History Of Astronomy Chapter 12

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1. What is the van Karman line? What was the first man-made object to breach it? Who designed this object, and where did he end up working?

Back 1

It is a line 100km above sea level, the boundary at which Earth’s atmosphere is
too thin for air navigation. The V2 rocket, a German WWII missile, became the
1st man-made object to breach the Karman line. Werner von Braun (forced into
Nazi party) designed the V2. He later became one of the architects of the
American space program.

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2. How were the 1st photographs of Earth taken from space?

Back 2

V2 rockets were used by the US military to take the 1st photos from space, they
attached a camera to the rocket.

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3. What kinds of animals were first launched into space by the U.S (after the fruit flies)? What about the Soviet Union?

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The U.S. sent monkeys into space, very few survived. The Soviet Union was sending dogs into space, they had more success with the dogs than the US had with monkeys, mostly due to less technical problems.

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4. Which country launched the first satellite into Earth-orbit, and what was this satellite called?

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The soviet union launched the first satellite, it was called Sputnik 1

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5. Which country launched the 1st human into space? Describe how this trip was made.

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The United States launched the 1st human into space. They created a space pod with no controls, not meant to be piloted. A single person would be placed in the pod, attached to the nose of a rocket, launched into space, ejected and would land back on earth.

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6. Which country made the first unmanned landings and orbits of the Moon? What did the Luna 3 take photographs of for the 1st time?

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The Soviet landed 3 Luna crafts and took photographs of the moon`s far side

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7. Why can't we see the far side of the Moon from Earth? Why is the far side more cratered than the near side?

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We can’t see the far side of the Moon from Earth due to the Moon`s synchronous orbit, its rotation period is equal to its orbital period. The far side is more cratered as craters on the near side have been filled with lava and solidified into maria, likely due to the Earth`s gravitational pull on the lava when it was still liquid

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8. Which country made the first manned landing on the Moon? What was this name of the astronaut who first stepped on the Moon?

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The United States landed Apollo 11 on the Moon, and astronaut Neil Armstrong becomes the first human to walk on the Moon

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9. What is an orbiter? What is a lander? What is a rover?

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-An orbiter goes into orbit around a planet or moon, intended to study a large area of a planet or moon ex. Its atmosphere
-a lander lands on planet at a specific location and stays in that location to study
the area around it
- Rovers are dropped by orbiters onto a planet, rovers move around on a planet`s surface

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10. Which planets in our solar system have been landed on by human-made crafts? Were these missions manned or unmanned?

Back 10

Venus: unmanned, probe.
Mars: unmanned, rover and probes.

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11. What did NASA's Space Shuttle consist of? What was its purpose?

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It consisted of a rocket, orbiter & re-entry spaceplane . It completed over 100 missions such as satellite maintenance, space experiments and trips to the International Space Station

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12. What is the International Space Station? What is its purpose?

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A habitable satellite for conducting space experiments. It was launched into Earth-orbit in a joint-effort by 5 space agencies. It has been continuously occupied for over 10 years. The station is suited for the testing of spacecraft systems and equipment required for missions to the Moon and Mars.

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13. What is the Canadarm? Where are Canadarms permanently installed, and what is their purpose?

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It is a 15 metre robotic arm and was used in a Space shuttle mission. Canadarms have now been used in over 50 shuttle missions and are currently installed on the International Space Station. It transfers cargo and equipment. On the International Space Station they are used to hold on to astronauts.

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14. What have our space missions left behind around the Earth?

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The world`s satellites and space missions have created a shell of debris around the Earth. Now estimated in the tens of millions, the debris includes defunct satellites, equipment & collision fragments

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15. What discovery was made when Pete Conrad returned from the Apollo 12 mission to the Moon?

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A camera that had been left on the moon for 2 years contained bacteria from Earth that had survived the Moon’s harsh conditions. This proved: organisms can survive in space

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16. What are extremophiles? What are some of the extreme environments on Earth where extremophiles are found?

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lifeforms which can survive extreme conditions (conditions that can`t sustain human life) Extremophiles are the most likely forms of life to be found on other planets or moons in our solar system. The Antarctic is one example of where extremophiles can be found, salty and acidic composition..

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17. What is the Habitable Zone? Which planets in our solar system are in this zone?

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The distance from a star at which a planet can sustain liquid water on its surface (a necessity for carbon-based life). Earth is the only planet in our sun`s habitable zone.

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18. What is it about the Carbon atom that makes carbon-based life likely?

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Carbon is able to form complex molecules suggesting that carbon-based life is common. They are able to form many bonds and Amino Acids which could form proteins, the building blocks of all living organisms on earth.

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19. What 2 surface features of Mars suggest that it could have supported life in the past, and why? What is it about Mars' atmosphere that makes Earth-like life currently unlikely?

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-Mars’ polar ice caps contain at least 50% water-ice which may have been liquid when the solar system was younger and hotter
-Mars’ canyons are evidence of ancient rivers which may have held primitive life
-There are no carbon atoms so that makes earth-like life on Mars unlikely

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20. What was the mission of the Viking space probes? What was concluded on their return, and why?

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The Viking probes were sent to study soil samples for evidence of carbon-based life. It was concluded that there was no life on Mars since there was no carbon.

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21. What was found when synthesized Martian soil was studied on Earth?

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When synthesized Martian soil was studied on Earth, live micro-organisms were found in the soil.

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22. What is rock ALH 84001? Why does it suggest that life once existed on Mars?

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It was a meteorite containing fossilized micro-organisms which was found to be Martian in origin. It suggested this life could have been possible on Mars in the past.

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23. What evidence of water was found by the Pheonix lander? What about the Opportunity rover? What is the mission of the Curiosity rover?

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The Pheonix lander found water ice, carbon and minerals in a Martian polar region. The Opportunity rover found veins of water-deposited minerals in Martian rocks. The Curiosity rover is expanding the search for evidence of life on Mars by studying the soil beneath the surface

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24. Why was the Galileo spacecraft intentionally crashed into Jupiter?

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Galileo spacecraft was intentionally commanded to crash into Jupiter, which eliminated the possibility it would impact Europa (one of its moons) and seed it with bacteria.

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25. Where is Europa? What is the evidence for liquid water on this celestial body?

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Europa is one of Jupiter’s moons. There is evidence for an ocean underneath its surface, the cracked icy surface on Europa’s surface may be evidence of this.

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26. Where are Titan and Enceladus? What is the evidence for carbon and liquid water on these celestial bodies? What is Titan the only moon in the solar system to possess?

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Titan is one of Saturn’s moons. a NASA orbiter around Saturn sent a probe to the moon Titan, where it found a thick atmosphere, carbon-rich lakes and possible volcanic activity (early Earth-like conditions). It has a lake of liquid methane. Titan is also only the moon in the solar system to have a thick, planet like atmosphere. Enceladus is another one of Saturn’s moons.

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27. What does SETI stand for, and who was its original founder?

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Frank Drake founded the Search for Extraterrestrial Intelligence project (SETI), a program which listens for radio transmissions from intelligent extraterrestrials

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28. What is the mission of SETI's Project Pheonix? Has it been successful so far?

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Project Phoenix uses radio dishes around the world to monitor ~800 nearby Sun-like stars for radio signals from ETs

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29. What does the Drake Equation measure? Can it currently be accurately solved? Why/why not?

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Drake developed the Drake Equation which estimates the # of communicating civilizations in our Galaxy (N). The equation can’t be solved since its terms are mostly unknown, but our knowledge of extra solar planets suggests N>1

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30. Briefly describe the 3 attempts that Earth has made to send messages into space. What were the general contents of each message?

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1. The Arecibo Message (radio message from the Arecibo dish) contained numbers from 1 to 10, atomic number of elements in DNA, chemical formulas that describe the components and composition of DNA, the double helix of DNA, human figure, solar system with sun at right and Earth displaced upward, Arecibo radio telescope and its diameter
2. The Pioneer plaques (engravings on the Pioneer spacecraft) – contains human figures in front of the pioneer craft, also an image of the solar system, also the sun’s location relative to nearest stars , and a number system based off of hydrogen
3. The Voyager Golden Record (record with audio message and engraving on Voyager 1) – engraved message which contains instructions for playing the record, location of the sun relative to nearest stars, the hydrogen communication system and sounds of earth are recorded on the other side of the record

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31. Where is Voyager 1 right now?

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Voyager 1 is ~20 years from reaching interstellar space, making it the furthest man-made object. It will make its closest approach (~2 ly) to a star in 40 000 years

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32. Describe the Doppler-Wobble method for detecting extrasolar planets.

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A planet’s gravity causes its star to wobble around the centre of mass, inducing a regular blueshift and redshift due to the star’s approaching and receding motion. The shift reveals the planet’s period, orbital radius and mass. Monitoring a star’s spectrum for a long period of time can tell us if it has planets orbiting it or not, if the spectrum shifts back and forth , then we know that the star has a planet.

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33. What types of planets are most likely to be found with the Doppler-Wobble method, and why?

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This method tends to detect “Hot Jupiters” (giant gas planets that are near their star) as these planets induce large wobbles.

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34. Why could "Hot Jupiters" not have been born at their present locations? How are they suspected to have reached their present locations?

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Hot Jupiters can’t form close to its star because there is not enough matter, they must have migrated inward.

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35. What is the goal of the Kepler Mission? How will it aid SETI?

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Kepler is a solar orbiting spacecraft capable of finding Earth-size planets via the planetary transit method. Earth size planets may be able to sustain life.

Front 36

36. Describe the method that the Kepler Mission is using to detect extrasolar planets.

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It is using the planetary transit method, the eclipsing of a star by its planet produces a periodic dimming of the star’s light. The period and depth of the dimming reveals the planet’s period, orbital radius, size and temperature. Much easier to find earth like planets from this method than the Doppler wobble method.

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37. Is Kepler surveying a large or small fraction of the stars in the Milky Way? Based on their preliminary results, our Earth-like planets common or rare? Has Kepler found any planet candidates in the Habitable Zone? How about Earth-like planet candidates in the Habitable Zone? How many planets in the Habitable Zone have been projected for our entire Galaxy?

Back 37

- It is surveying a small fraction of stars in the Milky Way only 0.0001% of our galaxy.
- Earth like planets are common.
- Our galaxy alone may contain billions of planets, hundreds of millions with in their star’s habitable zone
- Yes, there may be earth-like planets in the HZ
- Kepler mission revealed 1,235 planet candidates, while 54 of them were orbiting their host star in the so-called "habitable zone".

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38. Describe how planets can be investigated for Earth-like habitability and signs of life.

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Earth-like planets will be “listened to” by SETI for “intelligent” radio signals Spectra of Earth-like planets will be investigated for habitability and potential signs of life. The spectra of a star will be examined while it is being transited by a planet and also while it isn’t being transited and we subtract this spectrum, we can get the spectrum of the exoplanet’s atmosphere.