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 Does time run fast near universe's edge?
- ksertatas
- · Replies 6 ·
Stargazing How clearly can an 80 mm refracting telescope show Saturn and Titan?
- FreeMitya
- · Replies 5 ·
Graduate Correct interpretation of terms in proper velocity expression?
- johne1618
- · Replies 4 ·
High School Gravitational Constant: Questions and Ideas
- Numeriprimi
- · Replies 2 ·
Undergrad How does momentum dumping work on the Hubble Space Telescope?
- Fi-reefly
- · Replies 2 ·
Graduate Can a Spacecraft Achieve Light Speed Using Jupiter's Magnetic Field?
- sr241
- · Replies 4 ·
Graduate What is the Color of a Neutron Star?
- Jarfi
- · Replies 43 ·
Stargazing How do radio telescopes form images?
- Drakkith
- · Replies 18 ·
Graduate Measurment that proves that the universe is flat
- alkmini
- · Replies 8 ·
Undergrad How to convert flux from counts to erg.
- RHK
- · Replies 3 ·
Graduate Expansion of Universe but no expansion of galaxies
- BOYLANATOR
- · Replies 14 ·
Graduate Are there non-spherical blackholes?
- Lino
- · Replies 4 ·
Stargazing World’s largest Cherenkov telescope opens
- edguy99
- · Replies 6 ·
Graduate Is the speed of light constant for a co-moving observer?
- johne1618
- · Replies 14 ·
Graduate Are rays from opposite sides of a hot spot of CMB parallel or not?
- alkmini
- · Replies 6 ·
Undergrad Urban Space Saving: Reducing Traffic with Raised Roadways and Shops
- LughGlas
- · Replies 1 ·
High School Does the Earth actually revolve around the Sun
- Manula
- · Replies 23 ·
Graduate How do we know how hot the big bang was from the CMB?
- wolram
- · Replies 9 ·
Graduate Is age of universe adjusted for gravity?
- KenJackson
- · Replies 6 ·
Undergrad Can Amateur Telescopes Detect Exoplanets?
- SpaceDreamer
- · Replies 11 ·
High School Planet Found Orbiting Alpha Centauri
- Drakkith
- · Replies 31 ·
Graduate Does energy dilate time like mass?
- KenJackson
- · Replies 1 ·
Graduate Problem interpreting Mpc/h in maps of DM
- BillSaltLake
- · Replies 3 ·
Undergrad Just how dark is Pluto from orbit? How about Saturn?
- wedouglas
- · Replies 9 ·
Undergrad Position and angle of Earth/Moon/Sun and timing
- TouTorp
- · Replies 1 ·
High School Can I see stars through the moon?
- paddys09
- · Replies 13 ·
Undergrad Could Ice Form Inside the Sun?
- nefertum
- · Replies 4 ·
Undergrad What is the Scientific Understanding of Gravity?
- Backus
- · Replies 21 ·
Interesting simulation of a spiral galaxy evolution.
- Spinnor
- · Replies 5 ·
Undergrad What Determines the Diameter of a Moon Halo?
- jmvizanko
- · Replies 1 ·
Graduate Fundamental Cosmology conference (Stockholm, November 2012)
- marcus
- · Replies 0 ·
High School Did Mars Once Have Flowing Water?
- shifty88
- · Replies 14 ·
Graduate What is the distance needed for a rocket to reach a velocity of 0 on Planet X?
- scoop91
- · Replies 6 ·
Graduate Can Shock Waves Initiate Protostar Formation?
- hunt_mat
- · Replies 3 ·
Undergrad Apparent size of comets in images from the SOHO satellite
- Ostsol
- · Replies 4 ·
Graduate How can the Universe be flat and accelerating in its expansion?
- *FaerieLight*
- · Replies 2 ·
High School What is the age of the universe in billions?
- ofeyrpf
- · Replies 9 ·
Graduate Direct determination of expansion history using redshift distortions
- Chronos
- · Replies 8 ·
Graduate Is My Proper Time the Same as Cosmological or Conformal Time?
- johne1618
- · Replies 2 ·
Graduate Looking for other proof of expanding universe.
- grounded
- · Replies 75 ·
Graduate Is Heat Death or the Big Rip Inevitable in an Open Universe?
- wolram
- · Replies 20 ·
Graduate Understanding Spectra Shifts of Distant Stars
- Ezio3.1415
- · Replies 10 ·
Undergrad Big Bang Questions: How Far, How Long, Possible?
- guitarphysics
- · Replies 3 ·
Graduate Energy in co-moving co-ordinates?
- johne1618
- · Replies 7 ·
Graduate Difference between the Higgs field and the Inflaton field?
- friend
- · Replies 7 ·
Graduate Periodicity in the mass of planets?
- Morgaen
- · Replies 5 ·
Graduate Can universes collide with each other in an eternally inflating multiverse?
- mustang19
- · Replies 16 ·
High School How far back in the universe's history before any life existed?
- GoodUniverse
- · Replies 38 ·
Graduate Cosmological constant from first principles
- Chronos
- · Replies 9 ·
Undergrad Is Retro-Rocket Still a Relevant Term for Slowing Down Satellites?
- Smileyxx
- · Replies 14 ·
Graduate Consequences of a negative mass universe
- olso4051
- · Replies 5 ·
High School Can a person catch an object in space and stop it without being pulled along?
- Ivan452
- · Replies 1 ·
Graduate How are the component densities in the LCDM model determined?
- mysearch
- · Replies 10 ·
Graduate Does Light Exist Outside Time?
- mugenshiyo
- · Replies 8 ·
Undergrad Can someone explain abberation of starlight?
- Pharaoness
- · Replies 3 ·
Graduate Could cosmic voids be solid inelastic bodies rotating slowly?
- codex34
- · Replies 4 ·
Undergrad How Does the Moon Influence Earth's Rotation and Orbit?
- Rick James
- · Replies 4 ·
Why pursue space colonization when ocean colonization is more realistic
- Monsterboy
- · Replies 14 ·
Graduate Observable Universe and Black Holes
- sefer
- · Replies 3 ·
Graduate Vogt-Russell theorem and stellar structure modelling
- po6
- · Replies 2 ·
Undergrad Can a finite universe without a center have a center of mass?
- nemoover
- · Replies 6 ·
Graduate Temperature of planets from their Luminosities at specific wavelengths.
- mystupidmouth
- · Replies 12 ·
Graduate Are spacetime crystals theoretically possible?
- Light Bearer
- · Replies 4 ·
Graduate Evidence of Cosmic Backround Radiation cooling
- Bill Minerick
- · Replies 5 ·
Graduate Gravity Assist Oberth Effect Sun
- Albertgauss
- · Replies 4 ·
Graduate Simple argument for a linear cosmology
- johne1618
- · Replies 10 ·
Graduate Dark Matter as possible ground state for all matter
- Bill Minerick
- · Replies 2 ·
Graduate Why does our universe/dimension follow the laws that it does?
- Niaboc67
- · Replies 2 ·
Undergrad Is Dark Rift a Rotating Cloud or a Dust Belt Surrounding the Galactic Center?
- ShayanJ
- · Replies 4 ·
Graduate Higgs Boson and Dark Matter / Dark Energy
- Velcro
- · Replies 11 ·
Graduate Jupiter and Saturn - Back and Forth in the Early Solar System?
- lpetrich
- · Replies 3 ·
Graduate Co-moving density should be constant?
- johne1618
- · Replies 14 ·
Graduate Perfect cosmological principle in co-moving co-ordinates
- johne1618
- · Replies 4 ·
Where can I find historical solar activity data to check current trends?
- DanSolo
- · Replies 8 ·
Graduate Many Worlds + Anthropic Principle
- kamikaze762
- · Replies 21 ·
Graduate Could singularity spin determine if our universe is matter or antimatter?
- Dappy
- · Replies 1 ·
Graduate How did gravity build astronomical objects that rotate?
- Paulibus
- · Replies 31 ·
Graduate Does the Milky have a QSO? What is the observational evidence concerning QSOs?
- betzalel
- · Replies 24 ·
Graduate Universe was the size of our solar system after 1 sec
- kjamha
- · Replies 15 ·
Undergrad What if the Moon orbited backwards relative to Earth's rotation?
- DeepSpace9
- · Replies 17 ·
Graduate How would Earth mass loss theoretically affect its orbital mechanics?
- mofobro
- · Replies 12 ·
Undergrad Can galaxies change direction between when light was emitted and when we observe it?
- gway22
- · Replies 2 ·
Undergrad Is the Expansion of the Universe Slowing Down?
- NWH
- · Replies 15 ·
Graduate Can MACS 1149-JD have formed just 300 million years after the Big Bang?
- Tanelorn
- · Replies 24 ·
Undergrad Why do stars have different colors?
- gmax137
- · Replies 13 ·
Graduate Attempting to image Fomalhaut's debris disk with limited equipment
- Drakkith
- · Replies 4 ·
Graduate How Are Fluid Solutions Used in Astrophysics and Cosmology?
- shounakbhatta
- · Replies 19 ·
Graduate How is mass distribution understood within the LCDM cosmological model?
- mysearch
- · Replies 5 ·
Graduate Angular Velocity of a Nebula Accretion Disk
- Vodkacannon
- · Replies 1 ·
Graduate How much space mining would begin to affect earth
- VegaMan
- · Replies 8 ·
Graduate Creating artificial ultradense objects by ablation implosion?
- monstermacina
- · Replies 23 ·
Graduate The Kantian Wall - The Meaning of Space, Time, and Mass in Modern Physics
- arupel
- · Replies 1 ·
Graduate Big Bang inflation/expansion vs centre of universe vs Speed of light query
- learningmore
- · Replies 28 ·
Graduate The First Law of Thermodynamics VS. The Universe Created from Nothing
- B.M.Gray
- · Replies 16 ·
Why is the Universe So Complex and What Should I Do About My Existential Crisis?
- genius01
- · Replies 1 ·
Graduate Where did the matter in the big bang come from?
- wasteofo2
- · Replies 66 ·
Graduate What does it mean that time is expanding?
- darrenr
- · Replies 10 ·
Graduate How to Generate Accurate Initial Conditions for Simulating Galaxy Dynamics?
- fab13
- · Replies 2 ·
Graduate Do Solar Systems with Eccentric Planets Have More Stable Orbits?
- Philosophaie
- · Replies 29 ·
Undergrad Q about moon and sun tides, energy related to comet strikes and the mass water?
- aw07
- · Replies 1 ·