Science 9 Aim: Introduction to Space

Agenda Unit Test Lunch Introduction to Space Notes

Unit E: SPACE EXPLORATION

Human understanding of both Earth and space has changed over time.

Technological developments are making space exploration possible and offer benefits on Earth. Optical telescopes, radio telescopes, and other technologies advance our understanding of space. Nordic Optical Telescope in the Canary Islands

Early Views of the Cosmos The movements of celestial bodies have been observed for thousands of years Ancient cultures explained their observations of bodies in space with myths and legends

Early Views of the Cosmos The First Nations peoples of the Pacific Northwest thought the night sky was a pattern on a great blanket overhead

Early Views of the Cosmos Many Ancient Civilizations Celebrated Annual Cosmological Events…  Winter and Summer Solstices  Spring and Fall Equinoxes

Early Views of the Cosmos Solstice Either of the two times in the year when the Sun reaches its highest or lowest point in the sky at noon In the northern hemisphere, the summer solstice occurs near June 21 (longest day of the year) and the winter solstice occurs near December 21 (shortest day)

Early Views of the Cosmos Solstice These events were very important to early cultures, as they indicated the coming summer or winter 3500 years ago, ancient people built Stonehenge that help mark the solstices

Early Views of the Cosmos Equinox from the Latin for “equal night” either of the two times a year when the Sun crosses the equator day and night are of equal length usually on or around March 21 (“vernal equinox”) and September 23 (“autumnal equinox”) Equator

Models of Planetary Motion Geocentric  Heliocentric

Models of Planetary Motion Geocentric (Earth-Centred) model of the universe that places Earth at the centre with the Sun, Moon, and planets revolving around it proposed by the Greek philosopher Aristotle about 2000 years ago could not explain the retrograde (backward) motionof Mars, Jupiter, and Saturn

Models of Planetary Motion Heliocentric (Sun-Centred) Model of the universe that places the Sun at the centre with the Earth and planets revolving around it Proposed by Polish astronomer Nicholas Copernicus in 1530 Could not accurately predict planetary motion

Models of Planetary Motion Heliocentric (Sun-Centred) About 100 years after Copernicus, the scientists, such as Galileo Galilei used the new technology of the telescope to provide solid evidence for this theory

Models of Planetary Motion Shape of Planets’ Orbit In the early 1600’s Johannes Kepler, suggested that planetary motion would be easier to predict if orbits were elliptical rather than circular. Kepler’s Model:

Discovery Through Technology Technology used to study space has evolved throughout history. With each technological advance came better explanations for what was observed.

Discovery Through Technology Ancient Egyptians invented a device called a “Merkhet” to chart astronomical positions and predict star movement

Discovery Through Technology Egyptians also invented a device known as the Quadrant around the 2nd century AD. It was used to measure a stars height above the horizon.

Discovery Through Technology Arabian astronomers used the “Astrolabe” to make accurate charts of star positions

Discovery Through Technology In the 14th Century, astronomer Levi ben Gurson invented the cross-staff. Used to measure the angle between the moon and any given star.

Measurement in Space The astronomical unit (AU) is a measure of distance used to describe the position of planets relative to the Sun. 1 AU is equal to the average distance from the centre of the Earth to the centre of the Sun—about 149, 599, 000 kilometres! Why is this number an average number? Proxima Centauri, the closest star to our Sun, is 4.3 light-years away. Light travels at 300 000 km/s. Calculate how far away Proxima Centauri is in kilometres.

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Measurement in Space Light travels at about 300,000 km/s A light-year is the distance that light travels in 1 year (about 9.5 trillion kilometres). It is used to measure distances between stars and galaxies. The nearest star to Earth after the Sun, Proxima Centauri, is around 4.3 light-years away How many kilometres is that? Proxima Centauri, the closest star to our Sun, is 4.3 light-years away. Light travels at 300 000 km/s. Calculate how far away Proxima Centauri is in kilometres.

Using Light Years Measure Distance... and Time Because some stars are so far away and we know that their light takes time to get here. Orion nebula – 1350 ly Alpha Centauri – 4.37 ly

Time Because light years are measured in human years they tell us how long the light took to get to Earth. Depending on the objects distance, you are seeing the light from the object as it was that many years ago. Orion nebula – 1350 ly = 1350 years ago Alpha Centauri – 4.37 ly = 4 years 3 months ago

Homework for the weekend Read 371-405 P 376 # 1-7 P 383 # 1-7 P 391 # 1-4, 6-8 P 400 # 1-9 P 405 #1-7 Due Tuesday Dec 17. Email them to me if you are not here next week.