Using Light to Learn About the Universe, Part 1
Scientists use light to study objects on Earth and beyond. In fact, it is because of light that astronomers can detect very distant objects in space.
Because most objects emit radiation across a wide range of wavelengths, scientists use different kinds of instruments to collect and analzye different forms of light. Telescopes are tuned to collect information at different wavelengths across the entire spectrum of electromagnetic waves. Spectrographs split light into an array of separate colors that can be used to infer the physical properties of objects.
Optical Telescopes
Optical telescopes detect light in the visible part of the electromagnetic spectrum. While astronomers still use large ground-based telescopes, space-based telescopes can offer much clearer views through space, as light is not impeded by Earth’s atmosphere.
The best-known optical telescope is the Hubble Space Telescope, which has returned breathtaking views of the cosmos, including some of the farthest galaxies ever seen. But another telescope, the Kepler Space Telescope, is producing remarkable work of its own by detecting the subtlest changes in the brightness of stars.
Watch this video, which explains how Kepler works. As you watch, note the details astronomers can infer about a planet from the light collected when a transit occurs.
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Video: How Does the Kepler Telescope Work?
Take Notes
- How does the Kepler Space Telescope use light to detect the presence of a planet and its size?
- Light makes a remarkable journey from far-away stars to telescopes like the Kepler. Which properties of light enable us to observe it over such great distances?
