SCIENCE 9 UNIT E

Technologies that Advance our Understanding of Space

1.2 Discovery Through Technology

The astronomers Tools

Humans have invented many tools throughout history to study the sky

Sundials chart the passage of time with the sun

Astrolabes are used to chart star position

Why would we want these?

The Telescope

The telescope first allowed man to see the planets closest to the Earth

It showed space was much larger than it was imagined

Today we have super-powerful optical and radio telescopes on Earth, satellites orbiting Earth and space-based telescopes which continue to expand our understanding

http://www.youtube.com/watch?v=t5ceKXK6Kdk

http://devour.com/video/flying-over-earth/

Galileo Galilei, in the 1600’s saw things like the moons on Jupiter and sunspots using the first telescope

Johannes Kepler did research on the movement of planets and discovered that planets moved in orbits in the shape of ellipses.

The Immensity of Density and Time in Space

Finding an appropriate measurement is important in describing distances

What unit would you use to measure the length of the school?

The distance around Lac la Biche?

2 New Units Of Measurement

1) Astronomical Unit (AU)- used to measure distance within our solar system It is the distance from the center of the

Earth to the center of the sun

1AU= 149 599 000 km

2) Light-years- a light year is usually used to measure the distance of things outside of our solar system like stars, nebulas and galaxies It is the distance light travels in one year Light travels at 300 000 km/s A string 1 light year (ly) long would wrap

around Earth’s equator 236 million times

1 ly= 9.5 trillion km www.youtube.com/watch?v=j2uWp8WpGwY

https://www.youtube.com/watch?v=Op3AYaJc0Xw Distances in Space

https://www.youtube.com/watch?v=_Lsj-Hz-NS4

Think about it!

Since it takes light a long time to reach us from the stars, we are seeing light that left the star along time ago

The further we look into space the further into the past we look

Why is this?

3.1 – Using Technology to See the Visible

There are two types of optical telescopes that are used to study the stars

Refracting telescopes use two lenses to focus starlight

However, refracting lenses are limited in size – if they are too large, they bend under their own weight

Reflecting telescopes use a large curved mirror

Refracting Telescope Demo

The curved mirrors are not limited in size (the largest one has a diameter of 6 m)

Some newer telescopes use segmented mirrors which can improve resolving power by changing the shape of the mirror

One technique used to improve resolution using telescopes is to use interferometry

Reflecting Telescope Demo

In interferometry, two telescopes are linked and their images are combined, forming one image

Ground-based telescopes are limited, however, by the clarity of the atmosphere

Space-based telescopes, like the Hubble Space Telescope, do not have the disadvantage of atmospheric interference

The Hubble Telescope

http://hubblesite.org/the_telescope/ The Hubble Space Telescope’s launch was

in 1990 Every 97 minutes, Hubble completes a spin

around Earth, moving at the speed of about 8 km per second— fast enough to travel across the Canada in about 11 minutes. As it travels, Hubble's mirror captures light and directs it into its several science instruments to create images of earth

3.2 – Using Technology to see Beyond the Visible

Stars not only produce visible light, but they also produce other radiation

Radio telescopes are used to study stars These telescopes have an advantage

over optical telescopes – they can operate day or night, regardless of weather

However, they must be placed far away from any sources of radio waves

Radio telescopes are essentially like large satellite dishes

Not only can they be used to study the stars, but they can also tell us about the distribution of other matter in space (which cannot be determined by optical telescopes)

Just like optical telescopes, radio telescopes can also use interferometry

For instance, the VLA (Very Large Array) in New Mexico uses 27 large radio telescopes arranged in a Y-shape

As a result, the resolving capacity of the VLA would be the same as a single telescope with a dish 27 km in diameter

Space Probes We have sent a number of probes to study the

planets These probes are much cheaper and safer

than sending manned missions To date, none of the probes have left the solar

system A Recent Probe in the news was sent 12 years

ago to study a comet. This was called the Rosetta Mission

3.3 – Using Technology to Interpret Space

We cannot tell how far a star is away just by staring at it through a telescope

We can determine distance through a method known as triangulation:

triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline.

Triangulation Example

1. Measure a baseline, with each end clearly marked

2. Use a protractor to determine the angle from one end of the baseline to the object

3. Determine the angle at the opposite end of the baseline

4. Create a scale drawing (as shown here)

5. Measure the perpendicular between the baseline and the object

6. Use the scale to determine the distance

Parallax

Parallax is the apparent shift in position of a nearby object when viewed from two different placesAstronomers use this shift in position in their triangulation calculations when measuring the distance to a starThe length of the baseline is the diameter of Earth’s orbit around the Sunhttps://www.youtube.com/watch?v=_

Lsj-Hz-NS4

Star Composition

When light from a star is passed through a prism, it creates a rainbow-like pattern

However, the patterns from stars often have black “gaps” in them

These gaps are due to gases absorbing specific wavelengths of light

These gaps can then be compared to known gases and will identify the star’s composition

As you can see here, the individual lines correspond to various elements

We use a spectrometer to analyze the star’s composition

Spectral Analysis Demo

Think about it!

How can we analyze a star’s composition?

Star Movement

We can also use the spectra of stars to determine their movement relative to the Earth

The Doppler Effect indicates that if an object moves towards an observer, the frequency of waves emitted from it increases

As well, if the object moves away from the observer, the frequencies decrease

In stars, this is known as “red shift” (the star is moving away) or “blue shift” (the star is moving towards us)

The amount of red shift or blue shift indicates the speed of the star

Measuring Star Movement Demo

2.3 – Using Space Technology to Meet Human Needs on Earth

We can use space technologies here on Earth

One of the main ways that we use this technology is through Satellites

Communication Satellites

In the early 20th century, telegraph and telephone messages traveled through wires

Today we use digital signals from satellites that allow clearer transmissions and a larger number of users – examples would be TV signals and cell phone signals

Observation and Research Satellites

Geosynchronous satellites (those that maintain a constant position) are used to monitor weather

Other satellites, such as LANDSAT and RADARSAT can track ships at sea, forest fires, environmental damage, and natural resources

Remote Sensing

The main purpose of satellites in low Earth orbit (200 to 1000 km altitude) is to make observations about the Earth

This provides information about the condition of the environment, natural resources, and the effects of urbanization

The Global Positioning System

There are 24 GPS satellites that orbit the Earth

At any one point, there are at least three of these satellites that are above a given location at any moment

They produce radio signals that are picked up by receivers

These radio signals contain time information

The time information from each satellite is compared with the internal clock on the receiver, and the time difference between the signals indicates the distance from the satellite

When three signals overlap, they will provide the user with their position

The GPS was originally developed for the US military

In 2000, non-military users could finally receive a full-quality signal (prior to this, civilians could only receive a less accurate signal)

Practice Your Skills

Complete the Skills Practice with GPS Use

Space Age Materials and Systems

Many different materials and systems originally designed for space have been put to use on Earth

Almost all sectors of business have been advanced through the use of these materials and technologies:

Computer Technology

Computers have been used to analyze the structure of spacecraft, the monitoring of onboard systems, and the training of astronauts

On Earth we use the same technologies in offices, to analyze buildings and bridges, and to develop virtual reality software

Consumer Technology Astronauts use

specialized foods in space, and much work has been put into the studies of insulation and aerodynamics

We now can buy many enriched freeze-dried foods

New, more efficient designs of bike helmets, golf balls, running shoes and ski goggles are the results of the work done to improve spaceflight

Medical and Health Technology

Motion sickness is a problem in space, so medications were developed to counteract it

As well, digital imaging that was developed for satellites is now used in medicine to detect cancers

Industrial Technology

Lasers are used for communication in space, and they are now used for communication and manufacturing here on Earth as well

Transportation Technology

Special materials that were used in parachutes and spacecraft are now used in automobile designs, even down to the tires!

Public Safety Technology

A large amount of our exploration in space is done by robots because it is too dangerous for humans

Robots with similar designs are now used for similar tasks on Earth (such as the disposal of explosives)

As well, space debris can fall to Earth In 1978, a Soviet satellite crashed into

the Great Slave Lake area in NWT During re-entry, the disintegrating

satellite showered radioactive debris from its power plant over a 124 000 km2 area

The clean-up carried out by the Canadian and US military cost about $15 million

End of Section

Assignment: Section Review p. 455 # 1 – 9