Astronomers use a variety of tools to study space, and most of them are types of telescopes. Unlike the telescope you may have in your room for looking at stars, the telescopes used by astronomers are highly specialised. They are sensitive to specific types of light not normally visible to the human eye. "Astronomers can study objects that emit very little visible light...using telescopes that 'see' the forms of light our eyes cannot," states the Johns Hopkins University Spectroscope Fact Sheet.
Hubble Space Telescope
NASA and the European Space Agency's spaced-based Hubble Space Telescope has been floating in the vacuum since 1990. Because it orbits the earth, Hubble is immune to the distortion of light caused by the Earth's atmosphere. For this reason alone, it is an invaluable tool for the study of space. Since astronomers obtained its first captured images in 1990, the Hubble has enabled the discovery of dark energy and new planets, and advanced understanding of how planets form. "The HST has expanded our understanding of star birth, star death, and galaxy evolution, and has helped move black holes from theory to fact," says the Hubble Site.
A spectroscope is an essential tool for astronomers. Many astral bodies and events, such as pulsars, quasars and black holes, emit light on a spectrum invisible to the human eye. Yet studying this light allows scientists to deepen their understanding of the objects, and thereby space at large. Through the process of spectroscopy, astronomers use a spectroscope to separate different wavelengths of light and study them individually. According to Johns Hopkins University, "astronomers use spectroscopy to study properties of objects in the universe, besides chemical composition, such as the temperature, density, chemical composition and speed of a celestial object, and whether it is moving away from or towards us."
NASA partnered with the U.S. Department of Energy and institutions in France, Germany, Japan, Italy and Sweden in 2008 to launch the Fermi Gamma-Ray Space Telescope. Gamma-ray radiation is a tremendous, invisible source of energy emitted by super-massive black holes and merging neutron stars. "With Fermi, astronomers will...have a superior tool to study how black holes...accelerate jets of gas outward at fantastic speeds. Physicists will be able to study subatomic particles at energies far greater than those seen in ground-based particle accelerators. And cosmologists will gain valuable information about the birth and early evolution of the Universe," says NASA of the project.