours past opposition. Credit- Christian Fröschlin.
Mars as seen from the Netherlands at 0:26 UT… about 3 hours past opposition. Credit- Christian Fröschlin @chrfde.

And you can see just how technology in the amateur astronomy community has improved with each successive appearance of Mars over the years. Early observers were restricted to sketching features glimpsed during fleeting moments of steady seeing. Even during the film era of photography, absurdly long focal lengths were required to yield even a tiny speck of a dot. And even then, the “graininess” of the film tended to smear and yield a blurry image with few details to be seen.

The  advent of digital photography opened new vistas on planetary imaging. Now backyard astrophotographers are routinely taking images using stacking techniques and processing to “grab” and align those moments of good seeing. These images are often now better that what you’d see in a text book taken from professional observatories only a few decades ago!

And you can now easily modify a webcam to take decent planetary images that can then be stacked and processed with software freely available on the web.

…And check out this video animation also by Christian Fröschlin that shows the rotation (!) of Mars:

Mars as seen from Ottawa, Canada, taken using an IPhone 4S through a NexStar 8SE telescope on April 4th, 2014. Awesome! Credit-Andrew Symes @FailedProtostar
Mars as seen from Ottawa, Canada, taken using an IPhone 4S through a NexStar 8SE telescope on April 4th, 2014. Awesome! Credit-Andrew Symes @FailedProtostar

Shahrin Ahmad made an excellent video from Malaysia that demonstrates just what raw captured images of Mars look like before processing:

Note that the large dark triangular region is Syrtis Major.

Mars annotated, a stack of 1128 frames shot at 666x. Credit-Mike Weasner/Cassiopeia Observatory.
Mars annotated, a stack of 1128 frames shot at 666x. Credit-Mike Weasner/Cassiopeia Observatory.

The northern polar cap is currently tipped towards us, as it’s northern hemisphere summertime on Mars. Many images reflect this prominent feature, as well as the orographic clouds skirting the Hellas basin that have been the hallmark of the Mars opposition of 2014. These are also apparent visually at the eyepiece. It’s worth staying up a bit towards local midnight to observe and image Mars, as it transits at its maximum  elevation — and is above the murk of the sky low to the horizon — right around this time.

Mars captured through a Celestron C6 SCT telescope on April 5th, 2014. Credit: Joel Tonyan.
Mars captured through a Celestron C6 SCT telescope on April 5th, 2014. Credit: Joel Tonyan.
Mars: a study of color contrasts on the eve of opposition. Credit-Laura Austin @LAismylady
Mars: a study of color contrasts on the eve of opposition. Credit-Laura Austin @LAismylady

And Mars observing season doesn’t end this week. Mars makes its closest passage to the Earth for 2014 next Monday on April 14th at 0.618 Astronomical Units (A.U.s) distant. Mars will occupy the evening sky for the remainder of 2014 before finally reaching solar conjunction on June 14th, 2015. Mars will still be greater than a respectable 10″ in apparent size until June 24th and will continue to offer observers a fine view at the eyepiece.

Mars as seen from Rhode Island on the night of opposition. Credit-Cherie @KelieAna
Mars as seen from Rhode Island on the night of opposition. Credit-Cherie @KelieAna

And don’t forget, that waxing gibbous Moon is now homing in on Mars and will only sit a few degrees away from the Red Planet and Spica on the night of the April 14th/15th, 2014 during a fine total lunar eclipse. And no, a “red” planet + a “blood red” eclipsed Moon does not equal doomsday… but it’ll make a great photo op!

Mars imaged using a 150 mm scope. Credit-Sergei Golyshev under a Creative Commons Share-Alike 2.0 Generic License.
Mars imaged using a 150 mm scope. Credit-Sergei Golyshev under a Creative Commons Share-Alike 2.0 Generic License.

… and finally, Mars and the bright blue-white star Spica offered us a fine morning view as the storm front passed over Astroguyz HQ here in Florida this AM:

Author
Mars, Spica, and our partly cloudy terrestrial atmosphere. Photo by author.

Want something more? Have you ever seen Mars… in the daytime? Currently shining at magnitude -1.5, its just possible if you known exactly where to look for it low to the east about 10 minutes or so before local sunset. In fact, near opposition is the only time you can carry this unusual feat of visual athletics out. The best chance in 2014 is on the evening of April 13th and 14th, when the waxing gibbous Moon lies nearby:

Starry Night education software
Looking east on the evening of April 13th, just before sunset. Credit: Starry Night education software.

Good luck, and thanks to everyone who imaged Mars this season!

 

 

 

 

 

 

 

 

 

 

 

Night of the Red Planet: Mars Opposition 2014 Coming Soon!

Mars attacks and comes to a night sky near you this month, and the folks at the Virtual Telescope Project and Slooh are bringing it to you live and in color. Unlike most planets, “Mars viewing season” comes around only once about every two years. And while Mars is shining bright in the sky right now, the “official” event of Mars being closest to Earth happens next week on April 8th, when the Red Planet reaches opposition and shines at magnitude -1.5 in the constellation Virgo.

We’ve written about the prospects and circumstances for viewing Mars this opposition season; now it’s time to watch it live. The webcast starts at 23:00 Universal Time (UT) or / 7:00 PM EDT on the night of Tuesday April 8th, and will feature real-time images brought to you via robotic telescopes worldwide. Hosted by astrophysicist Gianluca Masi and run in conjunction with Astronomers Without Borders, this online observing session of Mars also occurs during Global Astronomy Month. Anyone who tuned in for their recent online Messier Marathon and live broadcasts of several recent Near-Earth Asteroids past our fair planet knows that they’re in for quite a treat!

Want more? Or simply want dual screen live views of “all Mars, all the time?” Our dependable friends over at Slooh will be chronicling the Mars opposition on the same night, starting at a slightly different bat-time at 02:00 UT (the morning of the 9th) which is 10:00 PM EDT the evening of the 8th. Slooh will be presenting a live feed from its automated telescopes based in the Canary Islands off of the coast of West Africa and will feature live commentary from hosts Paul Cox and astronomer and author of The Sun’s Heartbeat Bob Berman.

“Mars has held disproportionate focus for humans since ancient times,” Berman said in a recent press release. “It is neither the closest planet, nor the largest, nor the most detailed through telescopes. Nonetheless, it is the only planet in the universe that shows distinct and sometimes detailed surface features through our telescopes. It is also the most Earthlike body in the known universe, with oxygen bound into its soil and water contained in its ices. Therefore, during the brief two weeks when it comes near us every 26 months, it deserves the limelight.”

Indeed, Mars has captivated observers ever since Christiaan Huygens sketched the first blurry surface feature Syrtis Major back in 1659. Percival Lowell enthralled the public imagination with his sketches of what he thought were canals built by an intelligent and ancient civilization on the Red Planet, and astronomer David Peck Todd once proposed to signal said Martians via balloon aloft in 1909. The SETI Institute’s Seth Shostak noted in his book Confessions of an Alien Hunter that to the average person on the street in the early 20th century, the idea that Mars was inhabited was a given.

Of course, the reality revealed to us by the early Mariner missions in the 1960s onwards paints a bleak picture of a cratered world with a tenuous atmosphere inhospitable to life as we know it.

Still, Mars is a real world, somewhere that rovers are rolling across and exploring even as we peer at it though the eyepiece this month. Six months prior to opposition also the best opportunity to send spacecraft to Mars, and later this year, NASA’s MAVEN and India’s Mars orbiter Mangalyaan both launched in late 2013 will complete the trip.

Mars approaches Earth during the month of April. Credit: Efrain Morales Rivera/Jaicoa Observatory/Aguadilla, Puerto Rico.
Mars approaches Earth during the month of April. Credit: Efrain Morales Rivera/Jaicoa Observatory/Aguadilla, Puerto Rico.

Observing the Red Planet through the eyepiece is easy. The most conspicuous feature is the white northern pole cap, currently tipped towards us. Orographic clouds have also been imaged by amateurs recently over the Hellas basin, and a planet wide dust storm could always crop up at any time. A Martian day is only 37 minutes longer than the Earth’s, meaning you’re only seeing Mars rotated by about 15 degrees of longitude if you observe it at the same time each night.  At about 15” across, you could stack 120 Mars diameters as seen this week from Earth across a Full Moon. And no, Mars NEVER appears as big as a Full Moon as seen from the Earth, not this week, every August, or EVER, despite those pesky chain-emails from well meaning co-workers/friends/relatives who just know that you’re into that “space thing…”

All oppositions of Mars are not created equal. In fact, we’re coming off of a series of lackluster oppositions that’ll see Mars getting successively better until 2018, when it’ll nearly top the historic opposition of 2003. For ephemerides buffs, Mars reaches opposition — that is, it’s 180 degrees opposite to the Sun as reckoned in right ascension — on April 8th at 21:00 UT/5:00 PM EDT. It is not quite, however, at its closest to us for 2014: it has still got 0.003 AU (465,000 kilometres, a little over the distance from the Earth to the Moon) and just over 5 days before its closest approach to Earth on the night of April 14th/15th, when a total eclipse of the Moon lies just nine degrees away. The reason opposition and the closest approach of Mars to Earth are not quite in sync is because the orbits of both planets are elliptical, and while Mars is currently moving towards perihelion, Earth is heading toward aphelion on July 4th.

A photo-montage leading up to the 2003 opposition. Photos by author using a webcam turned planetcam.
A photo-montage leading up to the 2003 opposition. Photos by author using a webcam turned planetcam.

Can’t wait until the 8th?  Universe Today hosts a Virtual Star Party every Sunday evening at 11:00 PM EDT / 03:00 UT on Google+ featuring telescopes and commentary by observers and astronomers worldwide. Weather willing, Mars should be a centerpiece object for the show this Sunday night on April 6th.

Be sure to check out Mars at its best this week for 2014, either in a sky near you or online… hey, maybe we’ll be live casting the transit of Earth, the Moon and Phobos someday from Mars on the slopes of Elysium Mons on November 10th, 2084:

Let’s see, hopefully they’ll have perfected that whole Futurama “head in a jar” thing by then…

Enjoy!

 

Enter the Red Planet: A Guide to the Upcoming Mars 2014 Opposition Season

Get those telescopes ready: the coming months offer Earthbound viewers some great views of the planet Mars.

Mars reaches opposition for 2014 on April 8th. This is approaching season represents the best time to observe Mars, as the Red Planet is closest to us in April and rises in the east as the Sun sets opposite to it in the west.  Mars reaches 10” in apparent size this week. Mars is already beginning to show surface detail through a moderate-sized telescope as it continues to grow. In mid-February, Mars currently rises at around midnight local, and rides high to the south at local sunrise.

Mars imaged by Leo Aerts on February 3rd. Shot using a Celestron 14" scope, DMK 21AU618 webcam with a 2.5 powermate projection and a RGB Baader filter set.
Mars imaged by Leo Aerts on February 3rd. Shot using a Celestron 14″ scope, DMK 21AU618 webcam with a 2.5 powermate projection and a RGB Baader filter set.

The 2014 opposition of Mars offers a mixed bag for observers. Hanging around 5-10 degrees south of the celestial equator just east of the September equinoctial point in Virgo, viewing opportunities are roughly equal for both northern and southern hemisphere observers. At opposition, Mars will shine at magnitude -1.5 and present a 15.2” disk, only slightly larger than the near minimum apparition of 2012, when it appeared 13.9” across. This is a far cry from the historic 2003 appearance, when Mars nearly maxed out at 25.1” across.

Why such a difference? Because the planet Mars has an exceptionally eccentric orbit. In fact, the eccentricity for Mars is 9.3% compared to 1.7% for the relatively sedate Earth.

A decade of Mars oppositions.
A decade plus of Mars oppositions, from 2012 through 2025. Graphic created by the author.

This guarantees that all oppositions of Mars – which occur roughly 26 months/780 days apart – are not created equal. In our current epoch, Mars can pass anywhere from 0.683 to 0.373 Astronomical Units (A.U.s) from the Earth. This year’s passage sees Mars overtake us at 0.62 A.U.s or over 96 million kilometres from Earth on the night of opposition. Mars is slightly closer to us at 0.618 A.U.s six nights later on April 14th.

Why the slight difference? Well, the speedier Earth is on the inside track headed towards aphelion in July, while Mars is lagging but headed slightly inward towards perihelion just afterwards in September. This combined motion makes for a slightly closer approach just after opposition until the Earth begins to pull away.

And this also means that Mars will make its apparent retrograde loop through Virgo on the months surrounding opposition:

Mars retrograde credit-Starry Night
The motion of Mars through Virgo from March 1st through July 31st. Created by the author using Starry Night Education software.

Now for the good news. Oppositions of Mars also follow a rough 15-year cycle, meaning that they get successively closer or more distant with every two year passage. For example, the 1999 opposition of Mars had a very similar geometry to this year’s, as will to the future opposition in 2029.

And we’re currently on an improving trend: the next opposition in 2016 is much better than this year’s at 18.6” in size, and during the 2018 opposition, Mars will present a disc 24.3” across and will be nearly as favorable as the one in 2003!

It’s also worth noting that Mars sits within four degrees of the rising Moon on the evening of April 14th. The bright star Spica also sits even closer to the Full Moon on the same evening, at less than two degrees away. This particular evening is also noteworthy as it hosts the first of two lunar eclipses for 2014, both of which favor North America.

Mars April 14th.
Mars, the Full Moon and Spica rising in the east on April 14th. Created using Stellarium.

Can you catch Mars near the Moon before sundown on the 14th using binoculars? The Moon will also occult Mars on July 6th for viewers across central and South America.

Though Mars is nicknamed the Red Planet, we’ve seen it appear anywhere from a pumpkin orange to a sickly yellow hue. In fact, such a jaundiced color change can be a sign that a planet-wide dust storm is under way. Such a variation can be readily seen with the naked eye. What color does Mars appear like to you tonight?

On Mars, northern hemisphere summer starts on February 15th, 2014. This means that the northern pole cap of the planet is tipped towards us at opposition during 2014. The day on Mars is only slightly longer than Earth’s at 24 hours and 37 minutes, meaning that Mars will have seemed to rotated only an extra ~8 degrees if you observe it at the same time on each successive evening.

The white pole caps of the planet are the first feature that becomes apparent to the observer at the eyepiece. In February, Mars shows a noticeable gibbous phase in February as we get a peek at the edge of the nighttime side of the planet. Mars will be nearly “full” at opposition, after which it’ll once again take on a slightly distorted football shape.

A growing Mars.
A growing (& shrinking) Mars through the 2014 opposition season. Created by the author using Starry Night Education software.

Tracking the features of the Red Planet is also possible at moderate magnification. One of the largest features apparent is the dark area known as Syrtis Major. Sky & Telescope has an excellent and easy to use application named Mars Previewer that will show you which longitude is currently facing Earth.

Sketching the regions of Mars is a fun exercise. You’ll find that drawing planetary features at the eyepiece can sharpen your observing skills and give you a more critical eye to discern subtle detail. And this season also provides an excellent reason to turn that newly constructed planetary webcam towards Mars.

Up for a challenge? Opposition is also a great time to try and observe the moons of Mars.

moons Starry Night
The moons of Mars as seen on April 8th at around 9:00 Universal Time. Created by the author using Starry Night Education software.

Phobos and Deimos are a tough catch, but are indeed within range of amateur instruments. The chief problem lies in their close proximity to dazzling Mars: +11.5 magnitude, Phobos never strays 14” from the Red Planet in 2014, and 12.4 magnitude Deimos never travels farther than 45” away. Phobos orbits Mars once 7.7 hours — faster than the planet rotates beneath it — and Deimos orbits once every 30.3 hours. The best strategy for a successful Martian moon hunt is to either place Mars just out of the field of view at high power when a moon reaches greatest elongation or block it from view using an eyepiece equipped with an occulting bar.

Extra credit for anyone who nabs pics of the pair!

And opposition is also “Visit Mars season,” as MAVEN and India’s Mars Orbiter Mission arrive later this year. In 2016, NASA’s Mars InSight mission is slated to make the trip, and the window is fast-closing for Dennis Tito’s proposed crewed fly-by mission of Mars in 2018.

And finally, to aid you in your quest for those elusive Martian moons, reader and human astronomical calculator extraordinaire Ed Kotapish was kind enough to compile a list of favorable apparitions of the moons of Mars on the weeks surrounding opposition. (see below)

Good luck, and be sure to send in those pics of Mars and more to Universe Today!

ELONGATIONS OF THE MARTIAN MOONS
DATES AND TIMES IN UT
STARTING  3/30/2014
MAR 30
PHOBOS 0300 W
PHOBOS 0645 E
DEIMOS 0900 W
PHOBOS 1040 W
PHOBOS 1425 E
PHOBOS 1815 W
PHOBOS 2205 EMAR 31
DEIMOS 0005 E
PHOBOS 0155 W
PHOBOS 0545 E
PHOBOS 0935 W
PHOBOS 1320 E
DEIMOS 1515 W
PHOBOS 1715 W
PHOBOS 2100 E

APR 01
PHOBOS 0055 W
PHOBOS 0440 E
DEIMOS 0620 E
PHOBOS 0830 W
PHOBOS 1220 E
PHOBOS 1610 W
PHOBOS 2000 E
DEIMOS 2130 W
PHOBOS 2350 W

APR 02
PHOBOS 0340 E
PHOBOS 0730 W
PHOBOS 1115 E
DEIMOS 1235 E
PHOBOS 1510 W
PHOBOS 1855 E
PHOBOS 2245 W

APR 03
PHOBOS 0235 E
DEIMOS 0345 W
PHOBOS 0625 W
PHOBOS 1015 E
PHOBOS 1405 W
PHOBOS 1755 E
DEIMOS 1855 E
PHOBOS 2145 W

APR 04
PHOBOS 0130 E
PHOBOS 0525 W
PHOBOS 0910 E
DEIMOS 1000 W
PHOBOS 1305 W
PHOBOS 1650 E
PHOBOS 2040 W

APR 05
PHOBOS 0030 E
DEIMOS 0110 E
PHOBOS 0420 W
PHOBOS 0810 E
PHOBOS 1200 W
PHOBOS 1550 E
DEIMOS 1615 W
PHOBOS 1940 W
PHOBOS 2325 E

APR 06
PHOBOS 0320 W
PHOBOS 0705 E
DEIMOS 0725 E
PHOBOS 1055 W
PHOBOS 1445 E
PHOBOS 1835 W
PHOBOS 2225 E
DEIMOS 2230 WAPR 07
PHOBOS 0215 W
PHOBOS 0605 E
PHOBOS 0955 W
PHOBOS 1340 EDEIMOS 1340 E (Mutual)
PHOBOS 1735 W
PHOBOS 2120 E

APR 08
PHOBOS 0115 W
DEIMOS 0445 W
PHOBOS 0500 E
PHOBOS 0850 W
PHOBOS 1240 E
PHOBOS 1630 W
DEIMOS 1955 E
PHOBOS 2020 E

APR 09
PHOBOS 0010 W
PHOBOS 0355 E
PHOBOS 0750 W
DEIMOS 1100 W
PHOBOS 1135 E
PHOBOS 1530 W
PHOBOS 1915 E
PHOBOS 2305 W

APR 10
DEIMOS 0210 E
PHOBOS 0255 E
PHOBOS 0645 W
PHOBOS 1035 E
PHOBOS 1425 W
DEIMOS 1715 W
PHOBOS 1815 E
PHOBOS 2205 W

APR 11
PHOBOS 0150 E
PHOBOS 0545 W
DEIMOS 0825 E
PHOBOS 0930 E
PHOBOS 1320 W
PHOBOS 1710 E
PHOBOS 2100 W
DEIMOS 2330 W

APR 12
PHOBOS 0050 E
PHOBOS 0440 W
PHOBOS 0830 E
PHOBOS 1220 W
DEIMOS 1440 E
PHOBOS 1605 E
PHOBOS 2000 W
PHOBOS 2345 EAPR 13
PHOBOS 0340 W
DEIMOS 0550 W
PHOBOS 0725 E
PHOBOS 1115 W
PHOBOS 1505 E
PHOBOS 1855 W
DEIMOS 2055 E
PHOBOS 2245 E

APR 14
PHOBOS 0235 W
PHOBOS 0620 E
PHOBOS 1015 W
DEIMOS 1205 W
PHOBOS 1400 E
PHOBOS 1755 W
PHOBOS 2140 E

APR 15
PHOBOS 0130 W
DEIMOS 0310 E
PHOBOS 0520 E
PHOBOS 0910 W
PHOBOS 1300 E
PHOBOS 1650 W
DEIMOS 1820 W
PHOBOS 2040 E

APR 16
PHOBOS 0030 W
PHOBOS 0415 E
PHOBOS 0810 W
DEIMOS 0925 E
PHOBOS 1155 E
PHOBOS 1545 W
PHOBOS 1935 E
PHOBOS 2325 W

APR 17
DEIMOS 0035 W
PHOBOS 0315 E
PHOBOS 0705 W
PHOBOS 1055 E
PHOBOS 1445 W
DEIMOS 1540 E
PHOBOS 1830 E
PHOBOS 2225 W

APR 18
PHOBOS 0210 E
PHOBOS 0605 W
DEIMOS 0650 W
PHOBOS 0950 E
PHOBOS 1340 W
PHOBOS 1730 E
PHOBOS 2120 W
DEIMOS 2200 E

 

The Cyber-Myth That Just Won’t Die: See Mars as Large as a Full Moon!!!

It’s hard to believe that it’s been with us for a decade now.

Ten years ago this week, the planet Mars reached made an exceptionally close pass of the planet Earth. This occurred on August 27th, 2003, when Mars was only 56 million kilometres from our fair planet and shined at magnitude -2.9.

Such an event is known as opposition.  This occurs when a planet with an orbit exterior to our own reaches a point opposite to the Sun in the sky, and rises as the Sun sets. In the case of Mars, this occurs about every 2.13 years.

But another myth arose in 2003, one that now makes its return every August, whether Mars does or not.You’ve no doubt gotten the chain mail from a well-meaning friend/relative/coworker back in the bygone days a decade ago, back before the advent social media when spam was still sorta hip. “Mars to appear as large as the Full Moon!!!” it breathlessly exclaimed. “A once in a lifetime event!!!”

Though a little over the top, the original version did at least explain (towards the end) that Mars would indeed look glorious on the night of August 27th, 2003 … through a telescope.

Mars during the historic opposition season of '03.
Mars during the historic opposition season of ’03.

But never let facts get in the way of a good internet rumor. Though Mars didn’t reach opposition again until November 7th 2005, the “Mars Hoax” email soon began to make its rounds every August.

Co-workers and friends continued to hit send. Spam folder filled up. Science news bloggers debunked, and later recycled posts on the silliness of it all.

Now, a decade later, the Mars Hoax seems to have successfully made the transition over to social media and found new life on Facebook.

Mars as seen during a close conjunction with the Moon on July 17th, 2003. Mars was 20 arc seconds in size at the time leading up to the August 2003 opposition.
How Mars really appears next to the Moon: Mars as seen during a close conjunction with the Moon on July 17th, 2003. Mars was 20 arc seconds in size at the time, leading up to the August 2003 opposition. Image courtesy of Rick Stankiewicz, used with permission.

No one knows where the Mars Hoax meme goes to weather the lean months, only to return complete with all caps and even more exclamation points each and every August. Is it the just a product of the never ending quest for the almighty SEO? Are we now destined to recycle and relive astronomical events in cyber-land annually, even if they’re imaginary?

Perhaps, if anything there’s a social psychology study somewhere in there, begging the question of why such a meme as the Mars Hoax endures… Will it attain a mythos akin to the many variations of a “Blue Moon,” decades from now, with historians debating where the cultural thread came from?

Here are the facts:

-Mars reaches opposition about every 2.13 Earth years.

-Due to its eccentric orbit, Mars can vary from about 56 million to over 101 million kilometres from the Earth during oppositions.

-Therefore, Mars can appear visually from 13.8” to 25.1” arc seconds in size.

-But that’s still tiny, as the Moon appears about 30’ across as seen from the Earth. You could ring the local horizon with about 720 Full Moons end-to-end, and place 71 “maxed out Mars’s” with room to spare across each one of them!

-And although the Full Moon looks huge, you can cover it up with a dime held at arm’s length…. Try it sometime, and amaze your email sending/Facebook sharing friends!

Important: Mars NEVER gets large enough to look like anything other than a star-like point to the naked eye.

Reality check... how Mars really appears compared to the Moon as seen during a close conjunction in 2012.
Reality check… how Mars actually appears compared to the Moon as seen during a close conjunction in 2012.

-And finally, and this is the point that should be getting placed in all caps on Facebook, to the tune of thousands of likes…  MARS ISN’T EVEN ANYWHERE NEAR OPPOSITION in August 2013!!! Mars is currently low in the dawn sky in the constellation Cancer on the other side of the Sun. Mars won’t be reaching opposition until April 8th, 2014, when it will reach magnitude -1.4 and an apparent size of 15.2” across.

Still, like zombies from the grave, this myth just won’t die. In the public’s eye, Mars now shines “As big as” (or bigger, depending on the bad hyperbole used) as Full Moon now every August. Friends and relatives hit send, (or these days, “share” or “retweet”) observatories and planetariums get queries, astronomers shake their heads, and science bloggers dust off their debunking posts for another round. Hey, at least it’s not 2012, and we don’t have to keep remembering how many “baktuns are in a piktun…”

What’s a well meaning purveyor & promoter science to do?

Feed those hungry brains a dose of reality.

There are real things, fascinating things about Mars afoot. We’re exploring the Red Planet via Mars Curiosity, an SUV-sized, nuclear powered rover equipped with a laser. The opposition coming up next year means that the once every 2+ year launch window to journey to Mars is soon opening. This time around, the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission and, just perhaps, India’s pioneering Mars Orbiter Mission may make the trip. Launching from Cape Canaveral on November 18th, MAVEN seeks to answer the questions of what the climate and characteristics of Mars were like in the past by probing its tenuous modern day atmosphere.

The circumstances for opositions of Mars from
The circumstances for the oppositions of Mars from 2001 to 2029.

And as opposition approaches in 2014, Mars will again present a fine target for small telescopes.  As a matter of fact, Mars will pass two intriguing celestial objects next month, passing in front of the Beehive cluster and — perhaps — a brightening Comet ISON. More to come on that later this week!

And it’s worth noting that after a series of bad oppositions in 2010 and 2012, oppositions in 2014 and 2016 are trending towards more favorable. In fact, the Mars opposition of July 27th, 2018 will be nearly as good as the 2003 approach, with Mars appearing 24.1” across. Not nearly as “large as a Full Moon” by a long shot, but hey, a great star party target.

Will the Mars Hoax email enjoy a resurgence on Facebook, Twitter or whatever is in vogue then? Stay tuned!