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 Space-Time a Continuum or a Physical Object?
- TrickyDicky
- · Replies 47 ·
Undergrad Rocky Bits in Comets: Formation from Dust?
- anorlunda
- · Replies 2 ·
Graduate If the speed of light was greater, how would it show up?
- GeorgeBaxter
- · Replies 5 ·
Graduate Spectral energy distributions of white dwarfs in 47 Tucanae
- GiantSheeps
- · Replies 2 ·
Graduate Why does the CNO cycle's final reaction produce carbon-12, not oxygen-16?
- sunrah
- · Replies 10 ·
Graduate Convection vs Radiation at the giant stage of stars
- center o bass
- · Replies 3 ·
Graduate The Fastest Unbound Stars in the Universe
- marcus
- · Replies 1 ·
Undergrad How Does Rosetta Maintain Its Position Relative to the Comet?
- docroc
- · Replies 8 ·
High School What Are Some Cool Facts About Galaxies and Stars for a School Project?
- Kostas Tzim
- · Replies 6 ·
Undergrad Average distance among pieces of space debris in low earth orbit?
- Kevin Le
- · Replies 3 ·
Graduate Why is the Cosmological Redshift z Confusing?
- AlephClo
- · Replies 5 ·
High School Layman question on sun as seen from mercury
- Constantinos
- · Replies 3 ·
Graduate I want to spread life to space. What should I do?
- lowerlowerhk
- · Replies 12 ·
Graduate About the effects of relativity when measuring the age of the universe
- tonyxon22
- · Replies 2 ·
Undergrad Why does the sun appear to move eastwards from Earth?
- amenhotep
- · Replies 5 ·
Graduate Is there a boundary present for our universe?
- aditya ver.2.0
- · Replies 17 ·
Graduate How Is the Age of the Universe Measured Given Relativity and Expansion?
- gamow99
- · Replies 9 ·
Undergrad Active Region AR2192 heading towards the limb
- davenn
- · Replies 2 ·
Undergrad About the size of the Universe and distance between galaxies
- tonyxon22
- · Replies 12 ·
Graduate How do E Folds relate to real distance?
- wolram
- · Replies 2 ·
Graduate Have theories been formed yet on how to stop a black hole?
- Siddharth Menon
- · Replies 29 ·
Alternatives to heat death as the ultimate fate of the universe
- Gaz1982
- · Replies 8 ·
Graduate Can surface brightness determine cosmological parameters?
- ChrisVer
- · Replies 3 ·
Graduate How to understand Friedman equation
- cyc454
- · Replies 11 ·
Graduate Excluding a simple dark matter candidate
- Ilja
- · Replies 1 ·
Undergrad Which fate awaits the universe: big freeze, big rip, big crunch, or big bounce?
- wolram
- · Replies 37 ·
Graduate Why can the universe be expanding inward away from point of singularity (POS)?
- HZY
- · Replies 27 ·
Graduate First Measurement of the Ancient Solar System's Magnetic Field
- CygnusX-1
- · Replies 1 ·
High School Can a Camera Be Built to See Stars in Daylight?
- exponent137
- · Replies 18 ·
Undergrad Our galaxy is one of the biggest
- Niaboc67
- · Replies 4 ·
Graduate Is the Universe Heading Towards a Big Crunch or Eternal Expansion?
- gangula pranav
- · Replies 1 ·
Graduate Matter at the core of neutron star
- Vrbic
- · Replies 6 ·
Graduate Half of All Stars in Galactic Halos: Potential to Rethink Mass Estimates?
- jim mcnamara
- · Replies 4 ·
Undergrad Flux --> Apparent magnitude ( only 1 source )
- SpaceNerdz
- · Replies 1 ·
Graduate How can we see distant objects if they were closer in the past?
- ckirmser
- · Replies 8 ·
Graduate Pairwise velocity dispersion in Cosmological simulations
- sketos
- · Replies 6 ·
Undergrad The mass of the sun at its beginning
- elegysix
- · Replies 3 ·
Graduate Does the Universe always have the same mass, or can it leak into other realms?
- Gaz1982
- · Replies 19 ·
Graduate Why Does the Hubble Sphere Expand Despite the Changing Hubble Constant?
- gangula pranav
- · Replies 6 ·
Graduate Interstellar the movie and real physics
- Duhoc
- · Replies 1 ·
Undergrad How could the universe come from nothing before the Big Bang?
- astrobmw
- · Replies 2 ·
Graduate Is Newton's third law applicable everywhere?
- ARKA BASU
- · Replies 6 ·
Graduate Solar System Dynamics, advice for a intern.
- MLTstudent
- · Replies 1 ·
Graduate Proton-electron mass ratio; changed? how much?
- tomn44
- · Replies 6 ·
Undergrad Why do spiral galaxies look symmetric if their light takes so long to reach us?
- CutThroatJake
- · Replies 9 ·
Undergrad Calculating the sun's luminosity from solar constant
- mokeejoe5
- · Replies 3 ·
Undergrad Solar System inside a black hole
- !Jon Snow!
- · Replies 3 ·
Graduate What Theories Exist About the Edge of the Universe?
- Quiksilver421
- · Replies 4 ·
Graduate What is the Ideal System for Running a Nuclear-Powered Heat Engine in Space?
- vemvare
- · Replies 12 ·
Ison Comet will be brighter than the moon
- Franco Malgari
- · Replies 27 ·
Have you seen the meteoric smoke-ring?
- B0b-A
- · Replies 4 ·
Graduate Can I Use a Telecentric Lens with an Afocal Telescope?
- cboptics
- · Replies 1 ·
Graduate Why does the universe have nearly flat spatial curvature according to observations?
- TRB8985
- · Replies 27 ·
Undergrad Fire in Low Gravity: Visualizing a Biodome Blaze
- jaidanwolf
- · Replies 5 ·
Graduate How Did Supermassive Black Holes Grow So Massive So Quickly?
- wolram
- · Replies 4 ·
Graduate Schonberg-Chandrasekhar mass for low mass stars
- Sherrod
- · Replies 4 ·
Undergrad Calculating black hole mass for Cygnus X-1
- JDenise
- · Replies 9 ·
Graduate Plank length / space expansion question
- Grinkle
- · Replies 5 ·
Graduate Can we see radiation from an event that happened before matter formed?
- adoion
- · Replies 24 ·
"Planet formation captured in photo"
- Spinnor
- · Replies 1 ·
How did humans set the first reference point for days of the week?
- william7580
- · Replies 2 ·
Graduate Does Antimatter exist in the universe anymore?
- Nova
- · Replies 44 ·
Graduate What are peoples thoughts on the fact that at the exact limit of our universe.
- jbander
- · Replies 6 ·
Graduate Is Dark Energy the Answer to the Accelerating Universe and Big Bang Conundrums?
- rogerpendleto
- · Replies 3 ·
Graduate What is the Breakdown of the Milky Way's Mass?
- JoeOfTexas
- · Replies 3 ·
Graduate How Did the First Stars Form Without Supernova Compression?
- kuartus4
- · Replies 1 ·
Undergrad How did Einstein know the properties of space and time
- Niaboc67
- · Replies 4 ·
Alan Guth:Inflationary Cosmology live stream 10/31
- TumblingDice
- · Replies 2 ·
Undergrad Can someone explain the mathematics of this formula for Venus' orbit
- Niaboc67
- · Replies 5 ·
Virgin Galactic's SpaceShipTwo Lost in Test Flight; One Pilot Reported Dead
- Evo
- · Replies 39 ·
Undergrad How can we see light from the Big Bang if we all expanded from the same origin?
- nobody special
- · Replies 12 ·
Graduate Does Positive Curvature Dominate FRW Cosmological Models in Inflation Theory?
- TrickyDicky
- · Replies 12 ·
Graduate What prevents a star from collapsing after stellar death?
- avito009
- · Replies 51 ·
Undergrad What Came Before the Big Bang?
- megapyab
- · Replies 38 ·
Graduate Does space expansion cause cosmological redshift or vice versa?
- jerromyjon
- · Replies 11 ·
Graduate Zero gravity in spiral galaxy center?
- protonic_mass
- · Replies 5 ·
High School Tides: Does Moon's Rotation Affect Earth?
- nicolauslamsiu
- · Replies 1 ·
Graduate Big Bang ruled out as origin of lithium-6
- TrickyDicky
- · Replies 33 ·
Graduate Cosmological redshift: Where does the energy go?
- ellipsis
- · Replies 2 ·
Mom's New Camera Captures the Night Sky!
- Yadama
- · Replies 5 ·
Graduate Unorthodox "space" elevator idea
- serp777
- · Replies 3 ·
Graduate Could the Event Horizon of black holes be the edge of expanding universes?
- alexandersteele
- · Replies 1 ·
Undergrad Why do galaxies and solarsystems form disks?
- Nova
- · Replies 4 ·
Graduate Frame dragging effect on a satellite orbiting opposite to the sun's rotation
- SreenathSkr
- · Replies 4 ·
High School The Space Between Atoms -- Teaching Middle School
- leeone
- · Replies 37 ·
Undergrad Does the sun always rise to the right of magnetic north on any planet?
- jjustinn
- · Replies 6 ·
High School UFO or Dead Pixel? What's Flying Across the Moon?
- B0b-A
- · Replies 9 ·
Undergrad Why does space expansion cause redshift?
- ricardo81
- · Replies 43 ·
Undergrad Why do the constellations appear to move differently in different seasons?
- Pjpic
- · Replies 6 ·
Graduate BH to Sun, back of the napkin calculation of solar mass
- elegysix
- · Replies 6 ·
Undergrad How can we say space is expanding if galaxies are just moving apart?
- ggolu2
- · Replies 7 ·
Graduate How/why are pocket universes created during eternal inflation?
- phyguuy
- · Replies 39 ·
Graduate Zero-point energy density evaluation
- Helios
- · Replies 19 ·
Graduate SGP4 propagation of ISS TLE showing incorrect altitude and date
- thor36
- · Replies 1 ·
Undergrad Can a planet with a thin atmosphere have oceans?
- willstaruss22
- · Replies 23 ·
Graduate Which Stars Cast the Milky Way's First Light?
- CygnusX-1
- · Replies 3 ·
Graduate Stars that look older than the universe
- wolram
- · Replies 5 ·
High School Finding M31 from light-polluted suburbs with a 6SE telescope
- Ritzycat
- · Replies 10 ·
Graduate Question regarding to acceleration in the rate of expansion of our cosmos
- aditya ver.2.0
- · Replies 3 ·
Graduate Is CNO cycle more life friendly than H->He?
- tzimie
- · Replies 23 ·