Four-leaf clover

"Lucky clover" and "lucky leaf" redirect here. The term is also often used for the wood-sorrel Oxalis tetraphylla, a common potted plant.

For the popular 20th-century song, see I'm Looking Over a Four Leaf Clover. For the 2007 Second Person song, see Four Leaf Clover (song). For the 2010 Diana Vickers song, see Songs from the Tainted Cherry Tree.

Four-leaf clove

A four-leaf clover

The four-leaf clover is an uncommon variation of the common, three-leaved clover. According to tradition, such leaves bring good luck to their finders, especially if found accidentally. According to legend, each leaf represents something: the first is for hope, the second is for faith, the third is for love, and the fourth is for luck.

Clovers can have more than four leaves: the most ever recorded is fifty-six, Discovered by Shigeo Obara of Hanamaki, Iwate, Japan, 10 May 2009.

It has been estimated that there are approximately 10,000 three-leaf clovers for every four-leaf clover; however, this probability has not deterred collectors who have reached records as high as 160,000 four-leaf clovers. It is debated whether the fourth leaflet is caused genetically or environmentally. Its relative rarity suggests a possible recessive gene appearing at a low frequency. Alternatively, four-leaf clovers could be caused by somatic mutation or a developmental error of environmental causes. They could also be caused by the interaction of several genes that happen to segregate in the individual plant. It is possible all four explanations could apply to individual cases.

Researchers from the University of Georgia have reported finding the gene that turns ordinary three-leaf clovers into the coveted four-leaf types. Masked by the three-leaf gene and strongly influenced by environmental condition, molecular markers now make it possible to detect the presence of the gene for four-leaves and for breeders to work with it. The results of the study, which also located two other leaf traits in the white-clover genome, were reported in the July/August 2010 edition of Crop Science, published by the Crop Science Society of America.

The other leaf traits, the red fleck mark and red midrib, a herringbone pattern that runs down the center of each leaflet in a bold red color, were mapped to nearby locations, resolving a century-old question as to whether these leaf traits were controlled by one gene or two separate genes.

White clover has many genes that affect leaf color and shape, and the three in the study were very rare. These traits can be strikingly beautiful, particularly if combined with others, and can turn clover into an ornamental plant for use in flower beds.

Certain companies produce four-leaf clovers using different means.[citation needed] Richard Mabey alleges, in Flora Britannica, that there are farms in the US which specialize in four-leaf clovers, producing as many as 10,000 a day (to be sealed in plastic as "lucky charms") by feeding a secret, genetically-engineered ingredient to the plants to encourage the aberration (there are, however, widely-available cultivars that regularly produce leaves with multiple leaflets – see below). Mabey also states that children learn that a five-leaved clover is even luckier than a four-leaved one. Five-leaf clovers are less commonly found naturally than four-leaf clovers; however, they, too, have been successfully cultivated.

Other plants may be mistaken for, or misleadingly sold as, "four-leaf clovers"; for example, Oxalis tetraphylla is a species of wood sorrel with leaves resembling a four-leaf clover. Other species that have been sold as "four-leaf clovers" include Marsilea quadrifolia.

There are some cultivars of white clover (Trifolium repens) which regularly produce more than three leaflets, including purple-leaved T. repens 'Purpurascens Quadrifolium' and green-leaved T. repens 'Quadrifolium'.

Trifolium repens 'Good Luck' is a cultivar which has three, four, or five green, dark-centered leaflets per leaf.

References in popular culture

Marsilea quadrifolia is one of the answers to a crossword puzzle intricately connected to the plot of an AMC show named Rubicon, season 1 episode 1. In episode 3, this answer gains significance when it appears written on an index card along with only a small subset of other words from the puzzle. Futurama episode "Luck of the Fryrish" centres around a 7-leaf clover found by Fry. The clover had a very important role in Fry's early life, as well as Fry's brother, Yancy, and his son's lives.

The English-language imageboard website "4chan" has the Four-leaf clover as a part of their logo.

Source: en.wikipedia.org

Huge alien planet has a mysterious hot spot

A huge alien planet has a strange hot spot on its side, and astronomers aren't sure what to make of it.

The planet, named Upsilon Andromedae b, is a so-called "hot Jupiter" a scorching gas giant. It is also tidally locked, meaning that one side is perpetually boiling under its parent star's fierce glare.

But the warmest part of the planet isn't this sun-baked face, according to a new study. A spot way over on the side of the planet is actually much hotter. 

"We really didn't expect to find a hot spot with such a large offset," said lead author Ian Crossfield, of the University of California, Los Angeles, in a statement. "It's clear that we understand even less about the atmospheric energetics of hot Jupiters than we thought we did."

Measuring light from faraway planets

Upsilon Andromedae b is about 44 light-years from Earth in the constellation Andromeda. The planet is about 70 percent as massive as Jupiter, and it whips around its star every 4.6 days or so, scientists said.

Crossfield and his team used NASA's infrared Spitzer Space Telescope to measure the total infrared light coming from the planet and its parent star over five days in February 2009.

The Spitzer telescope cannot see the planet directly, but it can detect light variations that arise as the hot side of the planet comes into Earth's field of view. The hottest part of the planet will give off the most infrared light.

Conventional wisdom suggests that the star-planet system should appear brightest when the planet is directly behind the star, thus showing Spitzer its full sun-facing side.

But the system was brightest when the planet was to the side of the star, with its side facing Earth meaning that Upsilon Andromedae b's hottest parts are not under the star's full glare.

Observations of other hot Jupiters have shown that hot spots can be shifted to the side a little. Astronomers think that fierce winds may push hot gases around on such alien planets. But the new study found such a dramatic offset that other mechanisms are likely at work on Upsilon Andromedae b, scientists said.

Researchers have guessed at some possibilities, including supersonic winds triggering shock waves that heat material up, as well as star-planet magnetic interactions. But these are just speculation. As more hot Jupiters are examined, astronomers will test new theories.

"This is a very unexpected result," said Michael Werner, Spitzer project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., who was not involved in the study. "Spitzer is showing us that we are a long way from understanding these alien worlds."