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 Determine whether A is orbiting B
- h4tt3n
- · Replies 2 ·
Undergrad Amount of energy inside a sphere of radius 1au around the Sun
- confusedhome
- · Replies 14 ·
Stargazing Event Horizon Telescope Results Released Yesterday (April 10, 2019)
- mfb
- · Replies 129 ·
High School Particle Deceleration in Relativistic Jets?
- metastable
- · Replies 58 ·
High School How do we know that the Universe is expanding?
- MikeeMiracle
- · Replies 16 ·
High School What process allows us to 'see' lightyears of distance with the natural eye?
- Surayabay
- · Replies 53 ·
Undergrad Does the gravity sling require rocket guidance to be non-negligible?
- Jonathan212
- · Replies 5 ·
Undergrad How was the Earth's Orbit Derived?
- mdeng
- · Replies 1 ·
Graduate How Does Rotational Velocity Affect Gravity and Space Launches?
- Taremos
- · Replies 1 ·
High School Does antimatter repel gravity and cause cosmic expansion?
- questionator89
- · Replies 3 ·
High School Can someone please explain this paragraph from A Brief History Of Time
- Rishabh Narula
- · Replies 6 ·
Undergrad SpaceX's 5K Satellites: A Risk of Man-Made Meteors?
- swampwiz
- · Replies 2 ·
Undergrad My 3rd question - About Stellar Spectrum
- ThomasJoe40
- · Replies 2 ·
High School What’s more “important": GR or QM?
- SJay16
- · Replies 7 ·
Undergrad What Justifies the Slight Preponderance of Matter Over Anti-Matter?
- adrianxw
- · Replies 25 ·
Stargazing Does Our Picture of the Universe Become Less Accurate the Farther We Look?
- Victor Lee
- · Replies 4 ·
Undergrad How is dark matter thought to have formed a network scaffolding?
- hkyriazi
- · Replies 40 ·
High School Can a sun have a moon?
- Ralph Rotten
- · Replies 27 ·
Undergrad Does the universe have a definite "size"?
- ScottVal
- · Replies 5 ·
High School Expansion or contraction -- how do we know which?
- Greenlight
- · Replies 24 ·
Undergrad BREAKING: New potentially habitable exoplanet found around Teegarden
- alberto91
- · Replies 1 ·
Undergrad Equation of state and density parameter
- Ranku
- · Replies 6 ·
Undergrad Cosmological constant and structure formation
- Ranku
- · Replies 3 ·
High School How well should Astronomers know General Relativity?
- SJay16
- · Replies 1 ·
Undergrad Spacetime curvature and curvature index
- Ranku
- · Replies 7 ·
High School What is Hubble's Luminosity Law?
- angela6884
- · Replies 2 ·
Undergrad Creation of our universe from zero energy?
- entropy1
- · Replies 8 ·
Graduate 2-body inspirals that circularize
- tempus
- · Replies 2 ·
Undergrad What's the largest rocky planet with 1g gravity in theory?
- greswd
- · Replies 15 ·
High School The Hubble deep field photos and the edge of the universe
- Sophrosyne
- · Replies 17 ·
High School Black holes and the first law of thermodynamics
- ElliotSmith
- · Replies 10 ·
High School What is the probability that the Universe is absolutely flat?
- Buzz Bloom
- · Replies 96 ·
Undergrad Coherence length of velocity fields
- Apashanka
- · Replies 5 ·
Undergrad Most-detailed-ever simulations of a BH solve long standing mystery
- Spinnor
- · Replies 5 ·
Undergrad Dark Matter not present in Galaxy when distance is Increased
- GiftOfPlasma
- · Replies 3 ·
High School Galaxy Database with distances from Earth
- Buzz Bloom
- · Replies 12 ·
Undergrad Does Hubble's law predict speeds faster than light at large distances?
- zuz
- · Replies 1 ·
Graduate Can anything capture a black hole?
- JEL
- · Replies 1 ·
Graduate Cosmological models with variable EoS
- Chronos
- · Replies 2 ·
High School Is Dark Energy Born at the Big Bang or Continually Created?
- Ken Lehn
- · Replies 2 ·
Undergrad Did Universal Physical Constants Exist at the Big Bang?
- fasteddie1371
- · Replies 2 ·
High School Is the asteroid belt horizontal or like a dome?
- Mshenko
- · Replies 7 ·
Undergrad Can Merging Black Holes Have Infinite Kinetic Energy?
- Herbascious J
- · Replies 35 ·
Undergrad Qs re Cosmological Models Using Bayesian Probability Methods
- Buzz Bloom
- · Replies 1 ·
High School Is Dark Matter a Misunderstood Global Effect?
- wolram
- · Replies 13 ·
High School Destroying asteroids shown to be very difficult
- jim mcnamara
- · Replies 50 ·
High School How would observers near a black hole measure the age of the universe?
- MikeeMiracle
- · Replies 7 ·
Undergrad The Sun's excess gamma rays and strange dips
- cube137
- · Replies 1 ·
Playing with the Universe Sandbox Software
- Ralph Rotten
- · Replies 1 ·
Graduate Does the CMB dipole indicate anisotropic expansion?
- bwana
- · Replies 5 ·
Undergrad Is the Universe a 3-sphere or a 4-sphere?
- Herbascious J
- · Replies 42 ·
High School Radio source Hercules A and galaxy 3C 348
- Nathan Warford
- · Replies 4 ·
High School New theory, our solar system formation, "space bubble"
- Spinnor
- · Replies 16 ·
High School What is empirically known about the shape and size of the Universe?
- Enquerencia
- · Replies 34 ·
What should we do with the retired Hubble?
- Phobos
- · Replies 18 ·
High School Juno -- Coolest space ship in the solar system?
- Ralph Rotten
- · Replies 3 ·
Undergrad How do radio observations of Sgr A* motion constrain its mass?
- arcTomato
- · Replies 13 ·
Insights Equations of State for Photon Gas and Relativistic Electron Gas
- andrewkirk
- · Replies 0 ·
Stargazing How Did Ancient People Calculate Celestial Measurements?
- Damned2Hell
- · Replies 7 ·
Graduate Can negative mass explain dark matter and dark energy?
- KarlM
- · Replies 131 ·
Undergrad Cosmology projects combining coding
- Arman777
- · Replies 2 ·
High School Can quantum fluctuations cancel to prevent Hawking radiation?
- Archmundada
- · Replies 3 ·
Undergrad Terraforming Mars by using Europa
- James Minwell
- · Replies 57 ·
Undergrad What physical mechanisms are involved in heating planetary bodies?
- RedGiant
- · Replies 5 ·
Undergrad Why Does Wormhole Travel Take Longer Than a 'Regular' Path?
- John Morax
- · Replies 7 ·
Undergrad Questions about the inverse square law
- KurtLudwig
- · Replies 3 ·
Undergrad How can Mars create magnetic shielding without a planetary magnetic field?
- vin300
- · Replies 14 ·
Graduate Direct Detection of Cold Dark Matter
- Garth
- · Replies 2 ·
High School Could Matter/Anti-Matter Annihilation Explain Dark Energy and Dark Matter?
- Michaela SJ
- · Replies 7 ·
High School Is the Hawking-Hartle Euclidean approach confirmed by CMBR data?
- Cerenkov
- · Replies 13 ·
Undergrad What Future Experiments Could Confirm Extra Dimensions in Cosmology?
- Tom Mcfarland
- · Replies 15 ·
High School Is 3D reality merely an illusion?
- Simple man
- · Replies 3 ·
Undergrad Can baryonic matter alone reproduce the universe's observed structure?
- Ranku
- · Replies 10 ·
High School Is the "Information Paradox" close to getting resolved?
- Simple man
- · Replies 30 ·
High School What Size Would the Universe Be if Compressed to Neutron Star Density?
- AndrzejBania
- · Replies 11 ·
Undergrad How best to photograph the Lyrid meteor shower
- Andy Resnick
- · Replies 3 ·
Undergrad Is the Floating Launch Loop a Viable Alternative for Space Exploration?
- darkdave3000
- · Replies 1 ·
Brian Cox's Adventures in Space and Time tour review coming tomorrow
- Greg Bernhardt
- · Replies 9 ·
Undergrad Planets or stars that are composed entirely out from Dark Matter.
- MathematicalPhysicist
- · Replies 4 ·
Undergrad Cosmic microwave background observations
- nmsurobert
- · Replies 3 ·
Undergrad What happens to spacetime during the expansion of the Universe?
- MikeeMiracle
- · Replies 21 ·
Undergrad So astronomers really don't have an idea about density of asteroids?
- swampwiz
- · Replies 4 ·
Undergrad What is the refractive index of the Universe?
- confusedhome
- · Replies 21 ·
Graduate Alignment of Quasar Polarizations 0507274
- CarlB
- · Replies 2 ·
Undergrad How does the expansion of the Universe affect black holes?
- Yashraj Singh
- · Replies 9 ·
Graduate How Can I Find Correction Factors for Tropical Years in Historical Data?
- jim mcnamara
- · Replies 2 ·
Graduate Analysis Paralysis: A Must-Read Paper on Cosmology Theory/Data
- Chronos
- · Replies 1 ·
Graduate Historical reprint/coverage papers requested
- Mordred
- · Replies 1 ·
Graduate Interesting video on infrared modifications to gravity
- Haelfix
- · Replies 1 ·
Graduate Observational constraints on quarks in neutron stars
- Chronos
- · Replies 1 ·
Graduate Could dark matter be composite baryonic objects?
- Garth
- · Replies 1 ·
Graduate How unitary cosmology solves the inflationary entropy problem
- DrChinese
- · Replies 1 ·
Graduate Copeland et al. review omits holographic dark energy models
- jal
- · Replies 1 ·
Graduate Black hole accretion disk/jet reference
- Mordred
- · Replies 1 ·
Graduate Lyman alpha forest different for different objects?
- Jonathan Scott
- · Replies 1 ·
Graduate Black Hole Confusion: How Karen Masters Contributed
- Chronos
- · Replies 1 ·
Graduate Recent papers on galactic evolution and metallicity
- Chronos
- · Replies 1 ·
Graduate Escape Velocity in GR - PhysicsForums
- stevebd1
- · Replies 1 ·
Graduate Does the Thermoelectric effect apply in sun?
- Spinnor
- · Replies 1 ·
Graduate Centripetal forces and gravity
- stevebd1
- · Replies 1 ·