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PH607lec12
PH607lec12

... Within a few minutes, the flux of a faint source increased by a factor of 5-6 and fainted again after about 30 min. The flare was found to have happened within a few milli-arcseconds of the position of Sgr A*. The short rise-and-decay times told us that the source of the flare was located within les ...
Summary: Nuclear burning in stars
Summary: Nuclear burning in stars

... • Gas, stars closer to center orbit in less time than those farther from center. • Î automatic stretching of any feature into a trailing spiral. • But arms should rapidly wind up and disappear ...
PS 224, Fall 2014 HW 4
PS 224, Fall 2014 HW 4

... 4. Homes to Civilization? We do not yet know how many stars have Earth-like planets, nor do we know the likelihood that such planets might harbor advanced civilizations like our own. However, some stars can probably be ruled out as candidates for advanced civilizations. For example, given that it to ...
The Case against Copernicus
The Case against Copernicus

... appeared to behave, and it fit the available data better than Copernicus’s system did. Brahe was a towering figure. He ran a huge research program with a castlelike observatory, a NASA-like budget, and the finest instruments and best assistants money could buy. It was Brahe’s data on Mars that Johan ...
Outer Planets Review Sheet with answers: 1.) Give the order of the
Outer Planets Review Sheet with answers: 1.) Give the order of the

... b.) The object must have enough mass for its gravity to have pulled it into a sphere shape. c.) The Planet must have cleared its orbit. (The objects orbiting the planet must not combine to make up more than half of the actual planet’s size.) 40.) Which of these rules did Pluto fail? (1 Mark) Pluto f ...
Union College Spring 2016 Astronomy 50 Lab: Diameter of the
Union College Spring 2016 Astronomy 50 Lab: Diameter of the

... (1) and (2) was the distance between two locations that were due North-South of each other, and the locations we are using also have an East-West component to their distance. Consider the location on the Earth that is due South of Schenectady and due East of Playa del Carmen, Mexico. In Figure 7, wh ...
HR Diagram of One Solar Mass Evolution
HR Diagram of One Solar Mass Evolution

Astronomy Club of Asheville October 2016 Sky Events
Astronomy Club of Asheville October 2016 Sky Events

...  Zodiacal light is the sunlight reflected from numerous dust grains located along the plane of the solar system  the ecliptic or “zodiac”.  These dust grains are left over from the formation of the solar system (a type of cosmic dust), and their supply is continuously fed by particles from comets ...
December 2007 Clear Skies Newsletter PDF
December 2007 Clear Skies Newsletter PDF

... mentioned as they play a significant role in the club. Also there is a role of organizer for the annual Island Star Party which Norm Willey has offered to volunteer for and continue to head for the upcomming year. In order to comply with the Societies act we need to fill all 5 director positions. Es ...
Life Cycle of a Star
Life Cycle of a Star

... • Stars begin as a large cloud of gas and dust called a nebula • Once stars are formed they enter the main sequence stage. In this stage they continuously generate energy in the core through nuclear fusion. • Size, structure and composition change very little during this stage. ...
Comets, asteroids, and meteors oh my!
Comets, asteroids, and meteors oh my!

... – Seen once only 76 years – Last seen in 1986 – Next time we will see Halley’s comet will be around 2062 this is a prediction ...
chapter01lecturecdl
chapter01lecturecdl

... • By extending your hand at arm's length, you can approximate a many degree measurements. – Apparent width of one finger at arm's length is about 1o ...
lec01_26sep2011
lec01_26sep2011

The Geology of Disasters
The Geology of Disasters

... 5. Students know the Sun is a typical star and is powered by nuclear reactions, primarily the fusion of hydrogen to form helium. 6. Students know the evidence for the dramatic effects that asteroid impacts have had in shaping the surface of planets and their moons and in mass extinctions of life on ...
Light and shadow from distant worlds
Light and shadow from distant worlds

... are beginning to characterize the properties of their atmospheres. This review concentrates on the bulk properties (masses, radii) and atmospheric compositions of exoplanets, with an eye towards the eventual characterization of a rocky, habitable world. The best summary of exoplanets is their distri ...
The Formation of Planetary Systems
The Formation of Planetary Systems

Science
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... Earth is stationary in the geocentric model but moves around Sun in Sun-centered model. Retrograde motion is real (planets really go backward) in geocentric model but only apparent (planets don’t really turn around) in Suncentered model. Stellar parallax is expected in the Sun-centered model but not ...
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... • Brahe compiled the most accurate (one arcminute) naked eye measurements ever made of planetary positions. • He still could not detect stellar parallax, and thus still thought Earth must be at the center of the solar system (but recognized that other planets go around Sun). • He hired Kepler, who u ...
Testing - Chabot College
Testing - Chabot College

... • Brahe compiled the most accurate (one arcminute) naked eye measurements ever made of planetary positions. • He still could not detect stellar parallax, and thus still thought Earth must be at the center of the solar system (but recognized that other planets go around Sun). • He hired Kepler, who u ...
venus transit vesna
venus transit vesna

... determining the Parallax of the Sun, or his Distance from the Earth; by Dr. Halley, Sec. R. S. N0 348, p.454. Translated from the Latin. It is well known that this distance of the sun from the earth, is supposed different by different astronomers. Ptolemy and his followers, as also Copernicus and Ty ...
Star Gazing
Star Gazing

Lecture5 - Tufts Institute of Cosmology
Lecture5 - Tufts Institute of Cosmology

... of gaseous content • Galaxy is so large that it contains the entire Universe ...
Introduction: - TrevorMander.com
Introduction: - TrevorMander.com

Kinds of Stars
Kinds of Stars

... Pulsating Stars- Change brightness, expand & contract. Example is Cepheid Variables. ...
Complete the following review packet!
Complete the following review packet!

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Rare Earth hypothesis



In planetary astronomy and astrobiology, the Rare Earth Hypothesis argues that the origin of life and the evolution of biological complexity such as sexually reproducing, multicellular organisms on Earth (and, subsequently, human intelligence) required an improbable combination of astrophysical and geological events and circumstances. The hypothesis argues that complex extraterrestrial life is a very improbable phenomenon and likely to be extremely rare. The term ""Rare Earth"" originates from Rare Earth: Why Complex Life Is Uncommon in the Universe (2000), a book by Peter Ward, a geologist and paleontologist, and Donald E. Brownlee, an astronomer and astrobiologist, both faculty members at the University of Washington.An alternative view point was argued by Carl Sagan and Frank Drake, among others. It holds that Earth is a typical rocky planet in a typical planetary system, located in a non-exceptional region of a common barred-spiral galaxy. Given the principle of mediocrity (also called the Copernican principle), it is probable that the universe teems with complex life. Ward and Brownlee argue to the contrary: that planets, planetary systems, and galactic regions that are as friendly to complex life as are the Earth, the Solar System, and our region of the Milky Way are very rare.
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