There is some controversy (as usual!) on exactly how close Mars will get to Earth this month. Sky & Telescope magazine posted an interesting online article examining this problem: http://skyandtelescope.com/observing/objects/planets/article_970_1.asp
Here's a brief section of the article which states their conclusion: "Various different figures are being reported in different places; some are clearly wrong. Sky & Telescope sorted through the situation to find the authoritative answer. On August 27, 2003, at 9:51 Universal Time, the centers of Earth and Mars will be only 55,758,006 kilometers (34,646,418 miles) apart. The U.S. Naval Observatory�s MICA software and the Jet Propulsion Laboratory�s DE406 planetary ephemeris agree on this value for the true geometric distance." And note that although this is a US-based magazine (Cambridge, MA), they put km first [as all good astronomers would!] Here's some interesting related info I got in an email about this article: "Roger Sinnott, a senior editor of Sky & Telescope magazine, got to the bottom of the matter [of how long ago Earth and Mars were so close], finding 57,617 BC to be the correct date of the last Mars passage that came so close. That was 59,619 years ago (taking into account that there was no "year zero" between 1 BC and AD 1)." David Shatto Los Angeles On Thu, 7 Aug 2003 05:49:11 -0700 (PDT) M R wrote: > My friend sent an email about a Earth's close > encounter with Mars which has been circulating in the > internet. As usual, it is in miles > > I have just replaced with miles value with km value > and attached is the text, do forward this to your > friends & colleagues. > > CLOSE ENCOUNTER WITH MARS > ------------------------- > > Never again in your (or my) lifetime will the Red > Planet be so > spectacular This month and next Earth is catching up > with > Mars, > an encounter that will culminate in the closest > approach > between the two planets in recorded history. The next > time > Mars > may come this close is in 2287. Due to the way > Jupiter's > gravity tugs on Mars and perturbs its orbit, > astronomers can > only be certain that Mars has not come this close to > Earth in > the last 5,000 years but it may be as long as 60,000 > years. > The > encounter will culminate on August 27th when Mars > comes to > within 55,439,342 kilometers and will be (next to the > moon) the > brightest object in the night sky. It will attain a > magnitude > of -2.9 and will appear 25.11 arc seconds wide. At a > modest > 75-power magnification Mars will look as large as the > full > moon to the naked eye. Mars will be easy to spot. At > the beginning > of August Mars will rise in the east at 10 p.m. and > reach its > azimuth at about 3 a.m. But 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 > when it comes to seeing something that no human has > seen in > recorded history. So, mark your calendar at the > beginning of > August to see Mars grow progressively brighter and > brighter > throughout the month. Share this! No one alive today > will ever > see this again.
