Mars as big as the Moon: it's baaaaack

By Phil Plait | August 19, 2008 8:04 pm

Like a cold sore, a relative who won’t leave, or American Idol, the unwelcome "Mars is as big as the Moon" email is back once again to send nonsense into your mailbox.

First, the offending mail:

Two moons on 27th August

Mars as big as the Moon picture, showing Saturn’s moons

27th Aug the Whole World is waiting for………….

Planet Mars will be the brightest in the night sky starting August. It will look as large as the full moon to the naked eye. This will cultivate on Aug. 27 when Mars comes within 34.65M miles off earth. Be sure to watch the sky on Aug. 27 12:30 am. It will look like the earth has 2 moons.

The next time Mars may come this close is in 2287.

Share this with your friends as NO ONE ALIVE TODAY will ever see it again.

Now, the trashing:

THIS EMAIL IS NOT TRUE. It’s baloney, wrong, a lie, a con, a hoax, a joke, a falsehood.

Now, the specifics:

Oh, just go here and read about the last time I debunked this. Or the time before that. Or the time before that, or before that, or the original time back in 2000 and freakin’ 3.


Look folks, Mars is on the other side of the Sun right now. On the date indicated in the email (Aug. 27), it’ll be 360 million kilometers (about 215 million miles) from Earth. At its closest, Mars gets about 56 million kilometers (35 million miles) from the Earth, so this email is way, way off. Once again, like all the others before it (and all the ones to come, no doubt), they just keep replacing the date from last year’s hoax with the current date.

In this version, though, there are two new things that I love for their ever-increasing dumbosity. One is that the term is "culminate", not "cultivate". We’re not reaping Mars.

The other is the attached picture. It’s not Mars and the Moon. It’s two moons of Saturn. See the weird band shape along the bottom of the picture? Those are Saturn’s rings! This picture was taken by Cassini, the spacecraft orbiting the ringed giant world, currently well over 1.5 billion kilometers away.

So once again the bar has been lowered by email hoaxers. And still, I have to wonder, how many people will be fooled by it?

Tip o’ the spam filter to BABloggee David Roberts for being the first to send this to me.

CATEGORIZED UNDER: Antiscience, Astronomy, Debunking, Science

Comments (88)

  1. Blu-Ray-Ven

    make it stop, just make it stop. it never stops to amaze me how woowoo just goes round and round. and to make it worse, my dad believed this for a while till i straighted him up

  2. “This will cultivate”

    Culminate. CULMINATE.

  3. Bah, I swear when I skimmed your post you didn’t mention that. Teach me to not read carefully before replying.

  4. You really gotta wonder who sends this kind of crap around, and for what purpose. The notion that someone actually believes this is mind numbing, especially given all the previous times it’s been passed around. Yet it would stand to reason that the only way this kind of thing gets passed around is because someone actually does believe it.

    Hey Phil, this nonsense has has me wondering for a while now: just how close to Earth would Mars actually have to be to appear as big as the full moon? Dividing Mars’ diameter by the Moon’s diameter, I see that Mars’ diameter is approximately 3.1417 times the Moon’s, so Mars would have to be just 942,000 kilometers from the Earth to appear to have the same average angular size as the Moon.

    Is my reasoning correct, or is there anything I’m missing?

  5. You clearly get a better class of spam than I do.

  6. yeliabmit

    My understanding is that many — perhaps most — of these emails (and similar ones that aren’t just spamming porn sites or Viagra) are sent out into the wild to harvest active email addresses. People forward the message to others, who forward the forward, etc, and when it finally makes it back to a spammer’s email account, the headers are full of nice fresh email addresses for them to add to their databases.

  7. Todd W.

    So does that mean that on the 27th we will be able to see the face on Mars?

  8. It will never be clearer.

  9. Doesn’t the moon rise as a thin crescent at like 4 in the morning on 27 August?
    It won’t even be in the sky at 12:30.

  10. Lunar radius: 1737 km
    Mars radius: 3390 km

    The ratio is 1.95, not 3.14. So Mars has to be about twice as far as the moon.

    Actual distance ratio:
    Mars is 125-1000 times farther away, depending on orbital configuration.

  11. TomR

    The funny thing about this one is that you don’t need no fancy science or nothing to debunk it…just look up, for jeez sake!

    Sad thing, that people are so removed from something as basic as the night sky that you can tell them there’s another moon up there.

  12. BA:

    And still, I have to wonder, how many people will be fooled by it?

    Based on the number of questions on the subject over at Yahoo Answers, the answer is “plenty”. (Though at least they’re asking things like “is this true?” as opposed to just “spreading the word”. Perhaps there’s hope yet? Hopefully, they’ll listen to the “it’s a hoax/fake/lie” answers they get.)

  13. Thanks Lab Lemming. I see the problem was that I must have been using miles for the Moon and kilometers for Mars. The answer is, more or less, 586,191 kilometers or 362,000 miles.

    It’s somewhat surprising to me that it would have to basically be another moon to look like the Moon. I think I understand now why people can find this myth believable: without having actually done the calculations, it’s not intuitive to grasp that a whole planet would have to be so close just to take up such a tiny amount of space on the sky.

  14. The original email said that through a telescope at 75x, Mars will look as big as the Moon does by eye. That much of it, originally, was true.

  15. RickJ

    I’ve been sent this by a neighbor. Each year he sends me one of these asking “Is this true?” Each year I tell him it isn’t true nor can it ever be true but he keeps asking and apparently hoping it will be true. He also seems to believe anything he reads on the internet. How he survives I don’t know. In the version he sent me the Cassini image was a link to a mild Yahoo erotic website!

    Note too the piece taken out of each moon at about 4 o’clock. The original doesn’t have this.


  16. I got this email hoax forwarded to me by my 90 year old mother last year and the year before that. I carefully and as nicely as possible crafted an astronomically correct response and sent it to all the addresses on the forwarded email.

    I also got the “God’s Eye” Helix Nebula hoax through her and did the same thing there. I got a reply back from a man in Florida who said “There’s always some ***hole who wants to spoil the fun!” Go figure! Apparently ignorance is not just bliss, it’s fun…

    Now that my mom has passed away I probably won’t get these hoax emails anymore.

    So here is my idea.
    We make our own hoax, only it’s not a hoax, it’s viral science.
    Circulate this to all your friends:
    Planet Mars will be the brightest in the night sky starting on these dates:

    Jan 29, 2010 – 61.72 million miles from Earth
    Mar 03, 2012 – 62.62 ” ” ” ”
    Apr 08, 2014 – 57.41 ” ” ” ”
    May 22, 2016 – 46.78 ” ” ” ”
    Jul 27, 2018 – 35.78 ” ” ” ”
    Oct 13, 2020 – 38.57 ” ” ” ”

    It will look as large as the full Moon to the naked eye only if you use a telescope to view Mars and the naked eye to view the Moon.

    So use a telescope!

    On these dates Mars will rise as the Sun sets as it’ll be 180 degrees opposite it in the sky.

    As you can see we come near Mars every 2 years 1 month. Mars has an orbit that is a little elliptical so it orbits closer to the Sun at one point on its orbit.

    This part of its orbit is on the same side of the Sun where Earth has Summer in the Northern Hemisphere. Since our close approaches to Mars creep around the calendar, Mars will come closer over the years till the 2018 apparition. Then it’ll drift back out again as the years progress.

    Mars has 2 moons, but they’re very tiny and very, very hard to see, even with a large telescope.

    Mars is still a cool planet to see because we can actually see its surface details, not cloud tops like all the major planets.

    Share this with your friends as NO ONE ALIVE TODAY will ever be able to say you’re not the coolest for knowing these facts!

  17. antaresrichard

    It appeared in my inbox a few days ago, so I just Emailed my friend all your posts on the subject back to 2003. I’ve no doubt the meme will be back come next July or August.

  18. kuhnigget

    Perhaps there’s hope yet? Hopefully, they’ll listen to the “it’s a hoax/fake/lie” answers they get.

    I doubt it. My mom sends me the latest incarnation of this crap every year. Remember the shot of the “Columbia” being hit by meteors, as photographed by an Israeli spy satellite? Sigh.

    Every time she forwards one of these things I send back a link to Snopes or some other site where the b.s. is clearly revealed, but it never seems to help.

    What I keep trying to communicate, and what unfortunately she doesn’t seem to get, is how much cooler the real science is (like the stuff AstroBum posted up there!) compared to the fake crap.

    Someone should do a study as to why a photograph of “god’s eye” is more appealing to these people than a photo of “a star that’s blown off its atmosphere.”

  19. Nemo

    I got a reply back from a man in Florida who said “There’s always some ***hole who wants to spoil the fun!”

    That really is appalling, but I guess I shouldn’t be surprised. Clearly many people do (unjustly) see this sort of thing as more “fun” than reality.

    As for the hoax itself, as stupid as it is, maybe it’s a good thing, if it gets people looking up at the night sky.

  20. Daniel

    In my book Mars is really not good enough for a prank email like this (Its been overhyped since sojurner). I wonder if Saturn or Jupiter would be a better choice.

  21. Richard Drumm The Astronomy Bum Says:”I got a reply back from a man in Florida who said “There’s always some ***hole who wants to spoil the fun!” ”

    The clear impression I get from this (I’ve received similar comments) is that you hadn’t debunked it, it would have happened.

    Like others above, I’m the family debunker and when my relatives send all of this drek through our “” I always reply with the Snopes link.

    I’ve noticed a lot of these spams now are about some item that Snopes has declared to be “partially true” or “true in the past” (e.g. viruses that now every program catches). The spam includes the breathless “SNopes says IT’s ture!!!1!”, hoping, I suppose, that no one will actually check the link.

    – Jack

  22. Don Snow

    My present browser screens and keeps out all spam.

    Back in ’03, I can remember this hoax going around; my writing a debunk; and clicking “Reply to All”.
    I also sent emails to my friends, asking them to first research these things, before mailing them to everybody. I can’t remember that helping.

    I think these things are mailed out, and passed around for the human love of gossip. Or love of big roller coaster: they get a safe and cheap scare from the hoax.

    That’s my best guess.

  23. You’d think that after they go outside a few times and it doesn’t happen, they’d figure it out.

    – Jack

  24. Francois

    I got actually asked the other day, by somebody who got the email if this was true. At least the questioned the posibilty and asked me about it. But sadley we had a lunar eclips this weekend and no world wide emails went out about that or I was just not on the mailing list, but did get to see it here down is South Africa.

  25. “when Mars comes within 34.65M miles off earth.”

    I initially read that as 34.65 miles (as perhaps Phil did, too, judging from his comments about being not even close?) Then I saw the M.

    I just realised – as this hoax appears to be getting dumber every year, it’s quite clear what will happen next year – they WILL drop the M and thus claim that Mars will be hovering 34 miles overhead.

  26. When are the twin moons of Uranus coming around?

  27. LB

    This hoax is revived just to annoy Mr BA here, knowing that he will forcefully debunk the message again 😉

  28. Todd W.

    I send my relatives to the snopes site, too. It actually seems to have worked, as the number of hoax e-mails I get has plummeted. Now I just get glurge where it doesn’t even matter whether or not the e-mail is true, it’s just “such a good message”.

  29. Todd W.


    You’re the one that started it up again, aren’t you?

  30. Thank you for this information,I would like to watch this two moons.Mars will look as large as the full moon to the naked eye. By the end of August when the two planets are closest, Mars will rise at nightfall and reach its highest point in the sky at 12:30 a.m. That’s pretty convenient to see something that no human being has seen in recorded history.

  31. Grand Lunar

    I knew almost immediately that the photo was that of Saturn’s two moons seen by Cassini.

    It seems these emails target those that are ignorant in astronomy and do not practise critical thinking.

    We should spread emails that promote critical thinking and skepticism.
    Can it be done?

  32. Nigel Depledge

    I, too, recognised the Cassini picture, although I cannot recall which two moons are in the image (maybe Enceladus and Mimas?).

  33. Michelle

    That’s pretty much a running gag by now. I doubt that whoever writes these is serious about it.

  34. Charles

    The US’s appalling lack of science education sets the table for emails like this, because people simply do not know better. Add a heaping double-helping of movie and television science fiction to fortify the ignorance and you have a veritable feast of stupid.

    The best part, to me anyway, is when people call me a smart-a** know-it-all because I shoot down these things and point out the sheer folly of it all. I usually tell them that I am smart enough to realize that I don’t know much at all, and that admitting as much is a sign of intelligence.

  35. The first version I got of this, in 2003, was actually correct. The text had the nuance that Mars would look about the size of the moon when Mars was viewed through a moderate-quality telescope. Of course, deleting the telescope part makes the whole thing much more sensational…

  36. firemancarl

    I love sending emails like this one back. With all the debunking info of course!

  37. Anyone here seen “Idiocracy”? First of all it’s got electrolytes! Second, the devolution of this Mars/moon-hoax reminds me of the movie’s future vision of Starbucks…

  38. PG

    [movie trailer voiceover]Just when you thought it was safe to look up at night…[/voiceover]

    I work at a university. Every year I get a call from someone asking me about this.

    [voiceover]The email that would never die it back for another round…[/voiceover]

    @Lars: Yep. “Is there anyplace I can get some water?” “You mean- like from the TOILET?” :)

  39. Brian Schlosser, Lurker

    Auguust 27th is my birthday (along with LBJ, Mother Teresa, Pee-Wee Herman and Yassar Arafat…talk about a party!), so every year, according to the Internet, Mars is as big as the MOON! I’m the luckiest boy in the world!

  40. The guy who said “There’s always some ***hole who wants to spoil the fun!” was the navigator on my pilot father’s crew for a flight in WWII across South America that crashed due to his navigational negligence. This might explain why he’s such a dingaling.
    It’s better to be a smart*** than a dumb*** I always say.
    (I wonder if I can say dumb@$$ and get away with it…)

    OK, how did you do it? What are the HTML image tags you used? Inquiring minds want to know!

    I -DO- hope you’re kidding us. You appear to be a gullible dupe, though. Have you even read Phil’s blog entry at all? You link to a real astronomy blog in the UK, but seem to have little astronomical knowledge. What’s up?

  41. Oh that’s rich! It thought that was an email address!

  42. E-mail makes it all too easy to forward junk to everyone. In the old days, you had to put a stamp on a chain letter. Now with a single mouse click you can transmit idiocy to as many contacts as you like.
    Fortunately, most people I send debunking messages to appreciate the correction – I now have a reputation at work as the guy who “corrects” email woo. Some people have even learned to think twice about sending these things out. Some people never learn though.

    My concern about this type of stooopidity is that it has a subtle and insidious effect. It purports to be about “sciency things”, and then when it doesn’t happen, it is actually “science” that takes a blow to the reputation. Sad but true.

  43. Andy Beaton

    So from the picture, I gather that not only will Mars be a big as the moon, but Saturn’s ring will be as big as the Milky Way! That will be a show worth seeing.

    And Michael L. – thanks for keeping my blood pressure up with the “Uranus” jokes :-)

  44. tom

    Maybe I’m lucky so far, but I haven’t received any emails to our astronomy club yet asking “what time will it be closest, and will you have a Mars viewing?”
    This email just proves how stoopid most of humanity really is.

    I was once at a garage sale a few years back and was wearing my Mars rover t-shirt. Someone complimented me on it and I said “Amazing they are still running isn’t it?”…thinking I found someone that “gets it” – wrong.
    “Oh, I thought they had returned to earth already?”


  45. Kate


    I’m pretty sure Emily is just being Poe-esque, Poe-ish… whatever…

    After all, the line: Isn’t it convenient to see something… seems to be a play on the horrible wording in the original e-mail.

    At least, I hope that’s the case.

  46. IBY

    No way, it can’t be baloney. The internet says so. The internet is always right. Phil must be working for NASA to cover it all up. 😉

  47. Ian

    Hey, I wonder if this is the reason they chose August 27 to air the MythBusters moon hoax episode.

  48. PG

    I think the Aug 27th date actually refers to the date several years ago when Mars and Earth were the closest to each other and closer than they would be for several thousand years. That’s when this email started, and that where the “no one alive today will see it again” line came from. Every year since then, I get this email and they don’t even both to change the date (even though the date of closest approach does change every year, but how can we expect them to know that?).

  49. At it’s current distance of over 200 million miles or 360 million kill-oh-meters 😉 wouldn’t Mars have to be two times larger (!) than the Sun in order for it to appear to our eyes as large as the moon does?

  50. IVAN3MAN

    Richard Drumm The Astronomy Bum:

    OK, how did you do it? What are the HTML image tags you used? Inquiring minds want to know!

    I found out how to use HTML tags in Wikipedia — a great source of information! — and the syntax that I used for the above cartoon image is:

    *img src=”” alt=”image name” /*

    N.B. Replace the “*” with the “” tag at the end.

    Obviously, I could not use the actual tags in the above example, so as not to confuse this web-site’s computer!

  51. gopher65

    I think that Phil sends these emails around himself in order to make sure he has material for his blog! That’s the only explanation!11!!eleven!!!!

  52. Nemo


    The best part, to me anyway, is when people call me a smart-a** know-it-all because I shoot down these things and point out the sheer folly of it all.

    It’s like they take pride in being ignorant. [/obama]

  53. Sili


    Hmmm? Just a Cupertino or could it be an eggcorn (not that I can imagine a reänalysis that fits)? Perhaps just and oldfashioned typo.

  54. Chris A.

    I attribute the herpes-like permanence of this hoax to two things:

    1) A shocking lack of fundamental astronomy knowledge, akin to believing that Moon phases are caused by the Earth’s shadow on the Moon, or that seasons are caused by the Earth’s varying distance from the Sun. I have coined a term for this malady: “inasteracy” (inspired by John Allen Paulos’ term “innumeracy” for its mathematical analog).

    2) Outright intellectual laziness. It’s easier to spread the gobbledygook than it is to take thirty seconds to do some research. The evidence for this, as others have intimated, is that there are some people who, no matter how many times you point them to Snopes, will continue to forward this dreck without a moment’s pause, let alone a few keystrokes and some reading. It’s the same disease afflicting many (most?, all?) evolution deniers; it’s too much work to try and understand the evidence (“Some of it is _complicated_! It makes my poor little brain hurt! Waaah!”), so we’ll just pretend it doesn’t exist or brush it off with plausible-sounding (but ultimately flawed and/or deliberately deceitful) arguments.

    Sorry. I’ve been in a bit of a mood lately over the 2012 woos, et al.

  55. @ Andy Beaton,

    That’s the oldest but best joke about Uranus… :)

    I mean how many jokes have you heard about Uranus… :)

    I guess it depends on how big Uranus is… :)

    Ok, I’ll stop now, but it wasn’t my idea to name a planet after Uranus… :)

  56. Nostradamus

    I predicted in Quatraine #83 that Phil would debunk this on more than one occasion. That said, for some reason I can’t see past the year 2012…what’s up with THAT?

  57. psychman

    I am from Nigeria and have just purchased Mars. Due to Nigerian laws, I cannot export Mars. If you would send me a money order for $2500, however, I could ship Mars to you!!!

  58. Law Mom

    I get all the woomail, and am also considered the no-fun know-it-all if I point people to snopes.

    One time my secretary sent me the one about nutrition and cancer that was supposedly from Johns Hopkins. Five seconds on snopes debunked that one. Her response was, and I quote, “I would like to know what makes this ‘snopes’ web site so credible??”

    Oh, the irony.

  59. kuhnigget

    @ Law Mom:

    I can top that! When our dog was diagnosed with cancer, my sister in law sent me that fake Johns Hopkins email, and she highlighted the parts about going vegetarian, having one or two alcoholic drinks a week, doing Tai Chi, etc.

    I can’t quite picture a Welsh Corgi doing Tai Chi, but I sure as hell don’t want him slamming vodka shots when I’m not looking…

  60. ND

    Law Mom,

    Been there. Even when when the facts are presented sympathetically and without trying to sound like you’re saying “haha you’re an idiot” many people will react irrationally. They have invested belief in the spammed rumor and an realizing it is not a good feeling.

    But still the best policy is politely pointing things out, AND not reacting irrationally oneself when faced with correct facts. Politeness and a fair reputation goes a long way.

    That said, I can completely understand the cynicism, frustration and the desire to grab them and shake them until they get it :)

    It took me several times of responding with references to snopes to get relatives to not automatically believe in spammed rumors. This includes those lottery scams. At least one has stopped sending me such emails because she realized I’m not buying them. I wish she would continue to email me because she’s still into astrology and new age crap.

  61. AJ

    “Chris A. Says:
    August 20th, 2008 at 11:58 am

    I attribute the herpes-like permanence of this hoax to two things:

    1) A shocking lack of fundamental astronomy knowledge, akin to believing that Moon phases are caused by the Earth’s shadow on the Moon, or that seasons are caused by the Earth’s varying distance from the Sun.”

    Yeah… I was disabused of that second one in primary school, aged 10. I think I’d heard that the Earth was sometimes further from the Sun, you see, so it seemed to make sense at the time… then we had a lesson on Earth & astronomy.

    Now, if I was taught this at 10 years of age, you have to ask yourself this: what exactly is wrong with the education system, that such basic things are just not understood by so many people?

  62. Nemo

    I was disabused of that second one in primary school, aged 10. I think I’d heard that the Earth was sometimes further from the Sun, you see, so it seemed to make sense at the time… then we had a lesson on Earth & astronomy.

    Heh — at the age of 12, I disabused my “teacher” of that one. He was more like a glorified coach, and it was social studies class, but still…

  63. Most people just don’t appreciate how small Mars is- As I mentioned above, it is less than twice the diameter of the moon.

    Now, if you replaced Mars with Jupiter, then oppositions would look a bit cooler. Jupiter is 41 times wider than the moon, so at a perihelial opposition, (125 times as far), Jupiter would appear to be about 1/3 the diameter of the moon.

    Of course, doing this would destabilize the orbit of the Earth, but let’s not dwell on the details here…

  64. Rock on, Richard. I like your email much, much better!

  65. That’s a cool thought, Lab Lemming! I’ll have to remember that one for public outreach teachable moments.
    Rich in Charlottesville

  66. Jose

    Do you know what would stop all these email hoaxes? A five cent tax on every email sent. I’m writing my congressman, Tony Schnell (R), immediately.

  67. Darrin Cardani

    Also, why is the picture dithered to 1 bit? We’ve seen some beautiful images from Cassini, so it seems odd that this one would have originally been a 1-bit per pixel image.

  68. Rebel

    I have to laugh at the fact that they all contain the “no-one alive today will see this again.” Since this email comes out every year or so, does that mean that we are all living through a couple of hundred of years in just one or two years?

    Do these people not remember that they supposedly could have seen the same thing last year, and that it did not happen?

    I got one acquaintance to stop sending me those spam emails about lost children by constantly sending him links to snopes.

  69. IVAN3MAN

    Just reply to the spam “Mars as big as the Moon” e-mail(s) with: You’re talking out of Uranus!

    Sorry, I just had to say it!

  70. Buzz Parsec

    Oooh, the stoopid! It tastes like BURNING.

  71. Neal Hughes

    I just asked people when they posted this on our local birdcage liner’s forums, “Don’t you think we would have seen it coming by now?” and “My gosh! Think of the tides if it gest that close to earth!”
    I was made out to be a spoil sport and then when I got hate mail, told them, “It is pouring down tonight — be sure to stay out all night in the rain watching the two moons in the sky!”

  72. Kyle

    wow. so when are we gonna see Pluto? maybe it will come about 1 km away from us! Maybe in about 2 years! :)

  73. LiberalGeeks
  74. Ashamed to have been fooled

    Well, as my name says, I too was fooled, at least for a moment. Sadly that moment resulted in me blurting out the “Good news” to my youngest son….then qualifying it with a “Well, I have to check first”. The reason most of us are fooled by this is because many of us are fascinated with the stars, the planets, and everything else in the sky. However, many of us also do not have the astronomical education to know any better. Simply, as was demonstrated by my gullible blurting, we seek to share that wonder with those around us, because truly, the universe is amazing. If you take the logic and the facts out, wouldn’t you be THRILLED to find out this “news”. Also, the email itself has been updated, it is now a PowerPoint presentation, the wording has been corrected (culminate, instead of cultivate) and the picture has been changed to one that shows Mars on the left and the Moon on the right (my assumption is that it is ‘photoshopped’). So it’s much more cleverly crafted than the originals, and more likely to find people willing to forward it to “All their friends and family”. (No I did not, I checked first and found this site. I’m an IT Professional, so I almost always check these types of emails, and only forward once the claims have been verified. But, again, even I was fooled, if only for a short while…

    Thanks for setting me straight and helping me avoid quite a bit of embarrassment.

  75. Alex Parratt

    I live in utah and a few days ago i saw that mars was as big as the moon


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!


See More

Collapse bottom bar