3-28-13

Vinnie Caringella

Astronomy

3-28-13

Quiz 15

1.The Sun shines because it sends out energy in all directions as radiation. This radiation takes the form of light and heat.

2. Core, radiation zone, convection zone, photosphere, chromosphere, and corona.

3. When the gravitational equilibrium and energy balance together act as a thermostat to regulate the core temperature because the fusion rate is sensitive to temperature.

4. By randomly bouncing photons carrying it through the radiation zone. 

5. A nuclear reaction in which a heavy nucleus splits spontaneously or on impact with another particle with the release of energy.

6. Yes

7. Yes

8. No

9. Helium

10. 0.7%

Tiny Primitive Mammal Unearthed in Japan: Scientific American

Tiny Primitive Mammal Unearthed in Japan: Scientific American:

"The discovery of the jaw of a 112-million-year-old mammal from the early Cretaceous Period suggests that small creatures were already evolving quickly"

'via Blog this'

Speed Of Light In Vacuum Is Not Actually Constant, Study Finds | Popular Science

Speed Of Light In Vacuum Is Not Actually Constant, Study Finds | Popular Science:

"Can you trust nothing in life? A new physics paper suggests that the speed of light in a vacuum may not be constant, and that a vacuum isn't actually entirely empty of stuff."

'via Blog this'

Quiz

1. How do we know what is happening inside the Sun?
2. What causes solar activity?
3. How does solar activity vary with time?
4. Do neutrinos have mass?
5. Do we get neutrinos from the Sun?
6. What did Ray Davis got the Nobel prize for?
7. How long is the sunspot cycle?
8. Why are sunspots cooler?
9. Are there magnetic fields in the Sun?
10. What is the solar wind?

Hint: Read on the Solar Neutrino Problem in Wikipedia

Quiz 03/28/2013

1. Why does the Sun shine? The Sun shines because it sends out energy in all directions as radiation. This radiation takes the form of light and heat.
2. What is the Sun's structure? Core, radiation zone, convection zone, photosphere, chromosphere, and corona.
3. How does nuclear fusion occur in the Sun? When the gravitational equilibrium and energy balance together act as a thermostat to regulate the core temperature because the fusion rate is sensitive to temperature.
4. How does the energy from fusion get out of the Sun? By randomly bouncing photons carrying it through the radiation zone. 
5. What is nuclear fission? A nuclear reaction in which a heavy nucleus splits spontaneously or on impact with another particle with the release of energy.
6. Are neutrinos formed in nuclear fusion? Yes
7. Are photons created in nuclear fusion? Yes
8. Does the Sun have the same temperature throughout? No
9. Which element is created in the Sun? Helium
10. What fraction of mass is converted into energy in the Sun's core? 0.7%

QUIZ - 3.28.13

1. Why does the Sun shine?

• The Sun shines steadily because nuclear fusion in the core maintains both gravitational equilibrium between pressure and gravity and energy balance between thermal energy released in core and radiative energy lost from the Sun's surface. The chemical and gravitational energy sources could not explain how the Sun could sustain its luminosity for more than about 25 million years.

2. What is the Sun's structure?

• The Sun's structure is:
• From inside out, the layers are.....
• Core
• Radiation Zone
• Convection Zone
• Photosphere
• Chromosphere
• Corona

3. How does nuclear fusion occur in the Sun?

• The nuclear fusions occurs in the Sun when the graviational equilibrium and energy balance together act as a thermostat to regulate the core temperature because the fusion rate is very sensitive to temperature. The core's extreme temperature and density are just right for the nuclear fusion of hydrogen to helium through the proton-proton chain.

4. How does the energy from fusion get out of the Sun?

• The energy from fusion gets out of the Sun by randomly bouncing photons carrying it through the radiation zone. The rising of hot plasma carries energy through the convection zone to the photosphere.

5. What is nuclear fission?

• Nuclear fission is either a nuclear reaction / radioactive decay proccess in which a heavy nucleus (such as uranium) splits into two equal and lighter nuclei, either spontaneously or as a result  of the impact of a particle, often producing free neutrons and photons (in the form of gamma rays) and releasing a very large amount of energy. (and possible some other radioactive particles as well) The two nuclei produced are most often of comparable but slightly different sizes, typically with a mass ratio  of products of about 3 to 2.
• Most fissions are binary fissions, producing two charged fragments, but occasionally 2 to 4 times per 1,000 events.
• Three positively charged fragments are produced in a ternary fission. The smallest of these fragments in ternary processes ranges in size from a proton to an argon nucleus.

6. Are neutrinos formed in nuclear fusion?

• YES, neutrinos are formed in nuclear fusion.

7. Are photons created in nuclear fusion?

• YES, photons are created in nuclear fusion.

8. Does the Sun have the same temperature throughout?

• NO, the Sun does not have the same temperature throughout.

9. Which element is created in the Sun?

• The element, Helium, is created in the Sun.

10. What fraction of mass is converted into energy in the Sun's core?

• At the absolute most, only 0.7% of the mass is converted into energy, in the Sun's core. The actual expected amount of mass, to get converted into energy, is around 0.07%.

Quiz

1. Why does the Sun shine? 
2. What is the Sun's structure? 
3. How does nuclear fusion occur in the Sun? 
4. How does the energy from fusion get out of the Sun? 
5. What is nuclear fission? 
6. Are neutrinos formed in nuclear fusion? 
7. Are photons created in nuclear fusion? 
8. Does the Sun have the same temperature throughout? 
9. Which element is created in the Sun? 
10. What fraction of mass is converted into energy in the Sun's core?

Chapter 10 Notes

Weight of upper layers compresses lower layers.

Gravitational equilibrium

            Gravity pulling in balances pressure pushing out.

Energy balance

            Thermal energy released by fusion in core balances radioactive energy lost from surface.

Gravitational contraction

            Provided energy that heated the core as the sun was forming.

            Contraction stopped when fusion started replacing the energy radiated into space.

Radius: 6.9 x 10^8. 109 times earth

Mass: 2 x 10^30kg. 300,000 earths

Luminosity: 3.8 x 10^26 watts

Solar wind

            A flow of charged particles from the surface of the suns.

Corona

            Outermost layer of solar atmosphere.

Chromosphere

            Middle layer of solar atmosphere.

Photosphere

            Visible surface of the sun.

Convection zone

            Energy transported upward by rising hot gas.

Core

            Energy generated by nuclear fusion

Fission

            Big nucleus splits into smalls pieces

Fusion

            Two pieces stick together

The sun releases energy by fusing four hydrogen nuclei into one helium nucleus.

Midterm

1. A
2. B
3. C
4. D
5. A
6. B
7. C
8. D
9. A
10. B

Chapter 10 Transparency 5

Chapter 10 Transparency 4

Chapter 10 Transparency 3

Chapter 10 Transparency 2

Chapter 10 Transparency 1

QUIZ - 3.15.13

1. Have we ever witnessed a major impact?

• YES, the most recent major impact happened in 1994. Fragments of comet SL9 hit Jupiter.

2. Did an impact kill the dinosaurs?

• YES, an iridium layer just about dinosaur fossils suggests that an impact caused mass extinction 65 million years ago. A large crater of that age has been found in Mexico.

3. Is the impact threat a real danger or just media hype?

• Large impacts do happen, but they are rare. They can cause major extinctions about every 100 million years.

4. How do other planets affect impact rates and life on Earth?

• Jovian Planets sometimes deflect comets toward Earth but send many more out to the Oort Cloud.

5. Which chapter of "The Universe Within", deals with the Chicxulub event?

• Chapter # 7 , from "The Universe Within", deals with the Chicxulub event.

6. Who was Luis Alvarez?

• Luis Walter Alvarez was an American experimental physicist and inventor, who was awarded the Nobel Prize in Physics in 1968. With his son, geologist Walter Alvarez, proposed the Alvarez Hypothesis. The Alvarez Hypothesis sought to explain the extinction event that wiped out the dinosaurs as the result of an asteroid impact.

7. Who was Walter Alvarez?

• Walter Alvarez was is a professor in the Earth and Planetary Science department at the University of California, Berkeley. He is most widely known for the theory that dinosaurs were killed by an asteroid impact. He developed this theory in collaboration with his father, Nobel Prize winning physicist Luis Alvarez.

8. What is SL9?

• SL9, also know as Comet Shoemaker - Levy 9 (D/1993 F2) was a comet that broke apart and collided with Jupiter in July 1994, providing the first direct observation of an extraterrestrial collision of Solar System objects.

9. Which planet of the solar system has the biggest mass, and therefore changes orbits of asteroids and comets the most?

• The planet of the solar system that has the biggest mass, and therefore changes orbits of asteroids and comets the most is Jupiter.

10. Where do interlopers to the inner solar system more likely get thrown out?

• Interlopes pass once through the inner solar system before getting thrown out.

Midterm

1. Have we ever witnessed a major impact?

a) The most recent major impact happened in 1994, when fragments of comet SL9 hit Jupiter

b) No

c) Sixty five millions years ago a meteorite killed the dinosaurs

d) A huge impact caused the Moon to form

    2. Why are Jupiter's Galilean moons geologically active?

a) They have continental drift

b) Tidal heating drives activity, leading to Io's volcanoes and ice geology on other moons

c) The cores of these moons are highly radioactive

d) Meteorites produce volcanoes

  3. What geological processes shape Earth's surface?

a) Only water flow

b) Only the wind

c) Impact cratering, volcanism, tectonics, and erosion

d) Only impacts

 4. What theory best explains the features of our solar system?

a) The evolution theory of Charles Darwin

b) The Bohr model

c) The nebular theory, which holds that our solar system formed from a cloud of planets, and a star

d) The nebular theory, which holds that our solar system formed from a cloud of interstellar gas, explains the general features of our solar system 

 5. Where did asteroids and comets come from?

a) They are leftover planetesimals, according to the nebular theory

b) They are extinct planets

c) They are extinct stars

d) They are remnants of a Black Hole

 6. What is matter?

a) Made mainly of neutrinos 

b) Ordinary matter is made of atoms, which are made of protons, neutrons, and electrons

c) Made of tachyons

d) Made of axions 

 7. What are the three basic types of spectra?

a) Convection, conduction, and radiation

b) Red, green, and blue

c) Continuous spectrum, emission line spectrum, and absorption line spectrum

d) Hydrogen, Helium, and Lithium

  8. What keeps a planet rotating and orbiting the Sun?

a) The mass of the Sun

b) The mass of the planet

c) The law of inertia

d) Conservation of angular momentum

  9. Write down Newton's formula for the force of gravity.

a)

b)                                                                 

c)                                                               

d)                                                               

  10.  How did astronomical observations benefit ancient societies?

a) Allow them to predict war winners

b) Keeping track of time and seasons; navigation

c) Allow them to know the future names of kings

d) That way they knew the numbers of the winning lottery tickets 

In Asteroid’s Aftermath, a Sigh of Relief

Images from Stefan Geens and Ogle Earth via Google Earth and YouTube (top and bottom rows); NASA (center); Jorge Zuluaga and Ignacio Ferrín via arXiv (middle row sides)

Crowd-sourced video, information from Google Earth and data from nuclear test-ban sensors provided information about a small asteroid that exploded last month near Chelyabinsk, Russia.

By HENRY FOUNTAIN

Published: March 25, 2013

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Using an eclectic mix of crowd-sourced video, information from Google Earth and data from nuclear test-ban sensors, scientists have gotten a much more accurate picture of the small asteroid that exploded near the Russian city of Chelyabinsk last month.

Science Times Podcast

Henry Fountain on how science is tracking the meteor that exploded over Russia back to its source; Mary Roach on our fascinating guts; Denise Grady on a novel treatment for some cancers of the blood.

• 0:25

  Introduction

  • play
  • max volume

  0:25
• 8:00

  A Meteor’s Data Trail

• 11:22

  Journey on the Alimentary Canal

• 9:07

  Using the Body to Fight Cancer

Multimedia

Multimedia Feature

A Meteor Streaking Through the Sky From Six Vantage Points

A Meteorite Rush

Related

• Better Asteroid Detection Is Needed, Experts Say (March 21, 2013)

• Shock Wave of Fireball Meteor Rattles Siberia, Injuring 1,200(February 16, 2013)

Connect With Us on Social Media

@nytimesscienceon Twitter.

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But what is most clear is that while Chelyabinsk did not exactly dodge a bullet on Feb. 15, the city was fortunate to be only grazed by it. “The people of Chelyabinsk were very lucky,” Edward Lu, a former astronaut who now leads the B612 Foundation, a private initiative to detect similar asteroids, said at a Congressional hearing last week about the space threats.

The Russian meteor — which, according to the latest estimates, was about 60 feet in diameter and came in undetected at roughly 42,000 miles an hour — was almost 15 miles high when it blew apart. There were no deaths, and most of the 1,500 injuries were from glass as windows shattered when a shock wave hit the city 88 seconds later.

“If it had detonated closer to the ground, it would have been worse,” said Margaret Campbell-Brown, a member of a team of researchers at the University of Western Ontariowho have analyzed the meteor’s orbit and characteristics of the blast. It also helped that the meteor was a stony one — what scientists call an ordinary chondrite — and not a rarer iron-nickel one, in which case it might have reached the ground before exploding.

The blast was the largest fireball since the Tunguska eventof 1908, and as videos from surveillance, car-mounted and cellphone cameras quickly began to be posted online, it became apparent that this explosion would be studied like no other, with scientists and amateur bloggers alike rushing to analyze the images.

The Tunguska event involved the detonation of what is generally thought to be a meteor over a remote part of central Siberia. That object may have entered the atmosphere at a steeper angle than the Chelyabinsk meteor — which came in at an angle of less than 20 degrees from horizontal — and exploded about five miles above the ground. The lower altitude, as well as the larger size of the Tunguska rock, help explain why it had a much greater impact, flattening trees over an area the size of metropolitan Washington.

Still, the Canadian team has calculated that the energy released in the Chelyabinsk explosion was the equivalent of about 440 kilotons of TNT, or about 30 times the power of the Hiroshima bomb.

That calculation was made with the help of data from a network of acoustic sensors set up to monitor compliance with the treaty to ban nuclear weapons testing. There are about 45 of the sensors worldwide, detecting so-called infrasound at frequencies well below the range of human hearing.

Thomas Mützelburg, a spokesman for the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, which is based in Vienna, said the explosion was detected by more than 20 of the sensors, including one in Antarctica nearly 10,000 miles from Chelyabinsk. Low-frequency sounds do not dissipate easily, so some of the detectors picked up the explosion more than once as the sound circled the globe several times.

With knowledge of the energy and information about how fast the meteor was traveling, researchers were then able to calculate the mass of the meteor, about 11,000 metric tons. “It’s all about the kinetic energy of that body,” which is related to its mass and velocity, said Richard P. Binzel, a planetary scientist at the Massachusetts Institute of Technology.

The meteor has a certain amount of energy as it enters the atmosphere, Dr. Binzel said. As it hits the air, it starts to decelerate quickly, and then the stress differential between the superpressurized air in front and the less-pressurized air behind causes the rock to break apart violently. “All that kinetic energy has to be released,” he said. Only small fragments of the meteor reached the ground, and some have been brought to laboratories in the United States, including the Institute for Rock Magnetism at the University of Minnesota, where a Russian scientist is studying their magnetic properties.

Like other teams, the Canadian researchers have used video images of the meteor’s east-to-west trail above Chelyabinsk to help calculate its trajectory and orbit. Since the explosion occurred in daylight, Dr. Campbell-Brown said they asked a colleague there to take night photographs from the same locations. By superimposing the images of the meteor’s path over the night images containing stars, the researchers should be able to plot the path even more accurately.

For now, though, they and other teams, including one from the University of Antioquia in Medellín, Colombia, have established that the meteor originated in the inner part of the asteroid belt, in a regular, harmless orbit around the Sun between Mars and Jupiter. How it came to have an irregular Earth-crossing orbit is not known, but like other Earth crossers it was probably affected by the gravity of Jupiter or another planet at some point. It then circled the Sun every 18 months in a highly eccentric orbit — more than two and a half times the Earth-Sun distance at its farthest, close to the orbit of Venus at its nearest — before it smacked into the Earth’s atmosphere.

Jorge Zuluaga, a member of the Colombian group, said he was inspired by work done soon after the event by Stefan Geens, a blogger in Stockholm. Mr. Geens used several videos — including one from a camera in Revolution Square in central Chelyabinsk — to triangulate the path. The video does not show the explosion directly, but rather the shadows of lampposts (and of a huge statue of Lenin), which moved like the shadow on a sundial as the fireball crossed the sky.

Using Google Earth, it is easy to pinpoint the coordinates of the Revolution Square camera and others. Dr. Zuluaga said that his team, which included Mr. Geens as a co-author on its most recent paper, is working to improve its calculations by, among other things, learning about the optics of the various video cameras. “We are trying to understand the distortion we have,” he said.

Dr. Zuluaga thinks that eventually it will be possible to reconstruct the rock’s orbit so precisely that researchers may be able to detect it retroactively, by poring over images from sky-surveying telescopes taken the last time it flew near the Earth. “Then we can assign it a name,” he said. “It doesn’t have one now, because it’s a dead asteroid.”

In addition to helping scientists plot the meteor’s path, the videos that were posted online contributed to a surge in interest in projects to detect asteroids before they strike Earth. In an interview after his Congressional testimony, Dr. Lu said his foundation, which wants to put a privately financed telescope in space within five years, had seen an increase in donations since the explosion.

“It made it more real to folks,” he said. “There’s nothing like a hundred YouTube videos to do that.”

Before the Midterm

I want all of you to know that you have done good work. Tomorrow you are going to turn in your test. I will post it soon; with a multiple choice format. Before I do that though, I want you to know that knowledge acquisition has changed in the past few years. I try through my course, to tell you how.

There are multiple sources of knowledge, like Wikipedia. There are multiple platforms like this one provided by Google. You need to master these tools, this is a requirement for modern jobs. We are in a knowledge economy now. I posted an article from the NYT about a movement to ask the students to bring their own technology.

I expect you to be more knowledgeable than myself in the use of these new devices. Whoever was born after 1981 has grown up with new toys, which allow new ways of learning.

I will post the midterm today around 5:00 PM.

Quizzes 13,14 Answers

1. Why is there an asteroid belt?
2. How are meteorites related to asteroids?
3. How do comets get their tails?
4. Where do comets come from?
5. How big can a comet be?
6. What are Pluto and other large objects of the Kuiper belt like?
7. Can a meteorite hit Earth?
8. Name a few comets.
9. What is comet PANSTARRS?
10. Was the meteorite in Russia last month previously an asteroid?

Hint: Check Wikipedia

1. Have we ever witnessed a major impact?
2. Did an impact kill the dinosaurs?
3. Is the impact threat a real danger or just media hype?
4. How do other planets affect impact rates and life on Earth?
5. Which chapter of "The Universe Within", deals with the Chicxulub event?
6. Who was Luis Alvarez?
7. Who was Walter Alvarez?
8. What is SL9?
9. Which planet of the solar system has the biggest mass, and therefore changes orbits of asteroids and comets the most?
10. Where do interlopers to the inner solar system more likely get thrown out?

Hint: Check Amazon.com, and my book report [here].

Quiz 12 Answers

1. What are jovian planets made of?
2. What are jovian planets like on the inside?
3. What is the weather like on jovian planets?
4. What kinds of moons orbit the jovian planets?
5. Why are Jupiter's Galilean moons geologically active?
6. What geological activity do we see on Titan and other moons?
7. Why are jovian moons more geologically active than small rocky planets?
8. What are Saturn's rings like?
9. Why do the jovian planets have rings?
10. Who predicted volcanoes on Io?

Hint: Look up Io (moon) on Wikipedia.

Quizzes 10,11 Answers

1. Why is Earth geologically active?
2. What processes shape Earth's surface?
3. How does Earth's atmosphere affect the planet?
4. Was there ever geological activity on the Moon or Mercury?
5. Who was Evangelista Torricelli?
6. What is plate tectonics?
7. Is there heat inside Earth?
8. What is convection?
9. What is conduction?
10. What is  radiation?

Hint: Use Wikipedia

1. What geological features tell us that water once flowed on Mars?
2. Why did Mars change?
3. Is Venus geologically active?
4. Why is Venus so hot?
5. What unique features of Earth are important for life?
6. How is human activity changing our planet?
7. What makes a planet habitable?
8. Was there a volcano born last century on Earth?
9. Which country witnessed a new volcano on February 20, 1943?
10. Who was working on the field when the volcano was born?

Hint: Use Wikipedia (Paricutin)

Quizzes 8,9 Answers

1. What does the solar system look like?
2. What features of our solar system provide clues to how it formed?
3. What theory best explains the features of our solar system?
4. Where did the solar system come from?
5. What caused the orderly patterns of motion in our solar system?
6. Why are there two major types of planets?
7. Where did asteroids and comets come from?
8. How do we explain the existence of our Moon and other exceptions to the rules?
9. When did our planets form?
10. When was Nicolaus Copernicus born?

1. How do we detect planets around other stars?
2. How do extrasolar planets compare with planets in our solar system?
3. Do we need to modify our theory of solar system formation?
4. What is a Hot Jupiter? 
5. Do extrasolar systems have a frost line?
6. Define the frost line
7. On which side of the frost line is Earth?
8. On which side of the frost line is Jupiter?
9. What is a meteorite?
10. What hit Russia last Friday, February 15, 2013?