Astronomy Merit Badge

1. Astronomy Merit Badge God is infinite, so His universe must be too. Thus is the excellence of God magnified and the greatness of His kingdom made manifest; He is glorified not in one, but in countless suns; not in a single earth, a single world, but in a thousand thousand, I say in an infinity of worlds. - Giordana Bruno, 1584, "On the Infinite Universe and Worlds"

2. The word Astronomy means “naming the heavens”

3. Why should we care about Astronomy? Astronomy Merit Badge

4. Why should we care about Astronomy? Objects in the sky seem remote but there are many reasons we should pay attention to them

5. Why should we care about astronomy ? Timekeeping In the past: • Before watches and written calendars people could tell the time of day and the date from the sky. This was particularly important for farmers in determining when to plant their crops, to know when the spring rains were coming or when winter would soon be setting in. • Stonehenge, pyramids, etc. all have architectural elements that were used for timekeeping • There were pocket sundials made in 1600s which would allow you to tell the time, even at night, using the stars, within 15 minutes of accuracy. Modern day: If you know your constellations and you know the time of year, you can determine the approximate time by looking at the night sky.

6. Why should we care about astronomy ? Navigation In the past: Before compasses and GPS, travelers used the stars to tell direction, especially sailors (using a sextant). Modern day: Compasses break, GPS batteries lose power, GPS units can’t find satellites, or are simply inaccurate. Stars are always there and with stars and a map you can find your way even in the dark

7. Why should we care about astronomy ? Predicting the future In the past: The earliest astronomers (Sumerians, Egyptians, Chinese) watched the skies for scientific reasons but also to try and predict events on earth (birth and death of kings, outcomes of battles, etc.). The only known record of this actually working was the Star of Bethlehem. The three wise men were amateur astronomers. Astrology is bunk. The only effect the heavens have on our daily lives is providing light and heat and the occasional news story about a close brush with a space object. Modern day: Modern astronomers survey the sky for local threats to the Earth such as asteroids and comets with orbits close to us (NEOs – Near Earth Objects), dangerous solar activity (flares), and local supernovae (a star blowing up close to us (within 100 light years) could cause us a lot of trouble)

8. Why should we care about astronomy ? • Scientific advancement • In the past: Studying the stars helped people learn to practice agriculture, predict seasonal floods, understand the shape of the Earth. • Modern day: • Understanding the chemical and physical processes in the stars and other celestial objects can help us understand how things work on Earth. • Mapping the universe can help us understand what it looks like and appreciate God’s engineering skill.

9. Why should we care about astronomy ? There are extremely cool things out there to look at and study • Manmade: Satellites, ISS • Meteorites and fireballs (these last 4-5 seconds) • Aurorae (if conditions are right) • Details of lunar craters • Other planets • Moons of other planets • Asteroids and comets • Asteroids with moons (Eris, etc. – get from Celestia presentation) • Differently colored stars (you can actually see the colors) • Double stars • Nebulae (Ring nebula, Orion nebula) • Globular clusters • Galaxies by themselves and galaxies that are in the process of colliding with each other • Exploding stars (supernovae – 1987A) • Black holes, white holes, wormholes • Extrasolar planets (with professional equipment) • Views of galactic clusters taken by Hubble telescope in areas of space thought to be blank! • See back in time to the beginnings of the universe (speed of light) • Maybe alien life forms???? • And lots more!!

10. Observing Safety Astronomy Merit Badge

11. Observing Safety – Weather Safety • Weather Safety – exercise the same weather precautions as on a campout or hike. • When observing, you will be outdoors for long periods of time without moving very much. You can get frostbite just as easily in your backyard as you can on the Arctic tundra. You can get heat exhaustion even at night if it’s hot enough outside. Dress appropriately and take the appropriate precautions for cold or hot weather. • Heat Exhaustion • Signs – elevated body temp, skin pale and clammy, heavy sweating, nausea, dizziness, fainting, pronounced weakness and tiredness, headache, muscle cramps. • Treatment – have victim lie down in a cool spot with feet raised. Apply cool damp cloths to skin. Give them water • Heatstroke • Signs – red, hot dry skin, no sweating, extremely rapid pulse, confusion or disorientation, fainting or unconsciousness, convulsions • Treatment – place victim in a cool spot with head and shoulders raised, remove outer clothing, sponge bare skin with cool water, apply cold packs, use fan or place victim in tub of cool water. Obtain medical help immediately. • Hypothermia – when body’s core temperature drops so low it can no longer keep warm.. Can occur even in mild weather. Cool and windy conditions are particularly dangerous. • Prevention – keep warm and stay dry. Eat plenty of energy foods (nuts, dried fruit, peanut butter) • Signs – Victim may begin shivering, then stop as they get colder. Irritability, sleepiness, incoherence, disorientation, inability to think clearly. • Treatment – move victim to warm shelter, remove damp clothing, warm person with blankets, cover head with warm hat or covering, offer hot drinks. Severe hypothermia requires immediate medical attention. • Dehydration –Can happen even in cold weather. Stay hydrated • If you or someone observing with you begins to have trouble with the weather, remember your first aid and use the same treatments you would use for hypothermia, heat exhaustion, etc. as you would on a scout campout. • Prepare for bugs (both the biting, stinging kind and the kind that will crawl up your leg and imbed themselves in you) with bug spray, long pants and shirts. Mosquitoes are just as active at night as during the day.

12. Observing Safety - Location • Most of us can’t see in the dark and when we’re observing, we don’t want to ruin our night vision. This can lead to problems if there are hazards in the area where we’ll be observing • Check the observing area during the daytime for holes, dropoffs, pipes sticking out of the ground, etc. Make note of them so that you won’t find them accidentally in the dark.

13. Observing Safety – Don’ts • Observing the sun - You don’t look at the sun through a telescope for two primary reasons • Blindness - It will permanently blind you by burning your retina. The lenses in a telescope are specifically designed to focus light to a small point. The rays of the sun are very powerful and when focused to a point, can create tremendous heat in a small amount of time. Anyone who has lit paper on fire with a magnifying glass knows how this works. • Telescope Damage - The inside of the telescope is sealed and cannot vent heat. If the inside gets too hot, the lenses can be damaged. The adhesive that secures the lens pieces together can melt and ruin the view. There are special filters that can be used with a telescope for solar viewing, but it is not advisable for an amateur to attempt to do this. Plus, they’re really expensive.

14. Astronomy Definitions Astronomy Merit Badge

15. Astronomy Definitions Star – a hot glowing ball of gas that produces energy by nuclear reactions in its core. Planet – large, non-luminescent, sperical body that orbits a star Rotate – spin around an axis. Revolve – go around another object (orbit) Meteor terminology Meteoroid - small rock that orbits the sun. It’s a meteoroid while it’s in space Meteor – rock from space that hits the earth’s atmosphere and flashes (shooting start, meteor shower) Meteorite - rock from space that hits the ground and remains intact. Moon – small body that orbits a planet. Asteroid – Large rocky body in space that orbits the sun. In our solar system, we have a large number of these in the Asteroid belt Comet – Icy object from outer solar system. When it comes close to the sun it grows a tail of steamed off ice. Solar System – Collection of planets, moons, comets, asteroids, etc. that orbit a star

16. Astronomy Definitions Constellation - a pattern of stars in the sky. Early astronomers (Ancient Greeks, Sumerians, Egyptians, etc.) drew imaginary lines between stars to form images of mythological characters or familiar creatures. There are 88 recognized constellations. Asterism – a portion of a constellation Star Cluster – small group of stars within a galaxy Galaxy – A system of millions or billions of stars, together with gas and dust, held together by gravitational attraction Milky Way – Not just a chocolate bar - Our own galaxy Red Giant – Old star that has bloated up several thousand times its original size White Dwarf – The remnant of a relatively small star that isn’t big enough to go supernova. Very dense Neutron Star- The highly dense core of a star left over after a supernova, but not dense enough to form a black hole. Black Hole – Very massive star that has gone supernova and then collapsed back in on itself and become so dense that even light can’t escape. Universe – Everything that exists

17. All about the Moon Astronomy Merit Badge

18. Where did the moon come from? • It is believed that our moon resulted from a collision with another body (about ½- ¾ the size of Earth) that combined the two large bodies and kicked off a bunch of molten rock that formed the moon. So the impetus for the moon’s current orbit came from that original collision. • The orbit of the moon around our planet is elliptical (not a perfect circle) so the distance between Earth and moon can vary. • Apogee – when the moon is farthest away from Earth • Perigee – when the moon is at its closest to the earth

19. The Moon – Orbit Note the difference in distance between perigee and apogee

20. How does the Moon stay in orbit? What is an Orbit? An orbit is falling without hitting the ground • Place a cannon on a mountain • When the cannon fires, the cannonball will follow its “ballistic trajectory” and hit the ground • Use more gunpowder and the cannonball will flyfurther before it hits the ground • If you use enough gunpowder, the cannonball will flyso far that it NEVER hits the ground. The earth curves away at the same rate that the cannonball drops.The cannonball is in orbit! • The moon orbits the Earth because it’s going fast • enough that it falls continuously without hitting the ground.

21. The Moon – Lunar Features Close Up of Lunar Features with Labels Naked-eye View (What you see in the sky)

22. The Moon – Phases • Phases of moon: • New moon (moon is between Earth and the sun) • Crescent (waxing when growing, waning when getting smaller) • First quarter – half of the moon is illuminated. It’s called first quarter rather than half moon because the moon is ¼ through it’s entire cycle at this point. • Full Moon (Earth is between moon and the sun) • Gibbous – greater than quarter moon (more than half illuminated) (waxing and waning)

23. Lunar Phases • Moon takes 28 days to orbit the Earth and 28 days to rotate once on its axis so the same side always faces the earth. The Far Side of the moon was never seen until space probes took photos in the 1960s • Moon moves slowly eastward over successive nights. As it does so, it becomes increasingly illuminated by the sun until it is completely illuminated at the full moon. • At full moon, it is completely opposite the sun in the night sky. • Note that the moon also moves higher and lower in the sky through each cycle. This is why it’s possible for the moon to eclipse the sun (or the Earth to eclipse the moon) on occasion, but it doesn’t happen every month.

24. Lunar Phases – more detail The outer ring of moon images shows how the moon is seen from Earth. The inner ring of moon images shows the moon’s orientation to Earth and sun

25. The Moon – Total Solar Eclipse Total solar eclipse – when the moon gets between the sun and the earth and completely blocks the light. This only happens in a small path along the earth’s surface, not the whole planet. The moon is too small and too far away to completely block all light to the earth.

26. The Moon – Total Solar Eclipse • The last total solar eclipse visible from the continental U.S.A. occurred on Feb. 26, 1979 (your merit badge counselor remembers this one). • The next two total solar eclipses visible from the U.S.A. occur on Aug. 21, 2017 and Apr. 8, 2024.

27. The Moon – Partial solar eclipse Partial solar eclipse – (also called an “annular” eclipse) occurs when the moon is farther from the earth (lunar apogee) and closer to the sun. The moon’s shadow does not completely cover the sun (see picture below for annular eclipse).

28. The Moon –

29. The Planets Astronomy Merit Badge

30. The Planets • What are the 5 most visible planets? • Mercury • Venus • Mars • Jupiter • Saturn

31. The Planets • The other planets (Neptune, Uranus, Pluto) are so far away that they are not visible to the naked eye. They weren’t even discovered until the last couple of centuries (Uranus 1780, Neptune 1846, Pluto 1930).

32. The PlanetsInferior vs. Superior planets What is an inferior planet? • Any planet between us and the sun What is a superior planet? • Any planet beyond Earth’s orbit Name the inferior planets: • Mercury • Venus Name the superior planets: • Mars • Jupiter • Saturn • Uranus • Neptune • Pluto (unofficially)

33. The PlanetsInferior vs. Superior planets Other than their position relative to Earth, what is the difference between Inferior and Superior planets? Because Inferior planets are closer to the sun than we are, they can get between us and the sun and we can see their “darkside”. This means that the Inferior planets can have phases, much like our moon. Since Superior planets are farther away from the sun than we are, we can never see their darksides (because the dark side is always facing away from us). As a result, we never see phases on Superior planets.

34. The Planets Phases of Venus This is a photo collage of the planet Venus as it travels from our side of the sun to the far side. Note that the planet shows phases similar to our moon. The crescents at top are very large because Venus was closer to us at that point. The full disks at bottom are smaller as Venus gets farther away but more sun can shine on them so we see a disk.

35. The Sun Astronomy Merit Badge

36. Layers of the sun • Core – center – where reactions take place The Sun Corona Chromosphere • Radiative zone – where energy leaves the core Photosphere Convective Zone • Convective zone – where energy is carried by rising and falling currents of hot gas called convective cells. Radiative Zone Core • Photosphere – outer surface • Chromosphere – in violent motion, reddish rim during solar eclipses. • Corona (crown) – extends outward from the sun in the form of the solar wind.

37. What are Sunspots? • Sunspots are temporary phenomena on the photosphere of the Sun that appear as dark spots. These spots are cooler than the surrounding area, but only by comparison (4500K vs. 5800K). • They are caused by intense magnetic activity, which prevents the hotter gases from welling up from underneath. • Some sunspots are so large they can be viewed from Earth without a telescope (e.g. using a pinhole camera). The Chinese were studying them thousands of years ago, long before telescopes were invented.

38. Sunspot Cycles • Sunspot appearances fluctuate over a regular 11 year cycle. Sunspot activity can vary over long periods of time (i.e. there were more sunspots on avg from 1900-1960 and fewer from 1960-present). • Sunspots were rarely observed during the Maunder Minimum (1645-1715) which coincided with a cooling period called the Little Ice Age. This may suggest that sunspots actually indicate an increase in solar output and can directly affect our weather. • Sunspots (called starspots) have even been observed on other stars

39. Sunspots-Effects on Earth • Studies of rock strata (layers) have suggested that the solar cycles have been active for hundreds of millions of years, if not longer; precambrian sedimentary rock has revealed changes in layer thickness, with a pattern approximately repeating every eleven layers. • Analysis of tree rings has revealed a detailed picture of past solar sunspot cycles for the last 11,400 years • Sunspot activity affects weather and plant growth

40. Why do sunspots last so long? • Recent observations from the Solar and Heliospheric Observatory (SOHO) using sound waves traveling below the Sun's photosphere have been used to study the internal structure of sunspots. This analysis shows that sunspots behave like terrestrial hurricanes. This explains why they don’t just appear and disappear, but instead, last for weeks at a time.

41. Solar Flares – What are they? • A solar flare is a brief eruption of intense high-energy radiation from the sun's surface. This explosion is accompanied by a burst of charged particles. • Flares occur in active regions around sunspots • Flares are powered by the sudden release of magnetic energy stored in the corona. • The background picture shows a solar flare (on left) and the resulting prominence (on right)

42. Solar Flares • The first solar flare observed by humans was seen in September of 1859 by astronomers who were observing sunspots. It was so big that it was visible to the naked eye and is considered one of the most powerful on record. • The flare interrupted electrical telegraph service and caused visible aurorae as far south as Havana, Cuba. • The background picture shows a massive flare eruption (on right) in filtered light.

43. Solar Flares • In June of 2011, scientists witnessed the most powerful solar eruption ever seen. A very large amount of material lofted up, expanded, and fell back down over half the surface area of the sun (as seen in the background picture on this slide). • When flares occur, they simultaneously launch a large quantity of particles through the solar corona and into space. This is called a coronal mass ejection (CME). It takes 1-2 days for this to reach Earth. • If one of these powerful flares—and its coronal mass ejection—were to face Earth, the particles would pound satellite components with charged particles, short some out, and potentially cripple them. The particles can also effect telephone and electrical lines.

44. Earth’s Axial Tilt • Because of the axial tilt of the Earth, the amount of sunlight reaching any given point on the surface varies over the course of the year. This results in seasonal change in climate. • Ironically, in the summertime in the Northern hemisphere, the sun is farthest away from us..

45. Stars and Constellations Astronomy Merit Badge

46. The Zodiac Constellations • What’s special about Zodiac constellations? They are centered on the plane of the ecliptic which is the path that the sun, moon, and planets appear to follow in the sky. This is basically the plane of the solar system. These constellations have been misused by astrologers to foretell the future and classify people’s personalities based on their birth date. It doesn’t work. Astrology is bunk. • Trivial note: If you know your Zodiac sign, that is the constellation that the sun is in during your birth month. At least, that was the case about 2500 years ago. Since then, things have shifted around a bit and the sun is now about 1 constellation off from that. Further proof that astrology is bunk because your Zodiac sign is actually one off from what you think it is.

47. The Zodiac Constellations

48. Zodiac Constellations and the Plane of the Ecliptic Diagram of the Sun’s path through the plane of the ecliptic

49. Zodiac Constellations • Spring: Gemini, Cancer, Leo, Virgo, Libra • Summer: Libra (scales), Scorpius, Sagittarius, Capricornus, Aquarius • Fall: Capricornus, Aquarius, Pisces, Taurus, Gemini, Aries • Winter: Gemini, Taurus, Pisces, Aquarius Let’s take a closeup look at a some of these Zodiac constellations. On the next few slides, you’ll see the outline of a constellation. Click on that and you’ll see a picture that shows you what the ancient astronomers saw in that constellation.

50. Leo the Lion (Spring)