Mars hoax
Encyclopedia
The Mars hoax was an e-mail
-circulated hoax
that originated in 2003, claiming that Mars
will look as large as the full Moon
to the naked eye on August 27, 2003. The hoax, which has since resurfaced in every year from 2005–2011, stemmed from a misinterpretation and exaggeration of a sentence in an e-mail message which communicated the close encounter between Mars and the Earth in 2003 in which the distance between the planets was 55,758,006 kilometres, the closest distance between the planets since September 24, 57,617 B.C when the distance is calculated to have been 55,718,000 km.
orbits round the Sun in approximately the same plane; by the nature of things the distance between them varies periodically from a minimum equal to the distance between their orbits at some point along them, to a maximum when they are on opposite sides of the Sun. These minimum (opposition) and maximum distances vary considerably as the two planets progress along their elliptical orbits, and occur about every 780 days. Mars was closer at the 2003 opposition than it had been since 57,617 BC, and than it will be until 2287 or possibly much later.
There was another opposition on 30 October 2005, but with a minimum distance about 25% greater than in 2003 (as reported in the original email, text below) and apparent diameter correspondingly smaller. The magnitude
was -2.3, about 60% as bright as 2003. (The Moon has an apparent diameter of around 30 minutes of arc, i.e., 1800 arcseconds, with magnitude of about -12.7 when full, about 9,000 times brighter than Mars in the 2003 approach.)
Although the e-mail itself is correct, the hoax stemmed from a misinterpretation of the sentence "At a modest 75-power magnification Mars will look as large as the full moon to the naked eye". The message was often quoted with a line break in the middle of this sentence, leading some readers to mistakenly believe that "Mars will look as large as the full moon to the naked eye" when, in reality, this sentence means that Mars enlarged 75 times will look as big as the moon unenlarged.
It is quite obviously scientifically incorrect that Mars, normally never more than a dot in the night sky, could suddenly become visibly large due to normal variations in orbit. If Mars did appear as large as the moon it would be so close that it would cause catastrophic gravitational effects—Mars has about twice the diameter of the moon, and hence would be about 2 times as far away for the same apparent size; it has 9 times the mass of the moon, and would have over twice the gravitational effect (9 times larger mass divided by relative distance (2) squared).
E-mail
Electronic mail, commonly known as email or e-mail, is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. Some early email systems required that the author and the recipient both be online at the...
-circulated hoax
Hoax
A hoax is a deliberately fabricated falsehood made to masquerade as truth. It is distinguishable from errors in observation or judgment, or rumors, urban legends, pseudosciences or April Fools' Day events that are passed along in good faith by believers or as jokes.-Definition:The British...
that originated in 2003, claiming that Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
will look as large as the full Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
to the naked eye on August 27, 2003. The hoax, which has since resurfaced in every year from 2005–2011, stemmed from a misinterpretation and exaggeration of a sentence in an e-mail message which communicated the close encounter between Mars and the Earth in 2003 in which the distance between the planets was 55,758,006 kilometres, the closest distance between the planets since September 24, 57,617 B.C when the distance is calculated to have been 55,718,000 km.
Background
Both Earth and Mars are in ellipticalEllipse
In geometry, an ellipse is a plane curve that results from the intersection of a cone by a plane in a way that produces a closed curve. Circles are special cases of ellipses, obtained when the cutting plane is orthogonal to the cone's axis...
orbits round the Sun in approximately the same plane; by the nature of things the distance between them varies periodically from a minimum equal to the distance between their orbits at some point along them, to a maximum when they are on opposite sides of the Sun. These minimum (opposition) and maximum distances vary considerably as the two planets progress along their elliptical orbits, and occur about every 780 days. Mars was closer at the 2003 opposition than it had been since 57,617 BC, and than it will be until 2287 or possibly much later.
There was another opposition on 30 October 2005, but with a minimum distance about 25% greater than in 2003 (as reported in the original email, text below) and apparent diameter correspondingly smaller. The magnitude
Magnitude (astronomy)
Magnitude is the logarithmic measure of the brightness of an object, in astronomy, measured in a specific wavelength or passband, usually in optical or near-infrared wavelengths.-Background:...
was -2.3, about 60% as bright as 2003. (The Moon has an apparent diameter of around 30 minutes of arc, i.e., 1800 arcseconds, with magnitude of about -12.7 when full, about 9,000 times brighter than Mars in the 2003 approach.)
Origin
The Mars hoax originated from an e-mail message in 2003, sometimes titled "Mars Spectacular", with images of Mars and the full moon side by side:Although the e-mail itself is correct, the hoax stemmed from a misinterpretation of the sentence "At a modest 75-power magnification Mars will look as large as the full moon to the naked eye". The message was often quoted with a line break in the middle of this sentence, leading some readers to mistakenly believe that "Mars will look as large as the full moon to the naked eye" when, in reality, this sentence means that Mars enlarged 75 times will look as big as the moon unenlarged.
It is quite obviously scientifically incorrect that Mars, normally never more than a dot in the night sky, could suddenly become visibly large due to normal variations in orbit. If Mars did appear as large as the moon it would be so close that it would cause catastrophic gravitational effects—Mars has about twice the diameter of the moon, and hence would be about 2 times as far away for the same apparent size; it has 9 times the mass of the moon, and would have over twice the gravitational effect (9 times larger mass divided by relative distance (2) squared).
Resurfacing
The hoax has resurfaced a number of times since 2003, and may continue to do so, always announcing an imminent close Earth-Mars approach. The content of the original email, although almost entirely correct for August 27, 2003, has falsely been redated to announce a new close Earth-Mars approach—the real close approach was in 2003 only—also misinterpreting the original e-mail by saying Mars will look as large as the moon. The later e-mails are incorrect, as Mars will not come as close to Earth as it did in 2003 until August 28, 2287 or later.External links
- Beware the Mars Hoax (NASA article from 2005)
- Snopes page on the Mars Spectacular
- Hoax Slayer article: Mars, Earth - Closest Approach in Recorded History
- Sky and Telescope Magazine: Mars Hoax Returns
- space.about.com: Mars Hoax Back Again
- BBC News: The perennial Mars hoax e-mail
- 2006 Mars Hoax Powerpoint Presentation
- MSNBC Video on the Mars hoax
- MSNBC Cosmic Log