Mars is NOT about to be the closest in 60,000 years.
Published on Jul 22, 2006 at 8:37 pm.
3 Comments.
Filed under skywatching.
Mars catches out attention. It has a distinctive color, every two years it is fairly close and bright, and it is named after the Roman god of war. Mars was found in the Nineteenth Century to rotate with about the same period as Earth, to have about the same tilt as Earth, and to have ice caps. It seemed like Mars might be habitable. In fact, that idea was so pervasive, that it was perfectly natural for people to readily accept the fanciful idea that Mars had canals on it. The canals were probably an optical illusion caused by poor seeing and wanting to see something. Anyway, with the stir over canals, H.G. Wells wrote his novel War of theWorlds. This really shook things up. Edgar Rice Burroughs followed with his John Carson of Mars books. Mars had caught the public attention. What a let down when astronomers showed that Mars is basically a dead world, with no liquid water on its surface, no creatures, no Martians, and there never were any Martians. Still, we are fascinated with Mars.
Mars’ orbit is much more elliptical than Earth’s orbit. Mars also takes a little under two years to make a complete orbit. So, about every other year or so, Earth passes Mars. At this time Mars is about as close as it can be to Earth. The actual date of passing is the opposition of Mars. Because both Mars and Earth have elliptical orbits, and the orbits sometimes bring the planets a smidgeon closer to one another a few days before or after opposition. The point at which the planets pass in their oribits changes. Interestingly, three years ago, in August 2003, Mars and Earth were passing the closest that they would be in 60,000 years. That was true, but they were only a very small fraction of a percent closer than they had been several decades earlier. In fact, Mars and Earth have a very close encounter (at least as far as planets go) every 15 or 17 years. The approach in 2003 was only a little bit closer than it had been 15 years earlier, and was only a tiny bit closer than it had been early in the Twentieth Century. Still, it was a record, and that was cool. We set up telescopes on campus and observed Mars at that time. Now, there were several email rumors going around about Mars at that time, and a couple got blown a bit out of proportion. One email said that with sufficient magnification in a suitable telescope, Mars could appear in the telescope’s eyepiece as large as the Full Moon appears in the sky to the unaided eye. Now, that is a convoluted statement, and it really doesn’t mean much to anyone who does not understand telescope optics. Technically, Mars can always be magnified in a telescope to appear as large as the Moon does without magnification. Few telescopes can do the trick though, most of the time. OK, so people had some unrealistic expectations in 2003, but it was still cool. So, in 2004, someone forwarded to me an email that someone had forwarded to them saying that Mars was going to be the closest to Earth that it had ever been in recorded history on “August 27 of this year.” The email went on to say that Mars would appear as large in the sky as the Full Moon (the whole part about using the telescope to magnify it to Moon size had been dropped from the email, apparently). I emailed back, “Sorry, but you missed it. That was August 27 of last year.” I also explained about the size thing, too. Then, I got a phone call, and another email, and so forth. People had dug up this old email and were sending it arournd. Sometimes it was the original email, and sometimes it was the new abbreviated (and incorrect one). Sadly, even the original one seems not to have the year 2003 in the email, just “this year” in the body of it. I gently told people what was up.
Then, last year, the same emails got going. I got an email from one of our librarians asking if it were true. Students asked me about it. I got phone calls. One of the weather forecasters here on a major local television station even said on the air that “later this week, on August 27, Mars will be the closest it has ever been to Earth and will appear in the sky as large as the Full Moon.”!!! She retracted the statement on a later newscast. However, I got tons of calls and emails from people asking if we were going to be setting up telescopes to see this event that they had heard about on the news. Well, last year, Earth did pass Mars again, as it does about every couple years. However, this time, we passed Mars in early November, and the closest approach was at the end of October. It was cool, actually. Since the day after the closest approach was October 30, the anniversary of the Orson Wells radio adaptation of H. G. Wells’ War of the Worlds. We did a Mars watch on that night. Mars was about several million miles farther from us in 2005 than it was in 2003, but still a good view.
Well, last night, I was with some people from my church, and what do you know, someone was talking about how she had just gotten an email that she had forwarded on to lots of her friends about Mars being the closest it had ever been in history and it being as big as the Full Moon next month on August 27. Nope. That is the same urban myth, recycling yet again. This is getting tiresome, now. I explained what was up. Even worse, Mars is on the far side of the Sun this August, so we won’t be able to see it at all. If we could, it would actually appear almost as small as it could possibly be given that it is just about as far as it can be from us!
This is one of those urban myths that never seem to go away. Somehow the internet seems to be a garden for these things. The ones that used to die off just keep going, and going, and going. Mary Jo recently posted a blog entry of her own on an urban travel myth that just seems to keep going and going. She has a good recommendation, something that I’ve been doing for years now. Before forwarding any of these email “news” things, or doing any action at all with them, check them out. I have found that most are false. There are a couple of good web sites for checking out urban myths and email hoaxes. One is Urban Legends and Folklore and the other is Snopes. Check both of them out. Sometimes one will catch an urban myth before the other one does. If everyone, or even a large number of people, would check these things out before mindlessly passing them along, then there would be a lot less useless stuff filling up our email inboxes.
-Astroprof
Astroprof’s Page » Mars still isn’t going to be spectacular this month. on August 9, 2006 at 10:20 pm: 1
[…] Wow. I realize that only a few people actually read my site (I would like to work to get more to read the new one here). But, on my old site, I posted a entry about the spectacular Mars urban myth going around. Well, it seems to have really taken off this year! This past week, someone forwarded me a really snazzy Powerpoint presentation about how Mars was going to be the closest to Earth in 60,000 years, and how it was going to appear as big as the full moon in the sky (it even showed the two side by side in the presentation. Well, it just isn’t going to happen. As I said before, Mars will be nowhere near Earth this August. And, even it were nearby, it would not appear to be remotely as big as the Moon with the naked eye. So, if you hear about this urban myth, don’t pass it on. What got me about this one, though, was that someone had gone to all the trouble to make such a snazzy powerpoint presentation. They even put the date listed as “August 27, 2006″. The original email going around for the last three years simply said “this coming August 27″ with no date. That is why I can understand at least a little bit why it keeps going. But someone went to the trouble of adding the year to this thing, but didn’t check to see if the information was accurate. That is what gets me. They put all this work into this presentation, which was really good artistically, by the way, but they didn’t bother to even do a little bit of checking to see if it were true. Interesting. It reminds me of how my students write their term papers. They do a quick Google or Yahoo search, take the first thing that looks good, and base their whole term paper off of that, without even a cursory check to see if it makes any sense at all. […]
Astroprof’s Page » Mars is Still Not Going to Appear as Big as the Moon!!! on August 9, 2007 at 12:41 am: 2
[…] Well, the annual urban legend about Mars being as big as the Moon is making an appearance again. I’ve already gotten several questions about it. This seems to be a never ending problem. Every year, the same email goes around as if it is news. I blogged about this a year ago. […]
RM1(SS) (ret) on August 15, 2007 at 2:59 pm: 3
nybody know how close Mars would have to be for it to really look the same size as the full moon?