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
Undergrad How did the Moon form?
- HG009
- · Replies 15 ·
Undergrad What if the Universe expands faster than the speed of light?
- peterraymond
- · Replies 19 ·
High School I wonder why massive objects slow down time
- HG009
- · Replies 7 ·
High School Basic confusion about the Big Bang and light cones
- Joseph Flatt
- · Replies 11 ·
Undergrad Would the Hubble constant be different 2.5 billion years ago?
- Thecla
- · Replies 14 ·
High School Question regarding light from distant objects
- Robokop
- · Replies 8 ·
Stargazing Has anyone imaged JWST with amateur telescopes?
- sophiecentaur
- · Replies 39 ·
High School Can the "Dark Energy" concept be wrong?
- jeffinbath
- · Replies 13 ·
High School Does the inertia of matter change in a black hole?
- Carlos Torres
- · Replies 2 ·
Undergrad An idea for calculating the probability that the Universe is flat
- Buzz Bloom
- · Replies 20 ·
Undergrad Can We Predict the Sun's Path from a Single Altitude Measurement?
- roscoe67
- · Replies 12 ·
Undergrad Edwin Hubble and the Evidence for Universe Expansion
- Cerenkov
- · Replies 49 ·
Graduate What assumptions underlie the proof that singularities are inevitable?
- gnnmartin
- · Replies 5 ·
Graduate Relativistic Redshift and understanding it's approximation
- Arman777
- · Replies 4 ·
Graduate Peculiar Acceleration - Understanding an Equation
- Arman777
- · Replies 3 ·
High School How does space expansion differ from objects moving apart?
- Viopia
- · Replies 25 ·
High School Why is the Webb Space Telescope placed at L2?
- brajesh
- · Replies 13 ·
Undergrad Does Dark Matter Have a Temperature?
- binis
- · Replies 25 ·
High School Does dark energy's effect or strength vary over time?
- Cerenkov
- · Replies 24 ·
High School Thoughts on the PBS documentary Chasing the Moon
- dlgoff
- · Replies 1 ·
Undergrad Why does decelerating ship exhaust appear blue-shifted toward Earth?
- Albertgauss
- · Replies 6 ·
Graduate How to derive the equation of state for dark energy
- jordy1113
- · Replies 7 ·
Stargazing Why no Phase Contrast Telescopes?
- Quarker
- · Replies 49 ·
High School An Ancient Solar Storm 9200 years ago is Cause for Concern
- jedishrfu
- · Replies 4 ·
Undergrad Portable telescopes inside the International space station (ISS)
- akerkarprashant
- · Replies 4 ·
Undergrad Calculating finite universe radius from Planck 2018 data
- Buzz Bloom
- · Replies 12 ·
High School The Colors of The Moon (Doppler Effect)
- dom_quixote
- · Replies 3 ·
Undergrad A relationship between flat vs. finite and (2) Hubble constant tension
- Buzz Bloom
- · Replies 21 ·
Undergrad Antimatter-matter asymmetry, Law of charge
- Sciencelad2798
- · Replies 8 ·
High School What are the potential causes of the universe's eventual demise?
- frost_zero
- · Replies 1 ·
Undergrad SN 2019hgp, new type of supernova? Wolf-Rayet progenitor?
- Astronuc
- · Replies 0 ·
High School Size of the universe at different epochs after the Big Bang
- KingGambit
- · Replies 58 ·
Undergrad Balmer Absorption Lines in Different Temperature Stars
- Albertgauss
- · Replies 3 ·
Undergrad Is the animation/graphics for NASA's Webb telescope in error?
- swampwiz
- · Replies 9 ·
High School Does dark energy or cosmic inflation explain flatness?
- RogerWaters
- · Replies 37 ·
High School How do the candidates for Dark Energy 'work'?
- RogerWaters
- · Replies 4 ·
Undergrad Could the Universe's Early State Be a Superposition of High and Low Entropy?
- Adrian Lee
- · Replies 4 ·
High School Understand Bonnar-Ebert Model: Complement to Jeans Law?
- Phigla
- · Replies 5 ·
High School Does the CMB itself tell us that it started at 3000K?
- clawsoon
- · Replies 23 ·
Graduate How Do Recent Studies Impact Our Understanding of CMB Anomalies?
- Adrian Lee
- · Replies 16 ·
Undergrad How do Gaia and DESI star maps differ and complement each other?
- Hillwalker01
- · Replies 1 ·
Undergrad Must a sensor be as thick as the wavelength it detects?
- LightningInAJar
- · Replies 1 ·
Undergrad Can the big rip ever be ruled out?
- Trollfaz
- · Replies 2 ·
Undergrad Is the false vacuum theory not well accepted?
- Trollfaz
- · Replies 1 ·
High School What is the mass distribution and rotation curve of galaxy IC1101?
- Buckethead
- · Replies 4 ·
High School What Space Does the Universe Occupy?
- HailSagan
- · Replies 4 ·
Undergrad Jupiter atmosphere, turbulence and ocean fluid dynamics
- Astronuc
- · Replies 0 ·
High School Why doesn't cosmic inflation violate conservation of energy?
- RogerWaters
- · Replies 3 ·
Undergrad Are two-body orbits with a cosmological constant unstable?
- kimbyd
- · Replies 26 ·
Undergrad Equivalence of Universe Accelerating Expansion?
- Mathchallenged
- · Replies 9 ·
Undergrad Force of gravity on JWST while orbiting L2
- Eugene
- · Replies 4 ·
Graduate Viewing Constellations from Opposite Hemispheres
- abhiask11
- · Replies 9 ·
Undergrad Does gravity compress matter in planets?
- Dreksler
- · Replies 9 ·
Undergrad We watched a red supergiant explode to ordinary type II supernova
- Tom.G
- · Replies 4 ·
High School Accelerating expansion of the Universe
- Jupiter60
- · Replies 6 ·
High School Earth's orbit and the expansion of the Universe
- Randy Subers
- · Replies 27 ·
Undergrad Do Stars Fuse Elements Heavier Than Iron Before Imploding?
- LightningInAJar
- · Replies 4 ·
High School Lunar libration time lapse with real photographs?
- Warp
- · Replies 1 ·
Undergrad Why does Andromeda approach us if the universe is expanding?
- abdossamad2003
- · Replies 12 ·
High School Propellant generation via Breit-Wheeler process for interstellar propulsion
- dansmith170
- · Replies 19 ·
Undergrad How is light modeled in astrophysics?
- Haorong Wu
- · Replies 1 ·
Undergrad How to change CSpice initial velocity from an Asteroid SPK file?
- forofo
- · Replies 2 ·
Stargazing Why does the Chandrasekhar mass calculation give units of kg³?
- MarkL
- · Replies 5 ·
High School What is the relationship between expansion and curvature?
- RogerWaters
- · Replies 20 ·
High School What If Universes Were Made of Antimatter?
- Quarker
- · Replies 11 ·
High School Black hole and antimatter star head-on collision and annihilation
- smplcrtrs
- · Replies 5 ·
High School Why does gnomon height depend on latitude in a horizontal sundial?
- Luxdot
- · Replies 10 ·
Undergrad Cosmological Positioning - How does one determine?
- Gary0509
- · Replies 6 ·
Stargazing 3D/2D Universe Model (DSO, stars etc.)
- Arman777
- · Replies 1 ·
Undergrad Do all geodesics begin and end at the big bang?
- gregatphysics
- · Replies 6 ·
High School Did the universe have to start with equal matter and antimatter?
- Randy Subers
- · Replies 27 ·
High School What do they mean when they say something is so many light years away?
- HankDorsett
- · Replies 18 ·
Undergrad Is EK Draconis' binary status a factor in its ability to produce large CMEs?
- Astronuc
- · Replies 4 ·
Undergrad How long did inflation last in an eternal inflating universe?
- elcaro
- · Replies 35 ·
Stargazing Level of details in prime focus vs eyepiece images
- PhysicoRaj
- · Replies 226 ·
Graduate Calculating the variance of integrated Poisson noise on a defined quantity
- fab13
- · Replies 36 ·
Undergrad How Big of an Object Orbiting Closer to the Sun Than Earth Could Be Overlooked?
- ohwilleke
- · Replies 17 ·
Undergrad Can supermassive black holes account for Bullet Cluster lensing?
- Delisso
- · Replies 16 ·
Graduate How Does the Ring Current Persist Despite Short-Lived Particle Drift?
- carlos-carlos
- · Replies 1 ·
Undergrad Why is the Big Bang shown always directional, instead of globally?
- two OLD 2 care
- · Replies 6 ·
High School What is the relationship between inflation and the expansion of our universe?
- lotsofquestions
- · Replies 1 ·
Undergrad What is the origin of spatial inhomogeneities in the Universe?
- sergiokapone
- · Replies 2 ·
High School Could satellite be geo-stationary away from equatorial plane?
- xtempore
- · Replies 5 ·
Undergrad What are the Coordinates of Sagittarius A* at Different Julian Century Dates?
- Philosophaie
- · Replies 2 ·
Undergrad History of astronomy and the Phases of Venus
- windy miller
- · Replies 4 ·
Graduate Molecular cloud collapsing and fragmentation
- Phigla
- · Replies 4 ·
Undergrad Ultraluminous X-ray source in the galaxy NGC 55
- Astronuc
- · Replies 0 ·
Undergrad A New Idea for the Origin of Earth's Water
- dougettinger
- · Replies 1 ·
Undergrad Dark Matter as a condensation of photons in a space
- ahmashojaeddin
- · Replies 1 ·
High School Process of a sun changing into a white dwarf
- songoku
- · Replies 5 ·
Undergrad EDE - Solving the Klein - Gordon Equation for a scalar field
- Arman777
- · Replies 1 ·
Undergrad What does the anthropic principle explain?
- Sciencelad2798
- · Replies 3 ·
High School Is There a Theoretical Center in a Finite Universe?
- thetexan
- · Replies 6 ·
High School Observers sending signals to measure expansion
- BWV
- · Replies 5 ·
Undergrad Is the Hubble constant a constant or is it a parameter?
- Angela G
- · Replies 8 ·
Undergrad What is Compton drag in cosmology?
- edgarpgovea
- · Replies 1 ·
Undergrad How fast is the solar system accelerating, and could we trace Oumuamua's origin?
- DeckSmeck
- · Replies 14 ·
Undergrad What is the average distance between objects in the Kuiper belt?
- abdossamad2003
- · Replies 6 ·
Graduate How is the Temperature of Gas in a Cluster Calculated?
- physgeek2033
- · Replies 1 ·
Undergrad Reading Paper on Earth Occultation Technique
- yucheng
- · Replies 1 ·