Space Exploration - Section 3 Flashcards
What are the two types of optical telescopes?
Refracting
Reflecting
What is a refracting telescope?
Uses two lenses to gather and focus starlight
There is a limit to how large refracting telescopes can be
What are reflecting telescopes?
Use mirrors instead of lenses to gather and focus the light from stars
What is interferometry?
The technique of using telescopes in combination
What is the Hubble Space Telescope?
It is a reflecting telescope
Commands to the Hubble to preform different tasks are sent from ground control several times a day
What is wavelength?
A measurement of the distance from one point on a wave to the same point on the next wave
What is frequency?
The number of waves that pass a single point in one second
Energy with a ____ frequency has a ______ wavelength
High
Small
What is a radio telescope?
A telescope system that collects and analyzes radiation in the radio frequency range from stars and other bodies in space
What are the advantages of radio telescopes over optical telescopes?
Radio waves are not affected by weather and can be detected during the day and night
They are not distorted by clouds, pollution, or the atmosphere, as are light waves
Radio telescopes are typically made of mesh metal, whose shapes resembles a satellite dish
Because the wavelengths of radio waves are large the antenna must be large
What is radio interferometry?
Several small radio telescopes can be combined to achieve greater resolving power than one large radio telescope can achieve
The accuracy of measurement can be increased even further if more telescopes are arranged into groups called arrays
What are two ways of measuring distances on the ground and in space indirectly?
Triangulation and parallax
What is triangulation?
Is based on the geometry of triangle
By measuring the angles between a baseline and the target object, you can determine the distance to that object
What is parallax?
Is the apparent shift in position of a nearby object when the object is viewed from two different places
How do astronomers determine the elements that make up a star?
They compare a stars spectrum with the spectra of known elements, using a spectroscope to map the spectrum of a star
