transit Transit may refer to: Arts and entertainment Film * ''Transit'' (1979 film), a 1979 Israeli film * ''Transit'' (2005 film), a film produced by MTV and Staying-Alive about four people in countries in the world * ''Transit'' (2006 film), a 2006 ...

of Earth across the Sun as seen from Mars takes place when the planet

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

passes directly between the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

and

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...

, obscuring a small part of the Sun's disc for an observer on Mars. During a transit, Earth would be visible from Mars as a small black disc moving across the face of the Sun. They occur every 26, 79 and 100 years, and every 1,000 years or so there is an extra 53rd-year transit.

Conjunctions

Transits of Earth from Mars usually occur in pairs, with one following the other after 79 years; rarely, there are three in the series. The transits also follow a 284-year cycle, occurring at intervals of 100.5, 79, 25.5, and 79 years; a transit falling on a particular date is usually followed by another transit 284 years later. Transits occurring when Mars is at its

ascending node An orbital node is either of the two points where an orbit intersects a plane of reference to which it is inclined. A non-inclined orbit, which is contained in the reference plane, has no nodes. Planes of reference Common planes of refere ...

take place in May, those at descending node happen in November. This cycle corresponds fairly closely to 151 Mars orbits, 284 Earth orbits, and 133

synodic period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets, ...

s, and is analogous to the cycle of transits of Venus from Earth, which follow a cycle of 243 years (121.5, 8, 105.5, 8). There are currently four such active series, containing from 8 to 25 transits. A new one is set to begin in 2394. The last series ending was in 1211.

View from Mars

No one has ever seen a transit of Earth from Mars, but the next transit will take place on November 10, 2084. The last such transit took place on May 11, 1984. During the event, the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

can almost always also be seen in transit, although due to the distance between Earth and Moon, sometimes one body completes the transit before the other begins (this last occurred in the 1800 transit, and will happen again in 2394).

View from Earth

A transit of Earth from Mars corresponds to Mars being perfectly uniformly illuminated at

opposition Opposition may refer to: Arts and media * ''Opposition'' (Altars EP), 2011 EP by Christian metalcore band Altars * The Opposition (band), a London post-punk band * '' The Opposition with Jordan Klepper'', a late-night television series on Com ...

from Earth, its phase being 180.0° without any defect of illumination. During the 1879 event, this permitted

Charles Augustus Young Charles Augustus Young (15 December 1834 – 4 January 1908) one of the foremost solar spectroscopist astronomers in the United States. He observed solar eclipses and worked on spectroscopy of the Sun. He observed a solar flare with a spec ...

to attempt a careful measurement of the oblateness (polar compression) of Mars. He obtained the value 1/219, or 0.0046. This is close to the modern value of 1/154 (many sources will cite somewhat different values, such as 1/193, because even a difference of only a couple of kilometers in the values of Mars' polar and equatorial radii gives a considerably different result). Much more recently, better measurements of the oblateness of Mars have been made by using

radar Radar is a detection system that uses radio waves to determine the distance ('' ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, we ...

from the Earth. Also, better measurements have been made by using artificial satellites that have been put into orbit around Mars, including '' Mariner 9'', ''

Viking 1 ''Viking 1'' was the first of two spacecraft, along with '' Viking 2'', each consisting of an orbiter and a lander, sent to Mars as part of NASA's Viking program. The lander touched down on Mars on July 20, 1976, the first successful Mars la ...

'', '' Viking 2'', and Soviet orbiters, and the more recent orbiters that have been sent from the Earth to Mars.

In science fiction

science fiction Science fiction (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel uni ...

short story published in 1971 by Arthur C. Clarke, called "Transit of Earth", depicts a doomed astronaut on Mars observing the transit in 1984. This short story was first published in the January 1971 issue of ''

Playboy ''Playboy'' is an American men's Lifestyle magazine, lifestyle and entertainment magazine, formerly in print and currently online. It was founded in Chicago in 1953, by Hugh Hefner and his associates, and funded in part by a $1,000 loan from H ...

'' magazine.'Transit Of Earth' by Arthur C. Clarke read by himself
16 October 2017.

Dates of transits

Grazing and simultaneous transits

Sometimes Earth only grazes the Sun during a transit. In this case it is possible that in some areas of Mars a full transit can be seen while in other regions there is only a partial transit (no second or third contact). The last transit of this type was on 30 April 1211, and the next such transit will occur on 27 November 4356. It is also possible that a transit of Earth can be seen in some parts of Mars as a partial transit, while in others Earth misses the Sun. Such a transit last occurred on 26 October 664, and the next transit of this type will occur on 14 December 5934. The simultaneous occurrence of a transit of Venus and a transit of Earth is extremely rare, and will next occur in the year 571,471.

References

Albert Marth Albert Marth (5 May 1828 – 6 August 1897) was a German astronomer who worked in England and Ireland. Life After studying theology at the University of Berlin, his interest in astronomy and mathematics led him to study astronomy under C. A ...

, ''Note on the Transit of the Earth and Moon across the Sun’s Disk as seen from Mars on November 12, 1879, and on some kindred Phenomena'',

Monthly Notices of the Royal Astronomical Society ''Monthly Notices of the Royal Astronomical Society'' (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics. It has been in continuous existence since 1827 and publishes letters and papers reporting orig ...

, 39 (1879), 513–514

* Andrew Crommelin, ''Observations of Mars, 1904–6'', Monthly Notices of the Royal Astronomical Society, 64 (1904), 520–52

* Jean Meeus & Edwin Goffin, ''Transits of Earth as Seen from Mars'', Journal of the British Astronomical Association, 93 (1983), 120–12

*

, ''Measures of the Polar and Equatoreal Diameters of Mars, made at Princeton, New Jersey, U.S.'', The Observatory, 3 (1880), 47

*
SOLEX

External links

* ttp://ssd.jpl.nasa.gov/?horizons JPL HORIZONS System
Near miss of the Earth-moon system
(2005-11-07) {{DEFAULTSORT:Transit Of Earth From Mars Earth from Mars Earth Mars