Flashcards in Space Science Set 1 Deck (33)
What is astronomy?
Astronomy is the study of everything that exists beyond the earth, and is really the study of light
What does the word astronomy mean?
Astron means star and nomos means law
What is a telescope?
A telescope is a tool that makes far away things look up-close and bright.
Who is credited with building the first telescope in 1609?
Galileo Galilei, however many people had been building the knowledge for many years before.
Who actually built the first telescope?
Hans Lippershey in 1608, but Galileo improved his design.
Why did Galileo become so famous?
He promoted his ideas and also found Jupiter's largest moons.
In 1923, what did Edwin Hubble do?
Edwin Hubble use the most powerful telescope on earth at the time to find the Andromeda Galaxy.
Although astronomers knew about Andromeda Galaxy, how did Hubble add to their knowledge?
Hubble measured how far away Andromeda is, 10 times further away than the edge of our galaxy.
What did Hubble's discovery lead to?
Astronomers realized the universe was much bigger than they had thought and confirmed the existence of other galaxies.
What are the two types of telescopes?
Refracting telescopes and reflecting telescopes
How do refracting telescopes work?
Refracting telescopes bend (refract) incoming light through a tube to a focal point.
What are the two types of lenses in a refracting telescope?
An objective lens at the front through which light comes through first and an eye piece which magnifies the image.
How does a reflecting telescope work?
a reflecting telescope uses mirrors to reflect light to a focal point.
What are the mirrors in a reflecting telescope?
A primary mirror is a big curved mirror at the back that starts to focus the light, and the secondary mirror is a smaller mirror at the front that redirects the light towards your eye. There is also an eye piece lens.
Which type of telescope is better?
each one has advantages and disadvantages depending on what you want to look at.
What do most modern observatories use?
Most modern observatories use reflectors because the telescopes are so huge.
What is aperture?
Aperture is the diameter of the opening on the front. The bigger the aperture the more light enters the telescope
Why do telescopes need large apertures?
Telescopes need large apertures because the starts only give off dim light, so the aperture needs to be large to let in as much light as possible.
What is focal length?
Focal length is the length from the aperture to the focal point in the telescope.
What happens as the focal length gets longer?
The longer the focal length the smaller the patch of sky you can see, but the greater the magnification.
Why do reflecting telescopes have an advantage when it comes to focal length?
Refractors bend the light down the tube, the tube has to be at least as long as the focal length, but in reflecting telescopes the mirrors reflect the light so the tube can be shorter.
Why is aperture not so important to most astronomers?
Most planets are visible using a small telescope, and the moon is too bright if your aperture is too large. Even a small 20 cm telescope can see hundreds of galaxies and nubulae.
What is a galaxy?
A galaxy is a large system of stars, gases, and dust
What is a nebulae?
A nebulae is an interstellar cloud of dust and hydrogen gas, some are 100 million miles away
Why are astronomical cameras handy?
An astronomical camera can detect if a galaxy has a spiral centre and can give you precise data.
What is a spectroscope?
A spectroscope works like a prism and allows the camera to pick up small changes in colour.
What do the different colours in a spectroscope image show you?
A spectroscope image shows you different colours or different wavelengths of light.
What is the entire spectrum of light called?
The entire spectrum of light is called the electromagnetic spectrum EMS
Which light has the longest wavelength?
Red has the longest wavelength