1. Ch. 26.1 Viewing the Universe
Marques Notes – Earth Space Science

2. The Universe Astronomy – Scientific study of the universe
Used to:
Learn about Earth’s origin
Be able to benefit humans (EX: better energy source & protection from catastrophes)
Cosmology – Study of the origins, properties, processes, evolution of the universe.
Universe began ~ 13.7 billion years ago
It has been expanding faster & faster
Our Solar System is part of the Milky Way Galaxy – but beyond there are billions of other galaxies!

3. So… How was this picture taken?

4. Milky Way from Earth
Astronomical Unit (AU) – is the average distance between Earth & the Sun
Equal to ~ 150,000,000 kilometers!
Light Year – Alternate unit to measure astronomical distance
Distance between light travels in one year (light travels 300,000 m/s)
Approx TRILLION kilometers
* Closest star to earth (besides the Sun) is Proxima Centauri (~ 4.2 light years away)

5. Electromagnetic Spectrum (EM)
Electromagnetic Spectrum – all the wavelengths of the electromagnetic radiation
Visible light is just a small part of the EM spectrum
Red has the LONGEST wavelength = low frequency
Violet had the SHORTEST wavelength = high frequency

6. Telescopes
Telescopes – Instruments used to collect EM from the sky, concentrating it for better observation
Reflecting can be made VERY LARGE & attract more light w/out distorting the image; it is easier to make large mirrors than large lenses!
2 basic types:
Refracting – bends light with a lens, focused by an eye piece
Reflecting – Light is reflected by a curved mirror onto another curved mirror and that mirror reflects to an eye piece

7. The Past, The Present, The Future…
Edwin Hubble – discovered that the universe had other galaxies, & that it is expanding.
NASA developed four space telescopes, the Great Observatories Series, in a sequence to study all types of light
James Webb is the newest telescope, now being assembled.
Additionally, there are telescopes that collect invisible radiation (radio, infrared, x, gamma). But, the earth’s atmosphere shields us from most of these waves so the only way to study many forms of radiation is from space.
Spacecraft : include unmanned space probes, entry vehicles and landing craft.
e.g. Pioneer, Voyager, Galileo, Cassini, Spirit, Opportunity, Curiosity
Each mission or program costs hundreds of millions of dollars.
Human space exploration:
Humans have reached no farther than the moon (July 1969)
Neil Armstrong first foot on the moon… NASA plans to send astronauts back to the moon before venturing to Mars.