1. And other technologies advance our understanding of space.
Telescopes
And other technologies advance our understanding of space.

2. Chris Hadfield Wet washcloth in space Check & Reflect
Page 439, #s 1-9 (Wed, May 25)
Page 445, #s 1-7 (Friday, May 27)
Page 454, #s 1-7 (Friday, May 27)

3. Look up into the cloudless night sky…
See a few thousand stars.
With binoculars, 10s of thousands.
Telescope… millions, and using the most powerful, billions.

5. Optical telescopes Light collectors
Series of lenses and mirrors gather and focus the light from stars so we can see them.
The larger the area of the lenses or mirrors in a telescope, the…???

6. The greater the ability of the telescope to see the faint light of objects that are very distant.

7. Refracting Telescope First telescope ever designed.
Limit to how large they can be.
Any lens over 1 m causes the glass in the lens to warp under its own weight.

8. Wisconsin, Yerkes Observatory
Largest refracting telescope in the world; weighs half a ton.

9. Reflecting Telescopes
Use mirrors instead of lenses to gather & focus the light from stars.
At one end of the telescope is a large concave mirror made from glass-like material that is coated wit a layer of metal.
Metal is polished to a shiny finish; can reflect the faintest light it receives.
Largest about 6m.

12. Interferometry
Technique of combining two or more telescopes in combination.
Resolution of images is better if 2 or more telescopes are used together.
In Hawaii, Keck I and Keck II are located 85 metres apart, and when working together, can detect objects in space better than other Earth- based observatories can.

13. Hubble Space Telescope
Offers a solution to the problems of light pollution, air pollution, clouds, rain, and high winds that interfere with star gazing.
Orbits about 600 kms above Earth; each orbit takes about 95 minutes.
Is a reflecting telescope.
Launched in 1999
Modular- so shuttle missions can replace faulty or out of date parts.

19. How do you throw up in space?
Video

20. Technology: Seeing beyond the visible.
Stars and galaxies also emit radio waves, infared (heat) waves, and X-rays.
These are all forms of electromagnetic energy.
This energy travels at the speed of light:
kms/s

21. Wavelength
Measurement of the distance from one point on a wave (such as the crest) to the same point on the next wave.

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

24. Electromagnetic Spectrum
The whole range of electromagnetic energy – what we see (visible light), and what we don’t (X-rays, etc.)

26. Inverse Relationship- one goes up, the other down.
Energy with a high frequency has a short wavelength (Gamma Rays, frequency: 1020, wavelength: less than a millionth of a centimetre).
Radio waves have a low frequency, but wavelengths that can be several kilometres long.

27. Radio Telescopes- studying radio waves not seen
Advantages: not affected by weather and can be detected day or night.
Not distorted by clouds, pollution, or atmosphere- like light waves are.
A large amount of matter in space emits no light- like neutral hydrogen- astronomers have been able to learn a lot about areas that seemed “empty”.

28. Radio Telescope
How we discovered that the shape of our galaxy, the Milky Way, is spiral.

29. Interferometry Radio Telescopes Look like satellite dishes.
Several radio telescopes can be combined to achieve greater resolving power (means give a clearer picture).
Interferometry

31. Viewing more than the eye can see…
Black holes and pulsating stars…
Huge bursts of gamma rays that appear without warning and then fade.

33. Space probes
Telescopes can’t provide answers to all the questions we have about our solar system.
Sample soil on Mars; land on Venus, and study Saturn’s rings.
Galileo designed to gather info on Jupiter’s atmosphere.
Mars Pathfinder soil samples & performed geological tests on planets rocks.

34. Physically Explored by Humans
Only the moon Apollo 11- brought back rocks, drove a buggy, took a few golf swings.
Next planned: Mars- up to 3 years and extremely dangerous.

35. Technology to measure distance:
We can’t tell how far away a star is just by looking.
Triangulation: based on the geometry of a triangle.
By measuring the angels between a baseline and and the target object (such as a tall tree or water tower), we can determine the distance of that object

38. Parallax
The apparent shift in position of a nearby object when the object is viewed from two different places.
Close your left eye, hold out your thumb and cover a spot opposite from you. Open your left eye and close your right eye.
Background of your thumb appears to have moved- that is parallax.

39. Astronomers…
Use a star’s parallax (shift in position relative to the background stars) to determine the angles to use when they triangulate the star’s distance from Earth.
Longest baseline we can use from Earth is the diameter of the Earth’s orbit- measurement must be taken 6 months apart to achieve maximum baseline length.

41. Peanut Butter Sandwiches in space
Video

42. What are stars made of? How do we determine their composition?
White light is actually a combination of all colours (the colours of the rainbow).
White light can be separated into its component parts by using a prism (shining light through a prism).
The result is bands of colour which are referred to as the visible spectrum.

44. Spectroscope
Instrument that determines the “fingerprint” of a star, and determines a star’s composition.
Various elements in a star absorb light in different ways, and starts have distinct sequences and thicknesses in their colour bands.

46. Doppler Effect

47. Emergency Vehicle Siren
Changes as it approaches, passes, and then moves away- that is the Doppler Effect
Sound waves are compressed in front of the vehicle as it approaches- pitch rises.
As it moves away, sound waves are no longer squeezed behind vehicle, and they stretch out- pitch falls.
Doppler Effect

48. Star’s Direction of Motion
Like sound, light also travels in waves.
Changes in light waves can be used to measure how fast, and in what direction, a light-emitting object is moving.
Another way the Doppler Effect is used- radar guns- emits a signal of a known wavelength. The car generates a returning wave- difference in 2 wavelengths show how fast the moving vehicle is travelling.

49. Astronaut Good job, but you have to drink your own pee
How do you poop in space?