2 Section 1 – Radiation from space What is the electromagnetic spectrum?What is the difference between refracting and reflecting telescopes?What is the different between optical and radio telescopes?Section 1 – Radiation from space
3 Electromagnetic waves Light from the PastWhen we see a star, the light left that start many years ago. Sometimes it takes millions of years for that light to reach our eyes on EarthThis is a form of radiation (studied in heat transfer), which transmits energy from one place to another by electromagnetic waves.Electromagnetic RadiationElectromagnetic radiation is everywhere around you – turning on the radio, peering into a microscope or having an X-RayExamples:Sound Waves (but they can’t travel through space so they are converted to Radio Waves)Ultraviolet WavesGamma Rays
4 Electromagnetic Waves All of these forms of electromagnetic radiation come together to form the electromagnetic spectrum.Different forms have different frequencies, or the number of wave crests that pass a given point per unit of time.The shorter the wavelength, the higher the frequency.All waves travel at the speed of light, or at 300,000 km/s.Still, it can take millions of years for these waves to reach Earth.
6 Optical telescopesOptical telescopes use light (a form of electromagnet radiation) to produce magnified images of objectsHow else would we know there are craters on the moon?What could you use a telescope to see?Light is collected by a lens or mirror, then forms an image at the focal point of the telescope, then by looking through the eyepiece, it magnifies the image so you can see if clearly.There are two types:Refracting telescopesReflecting telescopes
7 Optical telescopes Refracting Telescopes Uses convex lenses, which are curved like the outer surface of a ballLight from the object passes through a convex lens and is bent to form an image at the focal point
8 Optical telescopes Reflecting Telescopes Uses a curved mirror to direct lightLight strikes a concave mirror (bent inward instead of outward) and then the light is reflected into the eyepiece
9 Optical telescopesYou can use an optical telescope (you can buy one at many outdoor stores) but professional telescopes are located in observatories, or a dome shaped building used by astronomers and houses telescopes.Not all telescopes are inside a building or even on Earth – the Hubble Space Telescope was launched in 1990 by the space shuttle Discovery.When it was first launched, astronomers expected to see even more clear pictures, since the telescope was launched into space, but a mistake was made when the largest mirror of this refracting telescope was built.In December 1993, a team of astronauts set out on a mission to install new, correct mirrors on the HubbleNASA controls the Hubble with radio commands and images are sent back to ground with radio signals.
13 New advancesSince first developed in the 1600s by Gailieo Galilei, telescopes have constantly been improved to better serve research needs.Mirrors are being made larger and larger to reflect more lightActive Optics – a computer corrects for changes in temperature, mirror distortions and bad viewing conditionsAdaptive Optics – uses a laser to probe the atmosphere to take into account all of the possible conditionsCurrently, the plans for the world’s largest optical telescope will be housed in an observatory on the Mauna Kea dormant volcano in Hawaii. Construction has yet to begin but is estimated to be operational in 2018.The world’s smallest telescope is an experimental telescope to help restore vision (currently still in testing and not FDA approved)
15 Radio telescopesUnlike the optical telescopes, which require light to be able to view objects in space, radio telescopes use a different method.A radio telescope collects and records radio waves traveling through space.It can be used during the day, night and most weather conditions
16 Review – Section 1How long does it take light to travel through space?What does the electromagnet spectrum consist of?What is an advantage of a radio telescope over an optical telescope? A disadvantage?How could adaptive optics help optical telescopes?Page 635 – Define the following terms:RocketSatelliteOrbitSpace probe
17 Section 2 What are natural and artificial satellites? What are the differences between artificial satellites and space probes?What is the history behind the race to the moon?Section 2
18 RocketsSpecial engines that carry their own fuel and work in space, or rockets, are responsible for the blast off into spaceTo break free of gravity, spacecraft must travel at a speed greater than 11 km/s (same as 24, mph!!!!)Why do rockets need their own fuel?Rockets do not require air to burn their fuel – space has no air for it to use!An example of a simple rocket would have a burning chamber and a nozzleThere are two types of rockets that are categorized by the type of fuel they use
19 Rockets Liquid fuel Can but shut down and restarted after ignited Liquid PropellantSolid PropellantLiquid fuelCan but shut down and restarted after ignitedPreferred for long-term space missionsScientists on Earth can send start and stop signals to the spacecraft’s engines whenever they need toSolid, rubberlike fuelMore simpleCannot be shut down after they are ignitedCan be used in combination with liquid fueled rockets for launching
21 satellitesSputnik I was launched in 1957 by Russia and was the first artificial satelliteAny object that revolves around another objectIn space, there is no gravity, but the gravitational pull from Earth is what holds satellites in place in their orbit, a curved path around Earth.Sputnik I orbited for 57 days before being pulled back into Earth’s orbit and burning up.
22 Why use satellites?Artificial satellites are used to communicate data back to EarthCommunication Satellites allow use to watch TV and talk on our phonesWeather Satellites monitor current conditions all over the globeScientific satellites help gather information for NASA and other scientific organizationsNavigational satellites help planes and ship know where to goMilitary satellites give top secret information
23 Space probesAn instrument that gathers information and send it back to EarthUnlike satellites, which only stay in Earth’s orbit – probes travel into the solar systemExample: Pioneer 10Launched in 1972Sent back photos of Jupiter as the first probe to encounter an outer planetTransmitter failed in 2003 but it continues on through space
24 Space probesVoyager I and Voyager II were launched in 1977 and are now headed toward deep spaceVoyager I flew past Jupiter and SaturnVoyager II flew past Jupiter, Saturn, Uranus and NeptuneThese probes continue to explore the solar system and transmit data and are expected to do so for at least 20 more years
26 galileo Launched in 1989 Reached Jupiter in 1995 Released a smaller probe to travel to the surface of JupiterBefore it was crushed in the atmosphere, it transmitted information about Jupiter’stemperatureCompositionatmospheric pressuresrings, moons, and magnetic fields
27 galileoJupiter’s moon Europa shows the possibility of an ocean under the icy surfaceThe study of Europa ended in – more advanced probes are needed to study EuropaOctober/November 1999, the probe approached Io, which contains a volcanic vent named Loki, which emits more energy than all of Earth’s volcanoes COMBINED
28 Three stages led the United States to reach a goal for all man kind Race to the moon
29 Phase i: Project mercury Russia launched Sputnik I in 19571961 – Russia sends Yuri A. Gagarin into space and returned home safely. After this, President Kennedy called for the US to someone to the moon and return them safely to Earth and make it happen by 1960This launched Project Mercury – whose goal was to orbit a piloted spacecraft around Earth and bring it back safelyMay 5, 1961 – Alan B. Shepard became the first US citizen in space1962 – Mercury astronaut John Glenn became the first US citizen to orbit Earth
30 Phase II: Project gemini Goals:Have two spacecraft meet in space and connectThe Gemini spacecraft was launched by a liquid fueled rocket known as Titan IIStudy the effects on space on the human bodySend space probes to the MoonRanger was the first sent to the MoonSurveyor landed on the Moon in 1699Lunar Orbiter took photos of the Moon’s surface to determine the best landing spot
31 Phase III: Project apollo Goal: reach the Moon’s surfaceJuly 20, 1969 – Apollo 11 lands on the Moon’s surfaceNeil Armstrong was the first human to set foot on the Moon“That’s one small step for man, one giant leap for mankind”Three astronauts explored its surface for two hours while others remained inside the Command ModuleTotal of six lunar landings brought back more than samples of moon rock and soil