Mercury Transit on November 8, 2006
News story originally written on November 6, 2006

The planet Mercury will cross in front of the Sun on Wednesday, November 8, 2006. Astronomers call the event a transit. A transit is like a solar eclipse. However, a transit occurs when a planet, instead of Earth's Moon, passes between the Sun and Earth. Planets are much further away than the Moon, so the planet does not completely cover the Sun during a transit like the Moon does during an eclipse.

Transits of Mercury happen about once every seven years on average. There will be 14 transits of Mercury this century. This one was the second. The last transit of Mercury before this one was on May 7, 2003. The next won't be until May 9, 2016.

Only two planets ever transit the Sun as viewed from Earth. The two planets are Mercury and Venus. All of the other planets orbit the Sun further from Earth and never pass between Earth and the Sun.

Transits of Venus are much rarer than transits of Mercury. Venus transits happen only twice per century. Maybe you saw the one on June 8, 2004. If not, the next transit of Venus is coming along in just a few years on June 6, 2012! Astronomers in the 1700's used transits of Venus to make the first good measurements of the distance between Earth and the Sun. They did that by carefully measuring the time of the transit from different places on Earth.

Last modified November 6, 2006 by Randy Russell.

You might also be interested in:

Transit

A "transit" is the name of a type of astronomical event. A transit is like a solar eclipse, when the moon blocks out the Sun. During a transit a planet, not the Moon, moves between Earth and the Sun. There...more

Mercury Transit on May 7, 2003

The planet Mercury appeared to cross in front of the Sun on May 7, 2003. Astronomers call the event a transit. A transit is like a solar eclipse. However, a transit occurs when a planet, instead of Earth's...more

Transits of Venus

Sometimes the planet Venus gets between Earth and the Sun. Astronomers call that a "transit" of Venus. A transit is a little bit like an eclipse of the Sun, when the Moon gets between Earth and the Sun....more

Venus Transit in June 2004

Astronomers are excited about a rare event that will happen in early June 2004. There will be a transit of the planet Venus on June 8, 2004. "Transit" is a word used by astronomers when a planet moves...more

History of Venus Transits

Sometimes Venus passes between Earth and the Sun. This event is called a transit of Venus. Transits of Venus don't happen very often. There is a pattern in the time between transits of Venus. The pattern...more

Mercury Transit on November 8, 2006

The planet Mercury will cross in front of the Sun on Wednesday, November 8, 2006. Astronomers call the event a transit. A transit is like a solar eclipse. However, a transit occurs when a planet, instead...more

More than 100 planets orbit distant stars!

Astronomers have identified another exoplanet, that is, a planet outside our solar system. This makes a total of 102 exoplanets that have so far been found by astronomers! The astronomers that identified...more

Map of the Sky

Thanks to a couple of telescopes, everyone on the internet can browse through almost 2 million images. Stars throughout the sky were photographed by the Two-Micron All Sky Survey (2MASS) and are now available...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA