Please (Again)– Mars Will NOT Look As Big As the Full Moon


I thought this year would be different and finally I could make it through the month of August without receiving a forwarded email from an excited acquaintance, wondering if I knew about this incredible news that will happen only once in a lifetime. The email claims Mars is coming closer to Earth and will look as big as the full moon!

Please, this is a complete falsehood and entirely not true. The email about this “once in a lifetime event” has been circulating like clockwork every August for the past five years and is full of errors. If you don’t believe me, here are Universe Today articles dubunking this erroneous email in 2007, 2006, and 2005. If you don’t believe Fraser, Phil Plait the Bad Astronomer debunks the email here, here , here, and here’s the original one back in 2003. I don’t know if the general public really is so uneducated/gullible/in the dark to fall for this every year, or if the folks who start circulating this email every year are trying to determine how uneducated/gullible/in the dark the world actually is.

This began in August 2003 when Mars actually did make its closest approach to Earth in the past 60,000 years. On August 27th, 2003, Mars was 55,758,006 kilometers (34,646,418 miles) away from Earth. Mars just looked like a bright “star” in the sky, not much different than how it usually looks to the naked eye whenever the two planets are at their closest approach. The view of Mars in a telescope was a little better than usual back in 2003, as the bigger telescopes could see the ice caps a little clearer, and possibly some other features. Someone got some bad information as to how big Mars would look at this closest approach and got excited about this bad information, then sent said bad information out in an email which spread like wildfire through the wonders of email forwarding.

This year in August, Mars is about 360 million kilometers (about 215 million miles) from Earth, not very close at all. Since Mars and the Earth are in different orbits around the Sun, and they each take different amounts of time to go around the sun (Earth 365 days, Mars 687 Earth days) the distance between the two planets grows and shrinks, with the closest approaches occurring about every 26 months. But the distance changes with every approach because of the way celestial mechanics works.

If you still need more info, NASA has a page debunking this email, too. Please, let’s work hard to let everyone know this Mars email is completely wrong so that we don’t have to write this article again next year.

44 Replies to “Please (Again)– Mars Will NOT Look As Big As the Full Moon”

  1. I did some calculations and the nearest that Mars could come to Earth (if the semi-major axes of their orbits lined up) is 54,571,299km. The farthest that the Moon can get from the Earth currently is 405,696km. This means that Mars would be at its closest 134.5 times farther away than the Moon at its farthest. So, for Mars to appear the same size as the moon, its radius would need to be 134.5 times as great as the Moon’s. The Moon’s equatorial radius is 1738.14km, so Mars would need to be 233,802km in radius. This is 36.66 times that of the Earth, and 3.27 times that of Jupiter, the largest planet in the Solar system. Mars, barring some very dramatic change in the orbits of the planets or of the Moon, will never appear as large as the Moon in the Earth’s sky. Math, internet people; L2math.

  2. Oh, a PS, for duh’s sake. Mars would need to be 68.84 times as large as it actually is.

  3. I do think people won’t ask this question anymore. But every year the same thing happen, even we already explain it is a hoax and they read the article clearly.. they still say.. let’s wait and see your article is right or not… or they would say… let’s wait for Mars .. and get proved about the hoax news….

  4. Here, in Buenos Aires, it´s happening the same. I can´t believe it! Every august 27 the same false story about Mars. It seems a lot of people have not memory at all

  5. If those spam emails aren’t promising a larger penis, they’re promising a larger Mars.
    Theres no winning with these guys.

  6. With 50 million deaths/year and 100 million births/year, I guess we’lll never get rid of gullible people…

  7. Yeah, I also had to crush this cockroach for the 4th or 5th time this year. Sheesh.

    What really bugs me is that the gullible don’t even try to get some actual info on their own. The web is crawling with debunking sites in every possible language, and yet this idiocy comes up again and again. Worse: it comes up with telltale signs that something is very wrong about it, like including the words “send this email to everyone you know”, blah blah blah. And yet the gullible swallow worm, hook and line. Every single year.

    It’s enough to shake one’s faith in the existence of intelligent life on this planet.

  8. There’s intelligent life on Earth? You’re kidding?

    There must be a spambot out there which pops these out automatically – surely no sentient being would be so brainless…

  9. I’ll go a step further and say that I’m not sure why Nancy posted this article in the first place. Far be it from me to alienate obviously un-knowledgeable individuals.. I would just like to have a hint of logic that supports any ………… I’m sorry…. What are they saying??…….

  10. here in egypt no one bleve this runmors although there’s no much people studies astronomy but when astronomers said that march well be closed to the earth many people asked if they could see it directly .
    when they heard that itwill be so far that it couldnt be seen with direct eyes and only the nearness between march and earth blow its top no more no one asked again as no one give care to space news .its ahuman happet that if you are waiting for something you bleaved every hint if you dont give care
    no problem let march het the earth .

  11. mustafa –
    I follow you..
    This is all about simple math and observations of the path (and past). I’m sure you know that.. I just wish others would..

  12. Be sure to call these misguided souls by the designated title of “idiot,” or “gullible” the next time you see them. That will surely win them over to reason and enlightened thought… Who will change their mind about Mars when someone with “scientific training” just called gullible and stupid? Whatever.

  13. “There must be a spambot out there which pops these out automatically – surely no sentient being would be so brainless…”

    Close – these messages are intentionally sent out there by people who wish to farm emails addresses. When it comes back around to them in the chain there are dozens of new email addresses in the header, which you can now instruct your spambot to send spam to.

  14. Forget trying to find intelligent out there in the Universe.
    Instead lets try to find some intelligent life right here on this miserable little silicone ball with carbon impurities.

  15. Folks – this is not so alarming. With so many really incredible true reports coming out of the scientific and astronomy communities, you need to be pretty sure of yourself to rule out this one.

    Think about it:
    – Water on Mars!
    – Gasers on a Jovian satellite!
    – Organic molecules in the cold reached of space
    – Underground water oceans
    – Hydrocarbon oceans
    and that’s just in our own back yard…
    How about:
    – Black holes and Quasars and Dark this and Dark that?
    – Light can be stopped!
    – Atoms can teleported!
    – Cloaking devices!

    So a layperson, not an idiot, not unitelligent, but also not a space hobbyist, can be forgiven for asking you about it.

  16. It would truly be a once-in-a-lifetime event should Mars appear in Earth’s skies as large as the full Moon. Once-in-everyone’s-lifetime, because tidal forces would tear both planets apart, killing everyone. Note to Hollywood: This is the perfect opportunity to remake “When Worlds Collide” without spending a lot of money on CGI.

  17. Ben, the problem with that reasoning is that a layperson who is not a space hobbyist would probably know about water on Mars, but would not know anything about any of the other stuff (the geysers are in a satellite of Saturn, BTW).

    A person able to think would also be able to take a step back and, well, think: “hm… I’ve never seen a disc on Mars with my own two eyes, however small it might be. How is it that it’s all of a sudden the size of the Moon? And they’re telling me to send this to everybody like one of those stupid chain mails? Hum… Fishy, very fishy. Let’s try to find out what’s going on here. Google… “moon the size of mars”. Ah, it’s a hoax. Figures.”

    The truth is that if a layperson believed in this 5 years ago it was one thing and quite excusable. After all, Mars was closer to Earth than usual back then. The next year, that layperson would begin to be a bit silly in believing this story, but what the heck, he could have sleped through the previous year. But now? Now only morons or amnesiacs can believe in this, quite frankly.

  18. “Once-in-everyone’s-lifetime, because tidal forces would tear both planets apart, killing everyone.” – Dave Burke.

    Not quite. I’m pretty sure that Mars at the apparent size of the Moon is still too far away for tidal disruption of either us or Mars.

  19. Jorge, stepping up the rhetoric to include “morons’ and “amnesiacs” with the original group, “idiots” really does not help your argument, or the cause of real science (which I thought was the goal of this website). There is such a thing as civility, and the idea of “rising above” the standard of your opponent. Again, who’s going to change their mind when you call them “moron,” “amnesiac” and “idiot?” They might as well go back to reading the National Inquirer…they’d at least get treated with more respect. But hey, what do I know. I’m defending morons, amnesiacs and idiots for the sake of advancing science. I guess I’ll go and start reading the Inquirer, too. At least I’d get a good laugh….which is a lot more than I can say after reading your comment.

  20. David, it depends.

    I have said and done some pretty idiotic things in the past, and as a consequence I have been called an idiot. Had I not been man enough to realise that the people calling me idiot then were right, then yes, I’d probably go read the Inquirer or any other dumb tabloid, probably not even realising that that kind of crap is way more disrespectful towards their readers than any foul-mouthed scumbag that calls them idiots in the face.

    Instead, I realised I was being an idiot, I was man enough to admit it, and I made sure to no be an idiot anymore… and least in that particular situation, for we can never know beforehand when and where idiocy strikes. My idiocy and other people’s insult led to enlightment, which is a good thing by any measure.

    It all depends on who you’re talking to, see? On how fragile is the ego of who you’re talking to.

    To be absolutely clear: nobody is an idiot for not being informed, now matter how stupid they might look at first glance. Asking stupid questions is a wonderful way to learn, and people should be encouraged to ask them. Therefore, for the first two or three iterations of the process, sure, things should be explained with all the patience of the world. But there’s a point where there’s no way a person with a working brain in the head will still believe in some stuff and patience simply drains out. This Mars thing has crossed that line already. Then it’s the time to try a different approach. And if as a consequence, after 5 years of people explaining it can’t be true and how and why it can’t be true, you still prefer to go read tabloids instead of paying close attention to who is calling you an idiot and explaining why you’re being an idiot, then you’re hopeless.

    And an idiot.

  21. Jorge,
    You are adept at making elaborate arguments while avoiding the original point. You think that name calling is a valid component of an argument. It isn’t (whatever the timeframe). Every book on rudimentary critical thinking/logic will point to the same conclusion. Your preference is to hold to your belief even though clear reasoning suggests otherwise. If we suspend the rules of basic logic and your argument is carried to conclusion, you meet your own definition of “hopeless” and “idiot.” Surely that isn’t what you mean…or is it? Inquiring minds want to know!

  22. Everytime this e-mail starts getting circulated, a co-worker of mine stops by to ask if I’m going to watch this exciting event. And every year for the pst three years I’ve had to tell her its bogus. Who keeps sending these things around, they’re driving me bananas!

  23. LOL! Boy, you are so predictable! I just knew you would not resist calling me an idiot. Puts your own ideas into perspective, doesn’t it? LOL! This is too funny. 😀

    Oh, boy. Thanks for the lough.

    Now, seriously. Look, think what you will, I couldn’t care less. But I daresay you are still not understanding.

    Let’s try to explain this to you following a different path.

    At this point, 5 years into this idiocy, all the critical thinking and logic has been tried to exhaustion. It has ran its course. It can’t go any further. Complicated matters can be reasoned around for centuries, but there are only so many ways in which you can explain simple things to people. Simple things such as this one. Everything has been tried since this thing started.

    When critical thinking and logic can’t go any further, you can do one of two things: you can give up, shrug and leave the argument. Or you can try to shake people into awakening. Some people are shakable into awakening, believe it or not. You seem to be too full of yourself to understand this, but different people do react differently to different stimula. Some need cuddling, some need a good shake. And those that can be awakened by a good shake will, after the early irritation ebbs away, be finally permeable to critical thinking and logic. And will probably understand. Finally.

    The others, well, you can cuddle them until the stars go dark for all I care.

  24. Jorge,
    Read the sentence again…slowly this time. Nothing there to say that I’m calling you an idiot, or any other adjective like stupid, defensive, or even simple minded. Nothing at all. Really. Nice try, but no, nothing there. I wouldn’t dare do that. Your faulty reasoning apparently has made you uncomfortable. And you still didn’t prove your original point, that name calling is a valid form of argumentation. You make other fine points about when enough is enough and so forth. But you never got back to proving the original point…

    It’s funny, I actually agree with the original premise of the story–the Mars story is terribly stupid. (Notice the key distinction between us–I call ideas stupid and you call ideas AND people stupid.) As to the rest of it, well, best idea you’ve had all day. I’ll go cuddle with the masses you suppose to be utterly hopeless while you go around and call them stupid whenever you subjectively and arbitrarily decide when they are in fact stupid. Of course, you never answered whether you were intending to include yourself in that grouping or if that was an oversight on your part…(notice again I didn’t call you anything) which may cause me to rethink my choice to cuddle with the masses.

  25. Well on Mars this time of year the Earth becomes larger than the sun, and makes many of us scared. We try to debunk this falsehood but some of us just never listen. Please help!

  26. Dear Mars Man,
    I will gladly offer my assistance. I will join you in debunking this idea. We will use reason, along with examples from math and physics. I will bring a steady supply of adjectives from Earth to include–like stupid, idiotic, moronic or just plain wrong. I will try to make sure that I apply these words to these wrong ideas. Others may arrive from my planet and may start using them, mistakenly, on the Martians themselves. I will take my flogging in advance.

  27. David…


    How many times have I to repeat that calling people stupid in this context is not intended as an argument, valid or not, but as a way to shake them until they wake the hell up and think? I’m sorry, but I don’t know how can I be any clearer than this. Maybe it’s my non-native english putting some kind of barrier here. I can’t say.

    Since this is the base of the argument you seem to be trying to build here, and you don’t seem to be capable of understanding its inherent falsehood, the building you try do build on this faulty foundation simply crumbles as buildings built on faulty foundations tend to do. What you call “my original point” exists only in your fertile imagination, and of course I won’t even try to prove a point I never tried to make. That would be… well… stupid. 😉

    But tell me something: do you dispute the existence of stupid people? How would you designate someone that keeps believing in stupid ideas, despite people explaining to him or her how and why those ideas are stupid? Over and over again? And over again? “Intellectually challenged”? Is this a question of politically correct semantics?

    Or is it simply a question of hypocrisy? You see, I know how to read between the lines. You don’t need to write plainly “you’re an idiot” to call someone an idiot. You can try to be subtle about it, clumsily or not, and still convey the message with the same cristal clear clarity. And if, while doing it, you say you’re not doing it, you’re being a hypocrite. Maybe you prefer hypocrisy. I don’t. For me, a hypocrite is a life form lower than an idiot.

    There’s worse, though: there are some that are hypocrites AND idiots.

  28. Jorge,
    However you state it doesn’t change the fact that you prefer to call people stupid. The only falsehood is yours. You fail to see your own faulty premise. That results in a faulty conclusion. You can dress it up however you wish with whatever issue you want, like trying to “shake people up” or misunderstanding me or whatever else. It does not change the fact that you resort to the lowest form of rhetoric (and I would not even extend you the courtesy of calling it rhetoric) by using simplistic, childish names. It is infuriating. It’s like making a blog site your personal playground where you go around and throw around a bunch of names at people. That is a stupid idea. Notice I didn’t call you stupid. I called your idea of disparaging someone to shake sense into them a STUPID IDEA.

    Which leads me to answering your question. Do I dispute the existence of stupid people? The question is moot. What I dispute is the idea of disparaging people for any reason. It is wrong, wrong, wrong. Ideas are wrong. People are wrong. That doesn’t mean we resort to name calling. You are wrong for calling people stupid. There is nothing between the lines. I am not being politically correct (an idea that I detest). It is a fundamentally stupid idea to go around and call people nasty names…especially on a website committed to truth, reason, and integrity. You are in bad form for doing so. When’s the last time you saw a NASA scientist in a public forum like this one call someone an idiot, stupid, etc?? Can you, for example, imagine Neal Armstrong going around to classrooms calling kids stupid because they believe Mars is as big as the moon? As a matter of fact, they used a turn-of-the-century form of the word “stupid” to describe young Einstein when he was a student. Give me a break.

    I don’t hold the slightest hope I will change your mind. But again, you will not win people over by calling them stupid. You lower your own integrity by doing so. There is a principal at stake. I am thoroughly disgusted by the name calling….and I will argue against doing so over and over, whether you get it or not. If I want to see this sort of thing, I can go to a chat room for immature pre-schoolers who don’t know any better. But I will continue to fight against it on a blog site as awesome as this one.

  29. However you state it doesn’t change the fact that you prefer to call people stupid

    Oh no, I don’t. I prefer to call people smart. I hate seing idiocies floating around me like flies. I much, much prefer to see people that think, that actually have ideas in their heads, instead of seing again and again and again the very same idiocies being blurted by people who only seem to have vaccum inside their skulls. Few things give me more pleasure than discussing stuff with smart people, and especially when I’m able to learn something in the process.

    You say that calling people stupid as a way to shake ’em up is a stupid idea. Fine. I kinda agree. It’s a stupid idea to call people stupid when they ask stupid questions… unless alternative ways to put some sense into their heads are exhausted. Unless facts have been explained to them (nicely) over and over and over and over again and they still fail to grasp them. Simple facts, so simple that you don’t even need to have finished highschool to be perfectly able to understand them. Like in this case.

    You may think even then that’s stupid. Also fine. It’s your opinion. I happen to have seen it work, though, so I know you’re wrong from personal, first hand experience. It doesn’t work for everybody, but some people do wake up. Some brains do benefit from this kind of quiskstart. Believe it or not. It does work sometimes. And as far as I’m concerned, that’s enough to make it worthwile.

    Breaking news, in case you hadn’t noticed: I’m not NASA ;). But yes, I have seen scientists calling stupid people stupid. Numerous times, in fact. Sometimes they shouldn’t, sometimes they go too far, but often that’s exactly what needs to be said. If NASA called a press conference and stated bluntly that enybody believing this Mars idiocy was an idiot that just might stop it once and for all. At the very least it would be so big news that you’d have to be a hermit not to hear about it ;). And some people might even try to understand why they were being so blunt about it, and in the process would learn something. If only to prove, to themselves and to others, that “no, no, I’m no idiot, I was just misinformed”.

    I happen to like PZ Meyers’ style. It pisses some people off, sometimes royally, but it actually enlightens others.

    You obviously don’t. And won’t, probably never, probably not even if you saw it working. So I’m shrugging and leaving the argument. It’s pointless.

  30. Yes it is pointless, shrug away. See you next time, and I’ll keep bringing up the same point over and over…anytime you decide to throw around the schoolyard antics. By the way, I’ve seen the EXACT OPPOSITE technique used on folks (NOT CALLING THEM CHILDISH NAMES), and that has worked splendidly, too. So if it’s down to an experiential claim, I’ll take mine, thank you. So shrug away, and I’ll keep fighting away. Disparagement has no place in a forum devoted to meaningful dialogue.

  31. Beware, you might become something worse than a childish schoolyarder: a stalker.

    (Yes, the exact opposite technique works too… who’s the idiot that said it didn’t? Until it reaches everybody it can reach, which is when my techique steps in. We’re complementary, you and I 😀 Much to your dismay and my amusement)

    Over and out.

  32. We need to stop looking to the stars to find intelligent life and start trying to find some here.

    I agree with early poster(s). Ignorance does not make someone an idiot.

    Willful ignorance (being told the facts and refusing to learn, or even just remember 1 year later) means you are an idiot. I don’t care what your IQ is, if you can’t remember what’s physically impossible after you’ve been made aware that it’s physically impossible, then you are an idiot because you lack common sense.

    There are two types of “smart” – book smart and smart enough to have common sense. If you don’t have the former you can still get by if you have the latter.

    But if you have only book smarts and no common sense you belong only behind the safe walls of academia. Leave the real world to people who can function in it.

    If you have neither you should not burden the gene pool by reproducing.

  33. Tyler,

    An interesting viewpoint that you share…and no doubt you’re in good company as far as the gene pool is concerned. I of course disagree with you. If I follow your reasoning (and I may not be able to, since I happily place myself among the genetically flawed) you seem to mix both Darwinism and subjectivity together. When I say Darwinism, I refer to your mention of the gene pool. When I say subjectivity, I refer to your comment regarding “book smart” versus “common sense.” I suppose IQ fits the bill of an objective standard (though many bright folks have fallen through the cracks of this measurement) but not really sure how in the world we would set an objective standard for “common sense.” Read up on a few postmodern thinkers who are shaping everything from science to religion and I believe you will see how your conclusion has at least indirectly been shaped by the philosophical trend of the day. Well, I’ve stuck my head out of the flawed gene pool enough for one day…time for me to return to the flawed slime from which I came. Ha.

  34. “but not really sure how in the world we would set an objective standard for “common sense.”

    I’m not proposing eugenics here. We don’t need a “common sense test.”

    I’m simply saying that people with neither common sense nor book smarts should choose not to reproduce. Why burden your offspring and eventually their offspring and so on?

    Unfortunately the effort to keep such genes out of the gene pool is pointless. The industrial revolution has invalidated survivial of the fittest. Now you need be neither wise, nor intelligent, nor physically fit to survive. The technology we have assures everyone will survive, whether fit or not, and reproduce.

    Darwin’s got to be rolling in his grave – the idiots have taken over.

  35. “The industrial revolution has invalidated survivial of the fittest. Now you need be neither wise, nor intelligent, nor physically fit to survive. The technology we have assures everyone will survive, whether fit or not, and reproduce.”

    Well, maybe not. In a pure or near pure capitalist society, we get something closer to “survival of the fittest.” Those who compete and are successful are rewarded while those that do not and are not receive the opposite. That potentially eliminates whole numbers from the gene poole, narrowing the field to those with last names like Rockefeller and Gates. One would assume that their success translates into smarter people. Unfortunately for you however, people with neither common sense nor book smarts will have the intelligence to stop reproducing. So our slime keeps mulitiplying much to the chagrin of those who have claimed to emerged from our special place. Hee hee haa haa. Back to the slime pit I must go. I must start copulating again.

  36. @Tyler Durden:

    “Darwin’s got to be rolling in his grave – the idiots have taken over.”

    Don’t worry, Fat Mike will save us.

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