Astronomy, Astrophysics, Cosmology Forum

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Join in expert discussion on the topics of Astronomy, astrophysics and cosmology. This may include discussion on celestial objects, space, and the physical universe as a whole. Mainstream science only.
High School Is the earth the centre of the solar system?
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Graduate Island universe eventually true?
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Graduate Does a black hole have a temperature profile?
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Graduate Universal Expansion: Is Gravity Limited?
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Graduate WMAP cold spot and void in the universe
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Where to Find Free Astrophysics Books Online?
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Graduate What's the fastest space pulls apart from itself?
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What is the Intriguing Theory of Null Physics?
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High School Why do the sun and moon look bigger when rising and setting?
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Graduate Applying the Virial Theorem to Stellar winds
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Graduate How Do Astrophysicists Measure Solar Mass Loss?
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High School Understanding Spectral Index: A Plain Explanation
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Undergrad Artificial Gravity: Sci-Fi Possibility & Effects
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Graduate Evidence for the Inflationary Period?
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Graduate Does the Cosmic Background Radiation Provide an Absolute Frame of Reference?
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Graduate Why Isn't Dark Energy Considered a Fundamental Force?
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Graduate Logical Positivism versus Cosmology
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Graduate Gravitationally bound, ionized cloud of hydrogen
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Graduate Cauchy horizon in a Kerr rotating black hole
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Undergrad Viewing size of Galaxies 7 Billion light years away?
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Graduate Hardness of Neutronium: Estimating Magnitude
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Graduate Ray of light travelling through universe (applying cosmological principle)
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Graduate Is the Accelerating Expansion of the Universe Caused by Energy Conversion?
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Undergrad Calculating Fuel Needed for Geosynchronous Orbit
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Graduate Baryon Asymmetry: Why is Matter More Abundant?
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High School How Long Does it Take the Moon to Orbit the Earth?
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Graduate Is the concept of a creator necessary if the universe has always existed?
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Undergrad Early Warning against Killer -Asteroids - current state, ideas
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Graduate Void expansion rate and cosmic acceleration.
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Undergrad What is the Significance of a Secular Timescale?
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Graduate Will dark energy overcome dark matter?
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Graduate Dark Matter Detection: Earth's Orbit and Its Interactions with the Solar System
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Graduate Question regarding about Ωbaryonic/DM/DE
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Graduate Is There Really No Edge to Space, Only an Edge to Time?
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Graduate Congratulations to all the PF gurus
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Graduate A Theory on the possible fate of the universe
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Graduate Black holes, frame dragging and the effect on gravity
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Graduate What would happen to time if all movement were parallel?
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Apophis Strikes Earth: Odds still 1 in 45,000
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Undergrad How to find data on Earth, planets, motions
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Graduate What Are the Different Horizons and Distance Scales in Cosmology?
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Undergrad Is the Root 2 Relationship Valid for Orbital Mechanics on the Moon?
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Undergrad Hubble's Discovery of Cepheid Variable Stars in Galaxies
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Undergrad How Do Scientists Measure Distance Using Standard Candles?
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Graduate The Rotation of the Universe: A New Perspective on Cosmic Expansion
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Undergrad Ratio between Semi major and Velocity
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Undergrad Rotational Motion of Celestial Body
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Undergrad Apophis to impact earth in 2036?
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Graduate The Void Phenomenon Explained (Tinker Conroy, computer sims)
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Graduate I Know Why We Will Never Come Across A Wormhole
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Graduate What Happens to Time and Space at the Event Horizon of a Black Hole?
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Graduate Loeb's perspective on emergence of structure
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Graduate Do Laws of Physics Break Beyond the Event Horizon in Kerr Black Holes?
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Undergrad Torque caused by/due to a galaxy's spin
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Graduate How Does Hubble's Constant Relate to Universe Inflation and Horizon Changes?
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Graduate Inflation & the Speed of Light: Is It Possible?
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Graduate What Happens to Infalling Matter as a Black Hole Evaporates?
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High School What Causes Multi-Colored Stars to Twinkle in the Night Sky?
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Graduate Synchronous Moon Stability: Conditions & Twin Planet Distance
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Undergrad Will a Toy Top Keep Spinning in Space?
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Undergrad Orbiting space station is observed to remain always vertically above
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Graduate Wien's Law & Earth Emission Spectra: Investigating the discrepancy
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Stargazing Telescope alteration (Russ or turbo-1)
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Undergrad Will voyager 1 or 2 pass the heliopause
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Graduate Gravitational attraction of bodies
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Graduate So you discover the dark matter particle Now what?
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Graduate Is expansion only a factor in empty space?
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Graduate Artificial Stars: Dream or Possibility?
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Graduate Light-Years, Horizons & the Age of the Universe
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Graduate Are TOEs Ignoring the Complexity of Animate Matter?
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High School Are Cosmic Rays Just Electromagnetic Rays from Space?
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Graduate Faster than light expansion speeds are standard
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Undergrad Big Bang & Universal Speed Limit: Is Light the Limit?
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Graduate Stability of cosmological models
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High School The Earth and its orbit around the sun
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Graduate Why do we say black holes vanish if their mass decreases with hawking radiation?
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Graduate The Pre-Big Bang Universe: The Origin of Matter and Energy from the Vacuum
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Graduate Curvature of space; curvaure of spacetime
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Undergrad The Big Bang, and where it occured in space.
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Graduate Universe expanded faster than the speed of light?
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Graduate Start from Nothing: An Exploration of Pre BB Thinking
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Graduate Predicting Universe Collapse: Understanding the Forces at Work
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Graduate The End of Cosmology: Is Special Relativity at Odds?
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Where Can I Download M.V.Berry's 'Stability of the Solar System' Paper for Free?
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Graduate How fast does the universe expand and what are the theories behind it?
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Undergrad What is Dark Energy and How Does It Affect the Universe's Expansion?
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High School Are those shooting stars or satellites in the night sky?
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Online Discussion: The End of the World in 2012?
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Graduate Boltzmann Brains: NY Times Article Explained
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Graduate Shape of Black Holes: Clarification Needed
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Graduate Queston On The Theory Of Everything
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Graduate Negative Acceleration in Black Holes
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Graduate The fuzzball proposal for black holes
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Graduate Visualizations without space-time or light
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Graduate Angular momentum of an oblate spheroid
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Graduate Hawking radiation & Information loss
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Graduate Beckenstein Bound: Understanding Smolin's Entropy Bounds
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High School A question about the evidence for the age of our known universe
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Graduate Has anyone rebutted E. Lester Smith's Intelligence Came First theory?
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Graduate At the April APS meeting: curing cosmic singularities
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