Current Event Due Friday! Complex Knowledge: demonstrations of learning that go aboveand above and beyond what was explicitly taught. Knowledge: meeting the learning goals and expectations. Foundational knowledge: simpler procedures, isolated details, vocabulary. Limited knowledge: know very little details but working toward a higher level. Understand how our view of the solar system has changed over time and how discoveries made have led to our changing our view of the solar system. Learn planetary characteristics such as number of moons, size, composition, type of atmosphere, gravity, temperature and surface features. Understand the movement of planetary bodies. Understand which planetary characteristics are more important than others when it relates to our understanding of other worlds. Understand how proximity to the sun influences planets. Understand the methods and tools scientists use to learn about other planets and moons in our solar system. Understand the conditions needed for a habitable world and determine if there are habitable worlds in our solar system or outside the solar system. Understand how we look for and study solar systems other than our own. EdPuzzle Due Tonight! Current Event Due Friday!

Read Now!: Extrasolar Planets

Extrasolar Planets -> exoplanets One of my personal top 3 favorite topics in Astronomy!  Extrasolar Planets -> exoplanets

How do astronomers use data to detect exoplanets? Today’s questions: How do astronomers use data to detect exoplanets? Why are exoplanets so hard to observe directly?

A Strange New Planet… http://florida.pbslearningmedia.org/resource/ess05.sci.ess.eiu.otherplanets/a-strange-new-planet/

What is an extrasolar planet? Extrasolar planets or “exoplanets” are planets outside our solar system. As of today, there are 1,932 3,439 3,584 3869 exoplanets on record with the International Astronomical Union. the first exoplanet around a star like our sun was found in 1995. Until recently, most exoplanets found were planets similar to or bigger than Jupiter. 51 Pegasi b With recent observational data and improvements to our technique, it is estimated that the milky way alone may have tens of trillions of exoplanets.

1. Direct Imaging: Astronomers can take pictures of exoplanets by removing the overwhelming glare of the stars they orbit 5 Ways to Find a Planet Taking Pictures http://planetquest.jpl.nasa.gov/system/intera ctable/11/index.html

This is Fomalhaut, approximately 100 AU from its star (pluto is only 40 AU)

Future direct-imaging instruments might be able to take photos of exoplanets that would allow us to identify atmospheric patterns, oceans, and landmasses. (Aliens anybody???)

Pro Con it has the potential to be pretty freaking awesome! you need absolutely perfect conditions for it to happen You still can’t get very good resolution It’s really hard (Record one of the above cons)

Why can’t we see all planets directly? Don’t give off their own light. Way too small Lost in the glare of their stars.. http://kepler.nasa.gov/images/videos/LostInG lareWEB1_H264.mov

2. Gravitational Microlensing: Light from a distant star is bent and focused by gravity as a planet passes between the star and Earth 5 Ways to Find a Planet Light in a Gravity Lens http://planetquest.jpl.nasa.gov/system/intera ctable/11/index.html

Pros: Cons: You can detect exoplanets! Sometimes, free-floating planets in space, ones that don't orbit a star, will cause quick microlensing events that astronomers will record. These events give us an idea of how common these so-called 'rogue' planets are in the galaxy Cons: You can’t predict where they will happen, so they have to watch large parts of the sky over long periods of time

3. Astrometry: The orbit of a planet can cause a star to wobble around in space in relation to nearby stars in the sky 5 Ways to Find a Planet Miniscule Movements http://planetquest.jpl.nasa.gov/system/interact able/11/index.html

Astronomeristery…er…Astronometery Con Pro Extremely hard to do Doesn’t work well with Earth based telescopes because of our atmosphere We find very few exoplanets this way Requires precise, expensive optics (Pick one con to write down) Exoplanet!

Stop! What is the Doppler effect?

Doppler Effect Sound Light

4. Radial Velocity Technique These slight movements affect the star's spectrum. If the star is moving towards the observer, it’s light waves would be smooshed together; it would appear shifted towards blue. If it is moving away, it’s light waves would be spread out; it will be shifted towards red. The radial velocity method relies on the fact that a star does not remain completely stationary when it is orbited by a planet.

http://planetquest.jpl.nasa.gov/system/intera ctable/11/index.html Orbiting planets cause stars to wobble in space, changing the color of the light astronomers observe http://planetquest.jpl.nasa.gov/system/intera ctable/11/index.html 5 Ways to Find a Planet Watching for Wobble

4. Radial Velocity Technique If the shifts are regular, repeating themselves at fixed intervals of days, months, or even years, it means that the star is moving ever so slightly back and forth. This, in turn, is almost certainly caused by a body orbiting the star, or if it is of a low enough mass it is called a planet.

Pro It's hard to argue with success. Radial velocity was the first successful method for the detection of exoplanets, and is responsible for identifying hundreds of faraway worlds. It can also be achieved by ground based telescopes! Huzzah! Con It is a fundamental feature of the radial velocity method that it cannot accurately determine the mass of a distant planet, but only provide an estimate of its minimum mass. This is a serious problem for planet-hunters, because mass is the leading criterion for distinguishing between planets and small stars. Some astronomers believe that at least some of the "planets" detected by spectroscopy are not planets at all but very low-mass stars.

Head to Canvas Work on activity posted there. Due at 11:59 Tomorrow Night!!!