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 event horizon of a black hole physical?
- phinds
- · Replies 70 ·
High School Can the Sagittarius and Canis Major Dwarf Galaxies be Seen with the Naked Eye?
- shounakbhatta
- · Replies 19 ·
Graduate Could a Variable Speed of Light Theory Challenge the FLRW Metric in Cosmology?
- anorlunda
- · Replies 2 ·
Graduate Are Black Holes the Ultimate Cleaners of the Universe?
- uperkurk
- · Replies 3 ·
Undergrad Could an ion engine attached to a satellite be used to stabilize orbit?
- vjk2
- · Replies 5 ·
High School Realistic space flight simulator iOS
- devGirl
- · Replies 1 ·
Graduate Primordial black holes as DM candidates
- Chronos
- · Replies 2 ·
High School Do stars rotate, and if so how is angular momentum involved?
- shounakbhatta
- · Replies 4 ·
Graduate Would Distant Galaxies Still Exist If Time Were Paused?
- jaydnul
- · Replies 9 ·
Graduate Can dark matter form planets and dark matter life?
- silvercats
- · Replies 13 ·
Graduate Back and forward orbit [around gravitating objects]
- Edi
- · Replies 52 ·
Undergrad Space Elevators -> US Transportation Infrastructure
- blu3boy
- · Replies 23 ·
Graduate Universe expansion faster than light?
- mrxyz
- · Replies 3 ·
Undergrad What would a toroidal planet be like?
- EskWIRED
- · Replies 16 ·
Undergrad Why there is so little carbon in Earth crust?
- Czcibor
- · Replies 2 ·
Graduate How can the universe exceed 14.7 billion light years if matter can't exceed light speed?
- Nabael
- · Replies 7 ·
Graduate Does the big bang explain physical or philosophical nothing?
- Jason12381
- · Replies 9 ·
Undergrad What Causes Elliptical Galaxies to be Elliptical?
- shounakbhatta
- · Replies 4 ·
Graduate Planetary Formation Based on Matter Condensation and Accretion
- PhysicsPost
- · Replies 2 ·
Undergrad Is the Universe Expanding or Has it Already Expanded?
- C. Bernard
- · Replies 96 ·
Graduate Can torsion avoid the big bang singularity
- Naty1
- · Replies 7 ·
Undergrad Universe expansion beyond c at some distant point?
- k!rl
- · Replies 9 ·
Undergrad Do orbital shapes change from ellipse to parabola to hyperbola with stronger gravity?
- shounakbhatta
- · Replies 2 ·
Undergrad Can you reach absolute zero in complete empty space
- mcafej
- · Replies 14 ·
Undergrad Does redshift reduce the observed temperature of distant stars?
- samsara15
- · Replies 3 ·
Undergrad Importance of a standard candle?
- NanaToru
- · Replies 3 ·
Undergrad Measuring the distance to stars using parallax
- alemsalem
- · Replies 3 ·
Undergrad Interpreting negative declination values in asteroid coordinates
- BOYLANATOR
- · Replies 2 ·
Undergrad Maintaining orbit around the moon
- vjk2
- · Replies 8 ·
Graduate Perpetual acceleration of the universe expansion?
- JuanCasado
- · Replies 6 ·
Graduate Million Kelvin gas clouds? Really?
- Antiphon
- · Replies 16 ·
Graduate Can gravity balance the other forces without mass in zero-energy models?
- Mordred
- · Replies 10 ·
Graduate Formula for the star density of the milky way?
- pere plank
- · Replies 1 ·
Graduate Mechanism for generating the energy in supernova
- mrcotton
- · Replies 10 ·
High School Has Andromeda Moved Closer in 2.5 Million Years?
- jonorion
- · Replies 17 ·
Graduate Why would gravity slow down the Universe's expansion?
- rfoshaug
- · Replies 4 ·
Undergrad What would Earth's gravitational acceleration from the Sun be without Earth?
- cdux
- · Replies 6 ·
On which altitude does the heaven turns in black?
- nickek
- · Replies 5 ·
Undergrad How does parallax of a distant reference object help measure a nearby object?
- NanaToru
- · Replies 3 ·
Undergrad Milkyway Black-hole vs Andromeda Collision
- omar1
- · Replies 1 ·
Graduate Quasar Turn On z<1 Quasar Clustering
- betzalel
- · Replies 2 ·
Graduate Most logical answer for the universe
- WanderingShugo
- · Replies 1 ·
Graduate Flat Universe, dark energy and accelerating expansion
- say_cheese
- · Replies 11 ·
Graduate Why does redshift prove cosmic expansion and not just spacetime expansion?
- Egregious
- · Replies 5 ·
Graduate Can the Multiverse Expand Without a Realm to Expand Into?
- cdux
- · Replies 22 ·
High School Astrophysics Prerequisites Question
- Cjjw
- · Replies 2 ·
Graduate Largest Structure in Universe: 4B Light-Years Long LQG
- Astronuc
- · Replies 2 ·
Graduate Olbers paradox applied to gravity with infinite planets
- cragar
- · Replies 3 ·
Graduate Large quasar group spanning 4 billion light-years challenges cosmological principle
- Tanelorn
- · Replies 1 ·
Undergrad Did Astronauts Face Dangerous Radiation During Apollo Missions?
- inthesky
- · Replies 2 ·
Graduate What you always wanted to know about dark matter?
- wolram
- · Replies 2 ·
Stargazing Celestron UpClose Porro Series 10-30 x 50 Zoom Binoculars
- BH Wiz
- · Replies 4 ·
Undergrad KOI 172.02: 1.5 Earth masses in a 242-day orbit
- Astronuc
- · Replies 1 ·
Graduate Is the Local Fluff Causing Warming in Our Solar System?
- brooklyn2008
- · Replies 3 ·
Undergrad What is the Solar Constant in the Kuiper Belt?
- ninab
- · Replies 1 ·
Graduate Accelerating Universal Expansion
- Maxila
- · Replies 6 ·
Undergrad The lost energy of Cosmic Background Radiation
- JuanCasado
- · Replies 23 ·
Graduate Velocity Dispersion Questions - Shounak
- shounakbhatta
- · Replies 11 ·
Graduate Can we see the Big Bang if particles from it reach us at different speeds?
- Erland
- · Replies 11 ·
Graduate Does an Infinite Universe Challenge the Laws of Thermodynamics?
- Crazymechanic
- · Replies 12 ·
Undergrad Why don't astronomers consider precession as a main movement of Earth?
- Franco Malgari
- · Replies 13 ·
Graduate Why is the universe's existence significant?
- NWH
- · Replies 1 ·
Graduate Planar structure of dwarf galaxies orbiting Andromeda
- TrickyDicky
- · Replies 3 ·
Graduate Can pre-big-bang information survive the crunch?
- anorlunda
- · Replies 12 ·
High School What is the difference between Sagittarius A and Sagittarius A*?
- shounakbhatta
- · Replies 14 ·
Graduate Projected Separation and 3D Distance Problem (Code Included)
- FiberOptix
- · Replies 4 ·
Graduate Similarities of negative absolute temperature to dark energy?
- julcab12
- · Replies 6 ·
Graduate Role of Strong Force in Neutron Stars
- Drakkith
- · Replies 7 ·
Graduate What's the Deal with Astrophysical Jets?
- SHISHKABOB
- · Replies 5 ·
Graduate Relativistic at freeze out? Definition of HDM
- cohen990
- · Replies 2 ·
Undergrad Exoplanet Maps: Northern and Southern Hemisphere Locations
- Bobbywhy
- · Replies 2 ·
High School Does the Milky Way orbit something at its center?
- sprasannaonlin
- · Replies 3 ·
Graduate Does dark matter act as a medium for sound to go through?
- Sk8ernicky
- · Replies 10 ·
Undergrad How does Angular Momentum relate to the rapid rotation of Pulsars?
- AbsoluteZer0
- · Replies 2 ·
Undergrad Stars heat up when they lose energy
- SUDOnym
- · Replies 1 ·
Undergrad The equilibrium in the universe ?
- dido28
- · Replies 8 ·
Graduate Can negative absolute temperatures occur in the cosmos?
- shifty88
- · Replies 1 ·
Undergrad How Does Gravitational Lensing Bend Light in Space?
- shadytriba
- · Replies 3 ·
Undergrad Does a black hole have size if it's collapsed to a singularity?
- goldsax
- · Replies 5 ·
Graduate Alpher Bethe Gamow: Factor characterizing the decrease of density with time
- pianoplayer98
- · Replies 1 ·
High School The Universe. Orderly, Chaotic, or some of both?
- OrionVTOL
- · Replies 29 ·
Undergrad Is it possible at all to go faster in an orbit around the earth?
- vjk2
- · Replies 5 ·
Undergrad Calculating the moon's mass from Earth distance and diameter
- wasi-uz-zaman
- · Replies 4 ·
Graduate Some questions for want of answers:
- Naveen345
- · Replies 10 ·
Graduate How do we determine the production of H and He during BBN?
- pianoplayer98
- · Replies 1 ·
Graduate Planck Intermediate Results. IX. Detection of the Galactic haze with Planck
- d3mm
- · Replies 2 ·
Graduate Distribution of stars by Metallicity and Redshift
- pianoplayer98
- · Replies 4 ·
Stargazing Zhumell Z12 vs Meade Light Bridge 10
- CowedbyWisdom
- · Replies 11 ·
Can the moon be viewed an night at the same time from two positions 77deg apart
- rhizuli
- · Replies 1 ·
Undergrad Which mathematical formulas are used in the search for extraterrestrial planets?
- Gliese123
- · Replies 5 ·
Graduate SPT-SZ Survey Results: New Neutrino Species Suggested
- Chronos
- · Replies 4 ·
Graduate Cannot stand the eternity in cyclic models
- xponential
- · Replies 13 ·
Graduate Can Black Holes Be Used for Faster-Than-Light Travel?
- dbmorpher
- · Replies 2 ·
High School Earth revolves in eliptical path?
- wasi-uz-zaman
- · Replies 2 ·
Undergrad Launching an object into OUTER space
- mrxyz
- · Replies 36 ·
Graduate Mass distribution and gravitational field
- Frank66
- · Replies 6 ·
High School Why is entropy so important in physics?
- Homesick345
- · Replies 21 ·
Graduate Integrating Friedmann Equation of Multi-component universe respect to a and t
- 4everphysics
- · Replies 2 ·
Undergrad How Do You Choose What Scientific Papers to Read?
- Lino
- · Replies 4 ·
Graduate Higher sensitivity CMB mapper (EBEX) launched
- marcus
- · Replies 3 ·