Topic 4 Space Exploration Bigger and Smarter Telescopes Topic 4 Space Exploration

New Discoveries Sir William Herschel: In 1773 Sir William Herschel (an English astronomer) built one of the first really large reflecting telescopes and used it to discover Uranus His discovery of Uranus was exciting because it proved the existence of other planets in the solar system

New Discoveries Gerard Kuiper: Discovered methane gas in Saturn’s moon (the moon Titan) and two new moons of Uranus He made these discoveries with the world’s largest refracting telescope (101 cm) in the world (at that time) which was found at the Yerkes observatory near Chicago.

Combining Telescopes Now our telescopes are so advanced that computer programs can combine images from two or more telescopes to create very detailed images of very distant objects.

Combining Telescopes The twin Keck telescope has a resolving power that can allow it to distinguish each headlight on a car from 800 km away!

Combining Telescopes Spitzer Space Telescope: The Musical

Adaptive Optics Adaptive Optics: Technology that adjusts the mirror of a telescope, or adjusts the image of a telescope., to cancel the effects of the constant changes in Earth’s atmosphere

Adaptive Optics Stars twinkle because the motion of Earth’s atmosphere refracts their light randomly and this makes it difficult for astronomers to get a clear view New Technology Telescope in La Silla, Chile

Adaptive Optics In order to solve this problem computers are put into giant reflecting telescopes under the mirrors The computer makes small changes to the mirrors in order to account for the moving atmosphere and allows for much more detailed images of celestial objects

Adaptive Optics Progress in Telescopic Astronomy Keck Telescope

Distance to the Stars Many astronomers (and regular people) often ask questions such as: Where are stars? How far away are these stars from Earth? How big is the universe?

Measuring With Triangulation Triangulation / Parallax Technique: A method of measuring distance indirectly by creating an imaginary triangle between an observer and an object whose distance is to be estimated.

Steps of Triangulating Create a Baseline: The distance between two observers is measured Object of Interest Measure Distance A Baseline B Observers

Steps of Triangulating Measure the angles from the end of the Baseline: Both observers will look at the object of interest and find the angle between the object and the baseline A B Measure Angles

Steps of Triangulating Make a scale drawing of the imaginary triangle. A triangle is drawn to scale and the distance to the object is discovered through trigonometry Scale Example: 1 km = 1 cm A B Measure the Various Distances to the Object

Triangulating on a Star Find the longest baseline possible: The longest baseline on Earth is its diameter In order to use this baseline, a star is viewed twice over a six month period This gives a baseline that is the Earth’s diameter

Triangulating on a Star Use Parallax to find reference points: As the Earth moves around the sun the star will appear to move against the background of other stars

Triangulating on a Star Measure the angles of the imaginary triangle: Parallax allows the observer to measure the angles of the triangle

Triangulating on a Star Discover the distance to the star: The angles of the triangle allow for the discovery of the distance of the star from Earth.

Large Enough Units: AU and Light-Years The nearest star to Earth is Proxima Centauri and it lies more than 272000 Astronomical Units (AU) from the Sun Astronomical Units (AU): The distance from Earth to the Sun 1 AU = 150000000 km

Large Enough Units: AU and Light-Years Astronomical Units are good to use when looking at the solar system, however since the Universe is so large, Astronomical Units become impractical Instead, Astronomers use Light-Years to measure distances in the Universe

Large Enough Units: AU and Light-Years The distance that light travels in one year 1 Light-Year = 63240 AU = 9.5 trillion km (ie. 95000000000 km!!!!!)

Large Enough Units: AU and Light-Years ***Note: Proxima Centauri is 4.28 Light-Years / 272000 AU / 40,800,000,000,000 km away from Earth