Exploring Space: The Universe Exploring Space: The Universe

Astronomy (AKA astrophysics): the study of matter outside the Earth's atmosphere and its physical and chemical properties

Universe : all of space and everything in it Most (90%) of the universe is made up of: dark matter: stuff we think is there due to amount of mass we think is there but is not detected by the instruments we have available at this time

Nebula : large amount of gases spread out in an immense volume all stars start as part of a nebula

Star : large amount of glowing gas in a small volume mostly hydrogen creates energy through nuclear fusion in its core Globular cluster : a group of 10,000 to 1 million stars (that’s a LOT)

Galaxy : a giant structure that contains hundreds of BILLIONS of stars 3 main types: 1. spiral 2. elliptical 3.irregular

1.spiral : have arms that spiral outward like a pinwheel Milky Way : our galaxy We are on an outer “arm”.

Artist’s rendition. Not a real photograph!!

2. elliptical : looks like a flattened ball; 3.irregular : no regular shape Galactic cluster : groups of galaxies held together by gravity

Supernova : explosion of dying large stars Neutron star : extremely small, dense leftovers from a supernova supernovae shrink into neutron stars

Black hole : what remains after the most massive stars die gravity is so strong that nothing can escape (not even light)gravity is so strong that nothing can escape (not even light) many scientists think the center of Milky Way contains a black holemany scientists think the center of Milky Way contains a black hole Artist’s rendition. Not a real photograph!!

Distances in space How far away is stuff in space? How do we figure it out? The answer depends on what we’re trying to measure.

Within our solar system we use radar and the formula for speed: Speed = distance/time Speed of light = 186,000 mi./sec. (300,000 kps) (that’s traveling around the earth about 7 ½ times in ONE SECOND!) X-rays, microwaves, radio waves all travel at the speed of light.

Astronomical Unit (AU): distance between the Earth and Sun Approximately 93,000,000 miles Used only within our solar system to measure distances between planets and the sun

Astronomical Unit (AU) chart

Light-year : distance light travels in one year Speed of light = 186,000 mi./sec. 1 Light-year = 5.9 trillion miles (5,900,000,000,000 miles) Takes about 8 minutes for sunlight to reach Earth Takes about 4 years for starlight from next nearest star to reach EarthTakes about 4 years for starlight from next nearest star to reach Earth That star is 4 light-years away!

Parallax : the apparent change in position of an object when you look at it from different places used to measure distance to nearby stars smaller shift = greater distance.

Electromagnetic Energy : energy that travels through space in the form of waves This energy is a type of radiant (light) energy.

Two properties of waves: 1.Wavelength – distance between one crest of a wave to the next crest 2.Frequency – number of wavelengths that pass a point in a given amount of time.

wavelength

Long wavelength = low frequency = low energy Short wavelength = high frequency = high energy

Electromagnetic Spectrum: range of different types of electromagnetic energy Each EM energy has a different wavelength/energy level.

Radio waves : think lazing at the beach, stretched out, listening to some tunes; summer in slow motion Microwave rays : sheesh, we’re lazy. nobody cooks a regular meal anymore. Infrared rays : heat seeking; you need to move slowly and be quiet to hunt TV remote uses this too (because we’re too lazy to get up and change the channel) Visible light : what humans can see (in the middle) EMS diagram

Visible light: visible colors of red, orange, yellow, green, blue, indigo, violet (ROY G BIV) longest wavelength = red shortest wavelength = violet

Radio waves : think lazing around at the beach, stretched out, listening to some tunes; summer in slow motion Microwave rays : sheesh, we’re lazy. nobody cooks a regular meal anymore. Infrared rays : heat seeking; you need to slow down and be quiet to hunt TV remote uses this too (because we’re too lazy to get up and change the channel) Visible light : what humans can see (in the middle) UV rays UV rays : bees can see ‘em (but you can’t); (violet is like blue - on that side of visible light) X-rays : it’s pretty exciting when you break something (but not in a good way) Gamma rays : very excited, lots of energy (Yo Gabba Gabba)

Doppler effect the apparent change in the frequency of a wave caused by the relative motion between the source of the wave and the observer

Doppler effect

Red shift: describes the change in wavelength as objects move farther away wavelengths get longer and shift into the infrared end of the EMS shows the universe is expanding

How we get information about space: ( no man has ever been farther than the moon ) One way: telescopes!

Telescopes collect and focus different types of electromagnetic radiation not all light can get through Earth's atmosphere, so for some wavelengths we use telescopes aboard orbiting satellites A sample of telescopes (as of Feb. 2013) operating at wavelengths across the EMS.

Optical telescope: uses a curved lens and/or mirrors to collect a large amount of visible light and focus it into a small area Isaac Newton's telescope

Radio telescope: collect radio waves from space to create computer generated images

These things are BIG! See the man?

UV telescope: Space based (little UV gets to the ground) Looks at youngest & hottest stars GALEX observatory

X-ray telescope: Chandra X-ray observatory Space based (X-rays are absorbed by Earth’s atmosphere) Looks at solar flares (& black holes, too!)

the Hubble Space Telescope Hubble Space TelescopeHubble Space Telescope Looks at distant galaxies & at planets within our solar system Kepler Space Telescope Looks for planets around other stars (exoplanets)

Fin That means “end”. You is done. And so am I. Like for realz.