Hobbies And Interests
Famous Historical Experiments
Galileo is famous for supposedly dropping two cannon balls of different weights from the leaning tower of Pisa, and discovering that regardless of mass they fall at the same velocity. With such a discovery, he became the first person to realize and tentatively estimate the effects of gravity at the Earth's surface. Johannes Kepler conducted experiments to explain planetary motions. By close observation of the orbits of the planets in the Solar system, particularly Mars, he finally confirmed not only Copernicus's theory that the Earth orbits the Sun, but that the planets move in ellipses rather than circles (See References 1 and 2).
Experimental Methods to Detect Planets Outside the Solar System
Scientists use a number of different techniques to detect extrasolar planets orbiting in other star systems, with the hope that they will one day discover other planets that house life. There are five different types of methods used to observe extrasolar planets: astrometry, in which scientists measure the wobble effected by the unobserved planet on its parent star, thus indicating the planet's presence; micro-lensing is a method which relies on observing the increase in luminosity effected by a planet-star system when it passes in front of a background star, where light is bent by the planet-star systems gravity; photometric transit method, measures the often tiny decrease in luminosity effected when a planet passes between the observer and its star; Doppler spectroscopy, also known as the radial velocity method is the most successful method for detecting extrasolar planets and involves the fact that a planet also exerts a gravitational effect on its star, meaning that as the planet comes between the star and the observer the luminosity will be blue-shifted, while it will be red-shifted when the planet is moving away; and, finally, direct detection, which has so far been the least successful method in observing extrasolar planets.
Experiments on Mars
With the development of rockets and spaceships, as well as robotic vehicles such as the Viking Lander, scientists are now able to conduct experiments in space. The primary objectives of the two Viking Landers was to get high resolution photos of the Martian surface. However, biology experiments undertaken on the surface have yet to yield any evidence of past or present life.
Future Planetary Experiments
NASA, ESA, and other space agencies continue to launch unmanned spaceships ever deeper into space to conduct experiments and feed back observations of planets in our solar system. Future missions include unmanned missions: the Juno mission to Jupiter, which aims to gain an insight into the Solar System's early history; the Mars Atmosphere and Volatile EvolutioN, which is due to explore the upper atmosphere of Mars; and the Curiosity Mars Science Laboratory, which is designed to explore the Martian surface for life. Space agencies are still committed to furthering manned space flights, and Mars is the next planet on the agenda.