Ch. 26.1 Viewing the UniverseMARQUES NOTES – EARTH SPACE SCIENCE

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!

So… How was this picture taken?

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. 9.46 TRILLION kilometers* Closest star to earth (besides the Sun) is Proxima Centauri (~ 4.2 light years away)

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

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

• 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.

The Past, The Present, The Future…