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.
Threads
High School Was there more than one Big Bang?
- Krasimir
- · Replies 9 ·
High School Are Quasars Still Present in Our Universe?
- Richard87
- · Replies 3 ·
Graduate How Does the Integrated Sachs-Wolfe Effect Support the Concept of Dark Energy?
- cbd1
- · Replies 4 ·
Graduate Finding distance to a second Cephid variable given magnitude difference
- Unto
- · Replies 4 ·
Graduate What Would an Infinite Universe Look Like at the Time of the Big Bang?
- Backwoods
- · Replies 6 ·
Graduate Could quantum effects prevent gravitational collapse to a singularity?
- Chimps
- · Replies 44 ·
High School How do I calculate light years to years?
- Kronos5253
- · Replies 5 ·
Undergrad Transmission Bandwith though space
- DarkStar707
- · Replies 5 ·
Graduate How can causality start the Big Bang if time doesn't exist yet?
- zeromodz
- · Replies 16 ·
Graduate Pauli Exclusion Principle: Finite Creativity or Philosophy?
- yannick^
- · Replies 1 ·
Graduate Does cosmic expansion contradict momentum conservation in a closed universe?
- iidartzii
- · Replies 1 ·
Undergrad Trying to find out how exactly we find out how big the visible universe is.
- zeromodz
- · Replies 2 ·
Possible dark matter discovery announced
- DARKSYDE
- · Replies 1 ·
Stargazing A simple refractor homemade telescope
- Peter
- · Replies 6 ·
Undergrad Are AGNs or GRBs a greater danger for life on Earth?
- Maitreya
- · Replies 4 ·
Graduate Black holes, white holes and expansion of Universe
- Skolon
- · Replies 7 ·
Graduate Super-earth transiting nearby star
- marcus
- · Replies 1 ·
Undergrad What Can the Gravitational Binding Energy Equation Tell Us?
- Stratosphere
- · Replies 1 ·
Undergrad Is there cyclic motion of galaxies?
- lazypast
- · Replies 7 ·
High School Are the planets where we expect them to be
- Bjarne
- · Replies 6 ·
Graduate Is the third spatial dimension an illusion from rapid 2D frames?
- evanghellidis
- · Replies 7 ·
High School How do spaceships move in space without any propulsion source?
- MotoH
- · Replies 8 ·
Undergrad Physics for a science fiction book with realistic spaceship propulsion
- NeomerArcana
- · Replies 15 ·
High School Can We Send a Probe to Proxima Centauri?
- Richard87
- · Replies 3 ·
Graduate Proximity of early galaxies to each other
- dilletante
- · Replies 2 ·
Undergrad Is the sun at the focus of parabolic and hyperbolic trajectories?
- IPhO' 2008
- · Replies 3 ·
Graduate Does the expansion rate of our universe depend on its mean density?
- MathematicalPhysicist
- · Replies 17 ·
Undergrad What makes gravity work and what are its components?
- Maelstrom
- · Replies 2 ·
Graduate Horizon problem - why do we need inflation?
- Dmitry67
- · Replies 41 ·
Graduate What is the Latest Exoplanet Catalog from Geoff Marcy and Paul Butler?
- marcus
- · Replies 29 ·
Graduate What is GJ 1214 b: A Super-Earth Water World Orbiting a Red Dwarf Star?
- Orion1
- · Replies 1 ·
High School Big Bang Theory: Fact or Fiction?
- Codester09
- · Replies 4 ·
Undergrad Why doesn't radiation energy create enough gravity to explain galaxy rotation?
- VooDooX
- · Replies 31 ·
Undergrad Does the sun have angular momentum?
- mikeph
- · Replies 14 ·
Graduate Rotation Curves and the Influence of Stellar Mass on Orbital Velocity
- frankinstein
- · Replies 21 ·
Graduate What is our universe expanding into?
- Robert100
- · Replies 37 ·
Undergrad Find Apparent Magnitude of Binary Star System w/o Distance
- vivekdoulat
- · Replies 1 ·
Huge comet seen on soho web page.
- freethsone
- · Replies 14 ·
Undergrad What are the Sun's galactic coordinates?
- zero.kalvin
- · Replies 13 ·
Graduate Can Modified Gravity Explain Cosmic Structure Without Dark Matter?
- SF
- · Replies 11 ·
Graduate Correcting Galaxy Luminosities for Absorption ?
- Widdekind
- · Replies 2 ·
Tabulation of the Standard Astronomical Filters
- natski
- · Replies 1 ·
Undergrad Understanding Units of dex^-1 in Number Density Measurements
- v0lD
- · Replies 3 ·
Undergrad Liquid water on Venus in early history.
- Richard87
- · Replies 2 ·
Graduate Did the universe's escape velocity drop below light speed as it expanded?
- edpell
- · Replies 6 ·
Undergrad Short existence of liquid water on Mars (explanation related to thin atmosphere)
- ajassat
- · Replies 7 ·
Graduate Is Modified Gravity Theory a Viable Alternative to Dark Matter?
- MonstersFromTheId
- · Replies 36 ·
Graduate How do we know that spacetime is expanding
- Gerinski
- · Replies 2 ·
Graduate Strange hexagonal shape on Saturn's north pole.
- The_Absolute
- · Replies 2 ·
Free, downloadable solar system simluation.
- PrincePhoenix
- · Replies 1 ·
Graduate Different equations for the virial theorem in astrophysics
- Stratosphere
- · Replies 1 ·
Is the Higgs Particle Just a Myth?
- emc2cracker
- · Replies 3 ·
Undergrad Deriving the elliptical orbit equation with eccentricity
- skiz
- · Replies 7 ·
Graduate Future of the universe without proton decay.
- Richard87
- · Replies 2 ·
Graduate Can Modifications to Gravity Explain the Accelerating Expansion of the Universe?
- inflector
- · Replies 9 ·
Finding the Best University for 16-Year-Old in Greece
- Dimosthenis
- · Replies 4 ·
Graduate What is the newly discovered explanation for the evolution of spiral galaxies?
- Charles Franc
- · Replies 8 ·
Undergrad Orbital energy of ellipse and hyperbolic trajectory
- IPhO' 2008
- · Replies 2 ·
Cause of the 2009 Norwegian spiral UFO phenomenon
- pixel01
- · Replies 4 ·
Graduate Derivation of velocity dispersion from virial theorem?
- taylrl3
- · Replies 1 ·
What Lies Beyond the Universe?
- Louis Wu
- · Replies 4 ·
Astronomy or Cosmology Christmas gift ideas
- Ivan Seeking
- · Replies 9 ·
Graduate Ted Bunn on expansion, redshifts and the dangers of 'rubber sheets'
- Wallace
- · Replies 7 ·
High School How many arcseconds does Sun travel through sky?
- MarkB7
- · Replies 15 ·
Graduate What is the relationship between stars, lithium, and exoplanets?
- Arch2008
- · Replies 3 ·
High School Finite Black Holes? Answers for Xap's Question
- Xaphan
- · Replies 7 ·
Undergrad Why Can't Rocky Planets Exceed 14 Times Earth's Size?
- Silverbackman
- · Replies 25 ·
Undergrad CFD in Astrophysics, ideas for a senior project
- simo.alb88
- · Replies 4 ·
Graduate Why do sources claim a 20-minute difference between tropical and sidereal years?
- MarkB7
- · Replies 18 ·
Graduate Redshift and Particle Momentum Decay
- Jorrie
- · Replies 10 ·
Virgin Galactic's SpaceShipTwo commercial spaceship
- mgb_phys
- · Replies 48 ·
Graduate Is the Steinhardt-Turok Cyclic Model Gaining Support?
- Descartz2000
- · Replies 3 ·
High School Improbable conditions that allowed life to evolve on Earth
- Grozny
- · Replies 17 ·
Stargazing Choosing a telescope for amateur astronomy on a $250-500 budget
- Codester09
- · Replies 11 ·
Undergrad Accelerating Expansion Threshhold
- tfb
- · Replies 37 ·
High School Can the sun be blueshifted due to Earth's rotation?
- GetPhysical
- · Replies 19 ·
Graduate Is the universe an open or a closed system?
- Topher925
- · Replies 8 ·
High School Was the Big Bang theory proven wrong?
- The_Z_Factor
- · Replies 24 ·
High School Uranus' satellite Miranda question
- Echo 6 Sierra
- · Replies 2 ·
Undergrad Stars born in clusters, found in single
- dotancohen
- · Replies 10 ·
Graduate What Is the Fundamental Relationship Between Space and Matter?
- Protez
- · Replies 4 ·
Undergrad What Would Happen if Two Black Holes Got Too Close?
- Ultrastar 1
- · Replies 10 ·
Undergrad Answer "What Does C=Vλ Mean? Find Energy of Photon
- zeromodz
- · Replies 6 ·
Undergrad Evidence of Expansion: Redshifting of EM Radiation
- Calimero
- · Replies 3 ·
Graduate Antimatter (in relation to earth)
- Nanak
- · Replies 2 ·
High School Is there evidence to support past life on Mars?
- Richard87
- · Replies 30 ·
Graduate Why do stars orbit around a spiral galaxy in a rosette shape?
- Master J
- · Replies 3 ·
Graduate Supergalactic cluster waves and geological cycles
- RayTomes
- · Replies 44 ·
Undergrad Energy required to the Moons orbit
- Bjarne
- · Replies 9 ·
Undergrad When Will the Sun Transition to a Black Dwarf?
- Richard87
- · Replies 3 ·
Graduate What is Hilbert space?
- ZaiKin786
- · Replies 9 ·
Undergrad Can Supermassive Black Holes Really Exist and What Evidence Supports Them?
- Ultrastar 1
- · Replies 12 ·
Graduate Does recent expansion change the predicted CMB temperature?
- BillSaltLake
- · Replies 14 ·
Graduate Hey guys, this is my theory of blackholes and how new parallel universes
- aidantrembath
- · Replies 3 ·
Where can I listen to radio waves from space and planets?
- radio_wav
- · Replies 3 ·
Graduate Can white holes really exist as the opposite of black holes?
- Moloch11
- · Replies 5 ·
Undergrad Are Distant Galaxies Moving Faster Than Light?
- mdnazmulh
- · Replies 9 ·
High School Where is the center of the universe in relation to the Big Bang?
- Blakesterc8
- · Replies 14 ·
Undergrad Are Distant Galaxies Composed of Matter or Anti-Matter?
- AaronKnight
- · Replies 12 ·
High School How far would the moon need to be to lose gravitational effect on Earth?
- GuitarGirl
- · Replies 7 ·