Science Topic 3.0: Optical Telescopes, Radio Telescopes And Other Tech For Space

Question 1

Optical telescopes

Answer 1

They have been in use for the past 400 years. In 1608, Hans Lippershey made one of the first telescopes, but it was Gallileo who has been credited with first using the telescope to study the visible features of the night sky.
They are known as light collectors… That is what their series of lenses and mirrors do- gather and focus the light from stars so that we can see it. The larger the area of the lenses or mirrors in a telescope, the greater the ability to see faint and distant light from space

Question 2

Refracting telescope

Answer 2

This was the first telescope ever designed and was very simple. They used 2 lenses to gather and focus starlight. There is a limit to how large of refracting telescope can be. They need to be a certain diameter so then the glass in the lens does not warp under its own weight

Question 3

Reflecting telescopes

Answer 3

Use mirrors instead of lenses to gather and focus the light from stars. At one and there is a large concave mirror. The metals such as aluminum that is that coats the lens, is polished to a shiny finish so that it can reflect the faintest light it receives

Question 4

New innovations with telescopes

Answer 4

They use a method called spin casting to form the largest mirrors… The process is quicker and less costly than previous methods of making reflecting mirrors
One of the newest innovations for ground based reflecting telescopes is the use of segment mirrors ( uses several lightweight segments to make one mirror) it results in an enormous light gathering ability and resolving power
Another is interferometry

Question 5

interferometry

Answer 5

A technique of combining the observations of 2 or more telescopes to produce images that have better resolution than what one telescope alone could produce

Question 6

Hubble space telescope

Answer 6

Orbits about 600km above earth
It is a reflecting telescope and launched in 1990.
It is a modular design that allows shuttle mission astronauts to replace faulty or out of date instruments on the telescope without having to interrupt other operations
It sends data to earth from its observations and can switch data transmission modes and the commands are sent from ground control several times a day.

Question 7

Electromagnetic energy

Answer 7

Optical telescopes give us info based on visible light, however objects in space, such as stars and galaxies, also emit radio waves, infrared waves, and X-rays which are a form of electromagnetic energy
It travels at the speed of light but has different wavelengths and frequencies from those of light

Question 8

Wavelength

Answer 8

The measurement of the distance from one point on a wave (such as the crest) to the same point on the next wave

Question 9

Frequency

Answer 9

Is the number of waves that pass a single point in one second

Question 10

Visible light spectrum

Answer 10

A part of the electromagnetic spectrum and is the only part that humans can see with their own eyes
Has a wavelength measured in micrometers

Question 11

Radio telescopes

Answer 11

Radio waves are received from stars, galaxies, nebulae, the sun and even some planets both in our solar system and in others
Astronomers have gained several advantages with radio telescopes over optical ones
Radio waves are not affected by the weather and can be detected 24/7
They have been able to map the distribution of neutral hydrogen in our galaxy… This is how they learned that it is a spiral galaxy
Radio telescope interferometry makes it more efficient to get clear radio images

Question 12

Space probes

Answer 12

Unmanned satellites or remote controlled landers used to explore areas or objects in space that are too difficult or dangerous to send humans to

Question 13

Triangulation

Answer 13

Is based on the geometry of a triangle
By measuring angles between a baseline and the target object, you can determine the distance to that object
You draw a scale diagram and use your protractor to measure two angles and find the unknown distance between

Question 14

Parallax

Answer 14

The apparent shift in position of a nearby object when the object is viewed from 2 different places

Astronomers use parallax to determine what angles to use when the triangulate the stars distance from earth
The longer the baseline, the more accurate result when triangulation calculations are made (use earths orbit for the longest baseline) you have to base your time over months to achieve the max length

Question 15

Visible spectrum

Answer 15

White light can be seperate a into its component colours by being shone through a prism… The result is bands of colour which together are the visible spectrum

Question 16

Spectroscope

Answer 16

Am instrument used by astronomers to observe and measure the spectrum of a star
They compare the spectrum of a star with known spectra of elements to determine the stars composition

Question 17

Doppler effect

Answer 17

The apparent change in frequency of sound, light and other waves as the observer and the wave source move towards or away from each other, also referred to as the Doppler shift

Question 18

Doppler effect to determine the moving of stars

Answer 18

Like sound, light travel in waves. changes used to measure how fast and in what direction a light-emitting object is moving
Pitch refers to the shift in sound waves of a moving object
The position of the dark hands in the light spectrum is what shifts in the light waves of a moving star
The spectrum of an approaching star shows the dark lines shifting to blue as the wavelengths compress (moving towards earth) the dark lines turn red as they move away from earth because the wavelengths stretch out.
It shows the speed at which a star is approaching or receding through this spectrum