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
Graduate Is the Universe spinning on a vast scale?
- Orion1
- · Replies 24 ·
High School Why are there 12 months in a year instead of 365?
- Phy_enthusiast
- · Replies 21 ·
High School Does Earth's gravity on the Moon exceed the Sun's gravity on the Moon?
- sirwan
- · Replies 11 ·
Graduate Simulating the Apophis encounter on April 13, 2029
- Jano L.
- · Replies 11 ·
Graduate What exactly is a quasar and how does it relate to black holes?
- jaydnul
- · Replies 11 ·
Graduate Is the Big Bang a theory or a hypothesis?
- TheDestroyer
- · Replies 8 ·
Graduate How can an infinite universe be expanding?
- Ben.meyer
- · Replies 3 ·
Undergrad Binary star revolving arround center of mass
- point ohms
- · Replies 2 ·
Undergrad What is the heliotail and how was it discovered by IBEX spacecraft?
- Dotini
- · Replies 4 ·
High School Black Hole Destination: Final Stages, Next Steps, Reasons
- point ohms
- · Replies 1 ·
Undergrad Mass/Energy Creation and Conservation
- Nugso
- · Replies 8 ·
Graduate Nature of Primodial Existance before bigbang
- tlnarasimham
- · Replies 4 ·
Undergrad How direction of satellite changes
- lalu
- · Replies 3 ·
Graduate Calculation of Neutron star pressure/mass using 4th order Runge-Kutta
- mary1986
- · Replies 3 ·
Undergrad Tidally locked planet's sun still moves?
- Algr
- · Replies 14 ·
Graduate Could a collapsing black hole explain the big bang and CMB?
- aaron_ironmon
- · Replies 6 ·
Undergrad How do you find the distance to the galaxies having equal diameter?
- iVenky
- · Replies 8 ·
Graduate Relative Motion of Planet to Star: Gm1m2/r^3 - Gm1m2/r^3 = 0
- Jadaav
- · Replies 4 ·
Graduate Does Parabolic Motion Follow Kepler's Second Law?
- DuncanM
- · Replies 6 ·
High School The solar system 90 degrees to milky way
- jeritude
- · Replies 8 ·
Graduate How Does Entropy Change as the Universe Evolves?
- m_robertson
- · Replies 7 ·
High School What is Big Bang? Why did it take place?
- AkshayD
- · Replies 2 ·
Graduate Spatial scale in inverse Fourier transform from k-space to object space
- jasonpatel
- · Replies 7 ·
Stargazing Hubble telescope finds a planet where it rains glass
- Greg Bernhardt
- · Replies 3 ·
Missing the Aurora Australis from Sydney
- davenn
- · Replies 2 ·
Graduate The 'Huge-LQG' quasar 'structure' does not violate homogeneity
- Sesh
- · Replies 3 ·
Undergrad Mass of orbiting body calculations
- gtsinc
- · Replies 8 ·
High School Why Does a Hole in Paper Show an Eclipse Shadow?
- adjacent
- · Replies 5 ·
Cosmos like book/documentary/movie
- Nugso
- · Replies 15 ·
Celebration of eid ul fitr in east
- cooper607
- · Replies 2 ·
Undergrad Can the earth loose its orbit and regain its orbit again
- kryptoner
- · Replies 2 ·
Graduate The cosmological Big Rip and a shrinking hubble radius
- fet2105
- · Replies 10 ·
Graduate How Do Electromagnetic Waves Interact with Living Organisms?
- vinzie
- · Replies 1 ·
High School What Happens to Living Things That Enter a Black Hole?
- Sudip Pradhan
- · Replies 5 ·
High School Stellar or Solar system Astronomy?
- Jokmal
- · Replies 2 ·
Optics Question: How do I clean polar sheets?
- piareround
- · Replies 2 ·
Graduate Is The Big Bang still a Black Hole.
- Baluncore
- · Replies 11 ·
Graduate Why does redshift necessarily imply cosmological expansion?
- MishaFreeman
- · Replies 13 ·
Graduate Something I Don't Understand about Black Hole density.
- AndromedaRXJ
- · Replies 25 ·
Undergrad Does the universe have boundaries?
- Arifz
- · Replies 118 ·
Supermoon: Closest of 2013 on June 22-23
- Sudip Pradhan
- · Replies 1 ·
Graduate Paper: Constraints on Dark Matter in the Solar System
- inflector
- · Replies 7 ·
Graduate Spacetime expanding at a rate equal to the speed of light
- fet2105
- · Replies 3 ·
Graduate Are Nesting Universes Possible and How Does Gravity Fit In?
- RickBman
- · Replies 6 ·
Graduate Gravitation as curvature of space vs field theory
- rudolfbaer
- · Replies 6 ·
Undergrad Center of the galaxy and the great attractor
- WavesOfPhysics
- · Replies 6 ·
Undergrad What evidence supports the big bang theory?
- question dude
- · Replies 10 ·
Graduate Is the Hubble Radius the Actual Radius of Our Universe?
- johne1618
- · Replies 12 ·
High School Is what I saw - a meteor that was heading in my direction?
- Disgusting spy
- · Replies 6 ·
Graduate Book recommendations on C, P and T symmetry violation in the early universe
- MrNeu
- · Replies 2 ·
Graduate What is the maximum recessive velocity of a galaxy in the observable universe?
- EskWIRED
- · Replies 5 ·
Graduate Effects of a vacuum/ the expansion of the universe is accelerating
- stepson
- · Replies 4 ·
Graduate How can black holes have magnetic poles and jets if nothing escapes the event horizon?
- RickBman
- · Replies 1 ·
Graduate Early Universe scalar field, inflaton and analogies in electric field
- say_cheese
- · Replies 4 ·
Graduate Length of ruler in expanding Universe
- johne1618
- · Replies 30 ·
Stargazing Reflection losses at air-glass interfaces in refracting telescopes
- mrspeedybob
- · Replies 2 ·
Undergrad What does it mean for the universe to be geometrically flat?
- MathJakob
- · Replies 8 ·
Graduate Quantum entanglement to communicate from inside black holes
- yoplait
- · Replies 9 ·
Undergrad Why is Hubble's constant called a constant if it changes?
- MathJakob
- · Replies 8 ·
Graduate Acceleration/deceleration of the expanding universe?
- PeterZimmerman
- · Replies 3 ·
Graduate Ladies and Gentlemen Voyager 1 Has Left the Solar System
- BadBrain
- · Replies 42 ·
Graduate Loop quantum cosmology predicting 145 e-folds of inflation
- marcus
- · Replies 15 ·
Stargazing FOV for galilean vs keplerian telescope
- fsonnichsen
- · Replies 6 ·
Graduate Which universities in Australia offer a PhD in Astronomy?
- subny
- · Replies 2 ·
Graduate Force of Gravity Just Prior to the Big Bang
- plerza
- · Replies 14 ·
Graduate Philosophy of cosmology as a new academic field
- Clayjay
- · Replies 10 ·
Graduate Supernova Dimming and Angular Distance Diameter
- titowakoru
- · Replies 2 ·
Graduate Giant Collision, the Jupiter in the Recent Past
- shivaj15
- · Replies 5 ·
Graduate An infinite universe can expand?
- MathJakob
- · Replies 5 ·
Stargazing What Kind of Paint Is Used for Radio Telescopes?
- mishima
- · Replies 8 ·
Undergrad How Does Object Collision Work in Space?
- OneCookie
- · Replies 3 ·
Undergrad Is density of a material affected by gravity? If so
- liubare
- · Replies 3 ·
High School Does Newton's Law of Gravitation Apply in Outer Space?
- arunborah
- · Replies 4 ·
Graduate Three privileged directions in the universe
- exponent137
- · Replies 10 ·
Graduate Dark matter and dark energy as a relativistic mass?
- petergreen
- · Replies 3 ·
Undergrad Why is the Moon's Gravity Uneven?
- BIT1749
- · Replies 3 ·
Graduate Black holes, Creating Black holes
- omiros
- · Replies 1 ·
Graduate Is time and space truly symmetric in light of Noether's theorem?
- JayJohn85
- · Replies 5 ·
Graduate A couple of questions about The Big Bang Theory
- bpl1227
- · Replies 13 ·
Graduate The vicious circle of standard redshift explanations
- glengarry
- · Replies 22 ·
Graduate Gravitational center of the Local SuperCluster
- mateuszica
- · Replies 11 ·
Graduate What happens to heavy atoms that come into the atmosphere as cosmic
- nealshireman
- · Replies 4 ·
Graduate Dark matter to radiation density ratio on page 190 of Dodelson
- alejandrito29
- · Replies 6 ·
Graduate Gravitational Capture: How Can Binary Stars Form?
- Jarwulf
- · Replies 1 ·
High School Sun moves north as it sets in wunderground video
- KenJackson
- · Replies 1 ·
High School Why do hurricanes and spiral galaxies look so similar?
- astroscout
- · Replies 6 ·
Undergrad Confusion about the accelerating expansion of the universe and Hubble
- question dude
- · Replies 6 ·
Graduate Is Light Speed Consistent in Conformal Time?
- johne1618
- · Replies 1 ·
Graduate Is there a time paradox in Big Bang cosmology?
- glengarry
- · Replies 12 ·
High School Would spinning the Moon affect tides and life on Earth?
- mallaky
- · Replies 3 ·
Graduate How can a universe come from nothing?
- mattattack
- · Replies 14 ·
Graduate Hippacros star catalogue - astrometric calculations
- Sword7
- · Replies 3 ·
Undergrad Did a Giant Impact Start the Moon's Movement?
- wing43
- · Replies 4 ·
High School Can we detect black holes by any means other than light?
- bhpv
- · Replies 6 ·
Graduate Did the early universe plasma stay plasma for 380,000 years?
- Kylie87
- · Replies 5 ·
High School Was the Bright Ball with Blue Light I Saw Through My Binoculars Saturn?
- chemistry1
- · Replies 8 ·
Graduate What Was the Speed of Light During Cosmic Inflation?
- Gerinski
- · Replies 29 ·
Graduate What Are Acoustic Waves and 7 Peaks in CMB Anisotropy?
- Madster
- · Replies 2 ·
Undergrad Delta V as a Function of Altitude
- a0077277
- · Replies 5 ·
Graduate Are small extra space-time dimensions represented correctly?
- bpmirsch
- · Replies 5 ·