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No Specific Date
Greek Philosophers ponder the existance of worlds other than Earth.
"There are infinite worlds both like and unlike this world of ours. We must believe that in all worlds there are living creatures and planets and other things we see in this world."
-Epicurius 300 B.C. -
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No Specific Date
Nicolaus Copernicus becomes the very first modern astronomer. He suggests that there are other planets apart from the Earth that orbit the Sun.
"Finally we shall find the sun himself at the center of the universe."
-Nicolaus Copernicus -
No Specific Date
Galileo Galilei in first introduces the telescope to the astronomy field. Galileo uses his own invention to observe the moons of the planet Jupiter, giving the proof that there are worlds besides our own.
"Besides the Moon, this spyglass has allowed me to see a multitude of fixed stars never before seen."
-Galileo Galilei, 1610 -
No Specific Date
William Herschel discovers the planet Uranus, the very first planet discovered since the ancient times.
"I have looked further into space than any human being did before me."
-William Herschel -
No Specific Date
Edwin Hubble proves that galaxies are groups of stars, similar to the Milky Way, by using the Hooker 100'' Telescope in California.
"Our sun is one of 100 billion stars in our galaxy. Our galaxy is one of billions of galaxies populating the universe."
-Werner Von Braun -
No Specific Day
The Hubble Space Telescope is launched. The telescope's primary mission is to later aid the identification and the study of exoplanets. The process to discover an exoplanet is to search for a dimming of light when a believed exoplanet passes between us and the planet's star.
"Such a scientic tool, if practically feasible, could revolutionize astronomical techniques and open up completely new vistas of astronomical research."
-Lyman Spitzer Jr., 1946 -
No Specific Date
The Planet PSR B1620-26 b is found orbiting a binary system that is composed of a pulsar and a white dwarf. This planet is located 1,170 light-years from earth. This planet is also about two and a half times the size of Jupiter (1400 earhts could fit in Jupiter) and takes 100 earth years to complete a single orbit.
"We therefore believe that PSRb1620-26 is likely to be either the first... binary star system with a planet."
-S.E. Thorsett, Z. Arzoumanian, J.H. Taylor, 1993 -
No Specific Date
Research teams led by David Charbonneau and Greg Henry independently speculate a planet passing in front of the star HD 209458. This transit method of observation will be further used to analyze the different atmospheres of exoplanets.
"We stand on the threshold of a new era of exploration and discovery... a better way to detect new worlds in our own Milky Way Galaxy."
-Dimitar Sasselov, 2003 -
No Specific Date
Astronomers from Geneva University find a planet named HD 28185b. This planet orbits the same distance similar to the Earth to the Sun. This planet is six times the size of Jupiter. The 'habitable zone' is an area in orbit where liquid water can exist.
"The planet around HD28185 is the first to be discovered around a middle age solar type dwarf, in a circular orbit, and located in the habitable zone where temperatures like those on the Earth are possible."
-N.C. Sanyos, 2001 -
No Spedific Date
NASA's Spitzer Space Telescope discoveres water vapor in the spectrum of the planet HD 189733b. This detection is the very first time water has been detected on an exoplanet.
"We... have identified clear signs of water on a planet that is trillions of miles away."
-Giovanna Tinetti, 2007 -
The hunt for exoplanets still continues today with great excitement. The great discovery of an exoplanet so much similar to our Earth could just be right around the corner.
"If we can identify another Earth-like planet, it comes full circle, from thinking that everything revolves around our planet to knowing that there are lots of other Earth's out there."
-Sara Seager, 2008 -
