Iridescence (also known as goniochromism) is generally known as the property of certain surfaces that appear to change color as the angle of view or the angle of illumination changes. Iridescence is commonly seen in items such as soap bubbles, butterfly wings, clouds, and sea shells.

Iridescence is an optical phenomenon of surfaces in which hue changes in correspondence with the angle from which a surface is viewed.

Iridescence is often caused by multiple reflections from two or more semi-transparent surfaces in which phase shift and interference of the reflections modulates the incidental light (by amplifying or attenuating some frequencies more than others). This process, termed thin-film interference, is the functional analog of selective wavelength attenuation as seen with the Fabry–Pérot interferometer.

The word iridescence is derived in part from the Greek word ἶρις îris (gen. ἴριδος íridos), meaning rainbow, which in turn derives from the goddess Iris of Greek mythology, who is the personification of the rainbow and acted as a messenger of the gods. Goniochromism is derived from the Greek words gonia, meaning angle, and chroma, meaning color.

Barack Hussein Obama II (ⁱ/bəˈrɑːk huːˈseɪn oʊˈbɑːmə/; born August 4, 1961) is the 44th and current President of the United States. He is the first African American to hold the office. In January 2005, Obama was sworn in as a U.S. Senator in the state of Illinois. He would hold this office until November 2008, when he resigned following his victory in the 2008 presidential election.

Born in Honolulu, Hawaii, Obama is a graduate of Columbia University and Harvard Law School, where he was the president of the Harvard Law Review. He was a community organizer in Chicago before earning his law degree. He worked as a civil rights attorney in Chicago and taught constitutional law at the University of Chicago Law School from 1992 to 2004. He served three terms representing the 13th District in the Illinois Senate from 1997 to 2004.

Following an unsuccessful bid against the Democratic incumbent for a seat in the United States House of Representatives in 2000, Obama ran for the United States Senate in 2004. Several events brought him to national attention during the campaign, including his victory in the March 2004 Illinois Democratic primary for the Senate election and his keynote address at the Democratic National Convention in July 2004. He won election to the U.S. Senate in Illinois in November 2004. His presidential campaign began in February 2007, and after a close campaign in the 2008 Democratic Party presidential primaries against Hillary Rodham Clinton, he won his party's nomination. In the 2008 presidential election, he defeated Republican nominee John McCain, and was inaugurated as president on January 20, 2009. Nine months later, Obama was named the 2009 Nobel Peace Prize laureate. In April 2011, he announced that he would be running for re-election in 2012.

James Roy Horner (born August 14, 1953) is an American composer, orchestrator, and conductor of orchestral and film music. He is noted for the integration of choral and electronic elements in many of his film scores, and for frequent use of Celtic musical elements. His score to the 1997 film Titanic remains the best selling orchestral film soundtrack of all time.

In addition, Horner has scored over 100 films, frequently collaborating with acclaimed directors such as James Cameron and Ron Howard. Some of his most noteworthy works include Star Trek II: The Wrath of Khan (1982), Star Trek III: The Search for Spock (1984), Cocoon (1985), An American Tail (1986), Aliens (1986), The Land Before Time (1988), Willow (1988), Glory (1989), Field of Dreams (1989), The Rocketeer (1991), Legends of the Fall (1994), Apollo 13 (1995), Braveheart (1995), The Mask of Zorro (1998), A Beautiful Mind (2001), Troy (2004), and Avatar (2009).

Horner has won two Academy Awards, two Golden Globe Awards, three Satellite Awards, three Saturn Awards, and has been nominated for three BAFTA Awards. His body of work is also notable for including the scores to the two highest-grossing films of all time; Titanic (1997) and Avatar (2009), both of which were directed by James Cameron.