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.
Undergrad How Can I Predict When Venus Will Be Visible as an Evening or Morning Star?
  • Cantstandit
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Graduate Surface gravity as a function of luminosity?
  • Mr. Bond
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Graduate Why Does NGC 7603's Bridge Defy Redshift Expectations?
  • SeventhSigma
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Undergrad Does outer space just have two spatial dimensions.
  • Dremmer
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Graduate How Do Scientists Use Zircons to Date the Earth's Formation?
  • Wallis
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Undergrad Phenomenon of rotation of planets
  • dpa
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Graduate Is There Such a Thing as Dark Time?
  • geelsu
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Graduate How can I recognize H alpha line?
  • 19matthew89
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Undergrad Energy Density of a magnetic field
  • Macarenses
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Graduate How does CMB support the predictions of inflation ?
  • lalbatros
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Graduate Question about a torodial universe
  • Vorde
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High School Venus: Looking for Life Beyond Earth
  • Vinni
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Graduate Flatness-infiniteness logical problem
  • supermarina
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Graduate Critical density and observable mass
  • jimjohnson
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Graduate What would happen to black holes if Lambda increased?
  • marcus
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Undergrad Expansion and Contraction of Universe
  • vinayjain
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Undergrad Space Freighters: Can Containers Take Off & Land Themselves?
  • Kitchengoblin
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Graduate Recycling of gas and other materials in galaxies
  • H2Bro
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Graduate The Properties of Jupiter's Core that give it magnetism?
  • electron_man
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Graduate Can Scientists Locate the Center of the Universe?
  • nihilius
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Graduate Liberate all the matter from a black hole
  • ugalpha
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Graduate What is the concept of mass splitting?
  • PCSL
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Graduate A thought experiment regarding the nature of space expansion
  • salvestrom
  • · Replies 30 ·
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Graduate Is space-time flat or curved over time?
  • Gill tunnel
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Undergrad Why Are Giant Stars So Low in Density?
  • triabva2003
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Undergrad Goldilocks Zone: A Widened Definition
  • Nigle Amar
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Graduate Singularity, Infinity, Edge, Expansion
  • Flustered
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High School Do Solar Flares Increase Sunburn Risk?
  • tf22raptor
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High School Layman's question on Cosmic Microwave Background
  • FalkonJenova
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Graduate Why are spiral galaxies generally planar?
  • newtonsdad
  • · Replies 10 ·
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Graduate Does Dark Matter Really Exist? A Look at Alternative Theories in Astrophysics
  • Swankie
  • · Replies 28 ·
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Graduate Fridman's Equation: Understanding Lambda, K, and the Hubble Parameter
  • supermarina
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Graduate How does the tilt and orbit of a planet affect its analemma shape?
  • Swankie
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The Universe - infinite or not ?
  • drag
  • · Replies 139 ·
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Undergrad Can Spider Silk Be Used As Space Tethers?
  • geordief
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Graduate 'A Universe From Nothing' by Lawrence Krauss, AAI 2009
  • Schlofster
  • · Replies 63 ·
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High School Gravity & Universe: Is Everything Falling?
  • cottonkat5
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Graduate Tidal lock due to rotation of displaced mass
  • Dmstifik8ion
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Undergrad Astrometeorology: A real science?
  • LightbulbSun
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Graduate Why Don't Distant Objects Fade to Black?
  • mnb96
  • · Replies 22 ·
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High School Pulsars: fluctuating speed of rotation?
  • likewhaaa
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Undergrad Expanding Universe: What We See & How We Know
  • Swimfit
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Graduate What is the basis for the theory that WIMPs could be detected by
  • sahmgeek
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Undergrad Are Black Holes Real Holes or Just Theoretical Constructs?
  • eirhnh
  • · Replies 23 ·
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Undergrad Questions concerning hypervelocity stars
  • Travito
  • · Replies 9 ·
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Stargazing Any tips for amateur astrophotography beginners?
  • Adyssa
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High School Oxygen, and space what are the effects?
  • DubaUe
  • · Replies 16 ·
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Graduate Dark Matter, Dark Energy, Dark Flow ohh
  • rhody
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High School What is the size of the universe
  • jbander
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Graduate Can expansion be due to large-scale curvature?
  • claycravens
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Graduate How Do Eclipses Affect the B-V Index of Identical Binary Stars?
  • Fernsanz
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High School Proxima Centauri closest star. super nova
  • budd
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Graduate Loss of obliquity on mars and its consequences toward life
  • Nano-Passion
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Undergrad Calculating the period of an orbit
  • solarblast
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Undergrad Discovering the Universe's Flatness: Insights from an Amateur Astronomer
  • CCosmin
  • · Replies 13 ·
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Stargazing Your Thoughts on a High Altitude Telescope
  • Drakkith
  • · Replies 19 ·
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Graduate Black hole complementarity and omnipresence
  • skydivephil
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Graduate Fermions in Early Universe: Why We Ignore Them?
  • Accidently
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Undergrad Universe radius 1,000 years ago?
  • termina
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Undergrad Calculating Energy of Separating Stars: Potential vs Kinetic Energy
  • zezima1
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Graduate Into what dimension is Spacetime Curved?
  • PhanthomJay
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High School Can Planets Revolve Without Rotating and What Determines Their Direction?
  • revelation101
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Graduate Neutrinos & Gravity: Faster than Light?
  • keepitmoving
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High School Possible Explanation for Red Flickering of Betelgeuse Star in the Night Sky
  • Johnahh
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Graduate Visualizing Alfven Waves in a Spherical Galaxy
  • sparkle123
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Graduate Does a black hole really have mass?
  • Jimmy9
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Graduate Orbital Elements-Identification of method
  • solarblast
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Undergrad Expanding Universe-Colliding Galaxies?
  • Jimmy9
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Graduate Is there an absolute motionless?
  • evangoor
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Graduate Scanning pattern in Planck's maps
  • zonde
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High School Do stars actually collide in galactic collisions?
  • bostonnew
  • · Replies 16 ·
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Graduate Inflation and accelerated expansion of the universe
  • alvarogz
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Graduate Spacetime expansion effects on wavelength of travelling light
  • H2Bro
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Graduate How Long to Ingest an Earth-Size Planet?
  • wolram
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Undergrad Gravity and space curvature confusion
  • ax53
  • · Replies 10 ·
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Graduate Quantum entanglement and black holes
  • bled_eidol
  • · Replies 16 ·
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Graduate Planetary Systems within Elliptical Binary Stars?
  • MrMojo1
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Graduate What do the processes of first, second and third dredge-up do with a
  • eXorikos
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Cannot see the milky way in dublin?
  • gttjohn
  • · Replies 15 ·
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Graduate Difference between blast & shock wave
  • Jain_Mor
  • · Replies 5 ·
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High School Time Earth reached its Perihelion
  • Philosophaie
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Graduate Is There Experimental Proof of Dark Energy and Antigravity?
  • revelation101
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Graduate Supernova explosion near a black hole
  • vinayjain
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Stargazing New Celestron CPC 925 XLT Telescope Arrives - Dave's Story
  • davenn
  • · Replies 7 ·
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Graduate Ultimate fate of the universe via a Bose-Einstein condensate
  • Dale79J
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Stargazing Go with the Orion Skyview pro 120mm refractor
  • BreMatthews
  • · Replies 3 ·
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Graduate Why Is the Universe Non-Uniform Despite Uniform Physical Laws?
  • thedragonbook
  • · Replies 44 ·
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Graduate The source of cosmic background radiation
  • Lesnick
  • · Replies 5 ·
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Graduate If the universe is truly expanding, why aren't any stars getting dimmer?
  • dcorbett
  • · Replies 9 ·
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Graduate Deflection of light passing close to the sun
  • Lesnick
  • · Replies 5 ·
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High School Milky Way's Supermassive Black Hole to Light Up in 2013?
  • chemisttree
  • · Replies 9 ·
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A question with a purpose for other thoughts.
  • DubaUe
  • · Replies 1 ·
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Where Did the Mysterious Metal Balls Falling from Space Come From?
  • surajt88
  • · Replies 8 ·
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Graduate Stephen Hawking says there is no God. But,
  • William Tu
  • · Replies 33 ·
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Graduate What time of year observations of crab pulsar were made
  • SUDOnym
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Graduate Cosmological vs Doppler redshift
  • moving finger
  • · Replies 14 ·
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Undergrad Orbit to the Moon: nodes position
  • andreajf89
  • · Replies 8 ·
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Graduate How Do the Schechter Function and Maximum Likelihood Method Differ?
  • jl294
  • · Replies 3 ·
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Graduate Evidence that black holes gain in mass?
  • Kael42
  • · Replies 16 ·
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Undergrad How Long Do Red Giant Stars Last?
  • robertrej
  • · Replies 3 ·
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