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 Questions about the Voyager spacecraft
- abdossamad2003
- · Replies 32 ·
Undergrad How Does Earth's Rotation Vary Daily?
- abdossamad2003
- · Replies 6 ·
Undergrad Relativistic Doppler Effect near a Black Hole
- appot89
- · Replies 2 ·
Undergrad Image for increase in gravitational potential energy in radial field
- hexcalibur
- · Replies 6 ·
High School Mass transfer between neutron stars in a binary pair
- Andy DS
- · Replies 4 ·
Graduate Is this MOND advance a big deal?
- Frabjous
- · Replies 6 ·
Undergrad How do gravitational waves differ from the expansion of the Universe?
- Andy DS
- · Replies 12 ·
Undergrad Why do gravitational waves travel at the speed of light?
- brucegoth123
- · Replies 2 ·
Undergrad Bias and dark current from a graph of mean signal vs exposure time
- beans123
- · Replies 1 ·
Undergrad Why aren't Gravitational waves factored in to inflation formulas?
- Barque
- · Replies 9 ·
Undergrad What are the Cosmological monopole and dipole?
- jordy1113
- · Replies 3 ·
Undergrad Composition of Jupiter: Ices, Cores & Outer Gas Layers
- curious_ocean
- · Replies 24 ·
Undergrad The definition of volume inside black hole?
- Charles_Xu
- · Replies 19 ·
High School Stars massive enough to evolve into black holes
- DaveC426913
- · Replies 5 ·
High School Name of projection to firmamentum (celestial sphere)
- DrDu
- · Replies 6 ·
High School Navigating To Another Star System
- happyhacker
- · Replies 6 ·
High School No way to catch up with galaxies currently receding at >c?
- Comradez
- · Replies 5 ·
Graduate COG calculation of diffracted spots on a camera
- Gifty01
- · Replies 3 ·
Graduate Can Background Radiation Serve as a New Coordinate System in Astronomy?
- darkdave3000
- · Replies 19 ·
Undergrad Stromgren photometric data in Vizier
- yucheng
- · Replies 7 ·
Undergrad Simulation debugging for Apollo Lunar Landing
- darkdave3000
- · Replies 22 ·
Undergrad Encircled energy for different aperture shapes (circle, triangle, square)
- Gifty01
- · Replies 4 ·
High School Question re Webb telescope at L2
- Buzz Bloom
- · Replies 1 ·
High School Visit to Hayden Planaterium -- The projector is gone?
- Thecla
- · Replies 3 ·
Undergrad Issue with Stellarium: transit of Venus (find the parallax)
- yucheng
- · Replies 7 ·
Stargazing Better than Mars Colonization in many aspects.
- Deep Sciences
- · Replies 3 ·
Undergrad How well do cosmological models explain the observed µ vs. z data?
- JimJCW
- · Replies 10 ·
Stargazing Star appearing to move ping pong like rapidly
- Bm23
- · Replies 7 ·
Graduate Obtaining the noise level of a camera
- Gifty01
- · Replies 9 ·
Undergrad Confused about declination, elevation & altitude
- swampwiz
- · Replies 3 ·
Stargazing Does an Analemma visualize the Earth's actual orbit around the sun?
- lolsurround
- · Replies 4 ·
Undergrad What's left to see of the early Universe?
- SimplePrimate
- · Replies 3 ·
High School Radiation Levels at Earth's Poles
- Jaziel
- · Replies 6 ·
Undergrad Inflation and size of the Universe
- Ranku
- · Replies 29 ·
Undergrad Collision between the Milky Way and Andromeda and Redshift
- MartinG
- · Replies 6 ·
Stargazing Troubleshooting My Orion 130 Reflector
- Brian Muller
- · Replies 11 ·
Undergrad What Are the Origins of the Universe?
- Ads the devil
- · Replies 17 ·
Undergrad Cosmological principle about space and time
- elcaro
- · Replies 20 ·
High School Is an infinite universe compatible with cyclic models?
- TheHeraclitus
- · Replies 1 ·
High School Acceleration of time due to entropy
- R0dr1go
- · Replies 1 ·
High School Confused About the Source of CMB Photons: Two Possibilities
- Nathi ORea
- · Replies 7 ·
Undergrad About the relation between number of sidereal and solar days
- cianfa72
- · Replies 27 ·
High School According to current physics, is vacuum still something or nothing?
- Rev. Cheeseman
- · Replies 40 ·
High School How long it takes the Earth to fall halfway to the Sun--ellipse method
- bruhh
- · Replies 3 ·
Undergrad Curvature Index in Flat Universe with Cosmological Constant?
- Ranku
- · Replies 3 ·
High School Delta-v from Lagrange points to lunar surface?
- Treva31
- · Replies 5 ·
Undergrad So I wrote a book on cosmology....
- mbond
- · Replies 4 ·
Undergrad Assumptions for blackbody spectra vs. emission spectra vs. absorption spectra
- curious_ocean
- · Replies 8 ·
Stargazing Calculating the Resolving power of a Telescope
- RhysGM
- · Replies 7 ·
Undergrad On the assumption of an infinite universe
- dx
- · Replies 17 ·
Undergrad Can someone explain Quasi-steady-state cosmology to me?
- TheHeraclitus
- · Replies 2 ·
Undergrad What is the acceleration of the expansion of the Universe?
- JamesGarderiner
- · Replies 7 ·
High School Is there a way of creating placemarks in Stellarium?
- Beth Doodle
- · Replies 8 ·
Graduate Analemma layout and proportions on a sundial
- 1940LaSalle
- · Replies 1 ·
Graduate Add factor Δℓ or Δℓ^2 in the variance for integrated Shot noise
- fab13
- · Replies 9 ·
Undergrad Newton's 3rd law and ether in space
- appot89
- · Replies 3 ·
High School Are there more theories about the start of our Universe?
- Chiefly
- · Replies 22 ·
High School Question about the solar system and gravitational forces
- Sundown444
- · Replies 10 ·
Undergrad The CMB drag on an object moving through space
- JimJCW
- · Replies 6 ·
Undergrad Is acceleration a more absolute/fundamental quantity in the universe?
- cometraza
- · Replies 16 ·
Undergrad What does Causality really mean?
- InfiniteMonkey
- · Replies 7 ·
Undergrad Energy conservation in an expanding universe
- elcaro
- · Replies 2 ·
Graduate Introduction of a factor Δℓ when summing equal distants 𝐶ℓ
- fab13
- · Replies 5 ·
Undergrad Planetary Formation: Could Collisions Explain Our Solar System?
- guesses3
- · Replies 52 ·
Undergrad Is There Evidence to Suggest Our Universe is Anisotropic?
- ohwilleke
- · Replies 8 ·
High School Pressure under the ice of Europa?
- GTOM
- · Replies 9 ·
High School Can we measure acceleration of galaxies and stars?
- elcaro
- · Replies 1 ·
Undergrad What Are These Mysterious Objects Spotted Near Orion?
- Hijole
- · Replies 10 ·
Undergrad Evidence for existence of a 9th Planet in the solar system
- Zeeshan Ahmad
- · Replies 15 ·
Graduate Cl's : sum into a chi^2 when we have a sum of chi^2
- fab13
- · Replies 6 ·
High School Why does MOND fit rotation curves so exactly?
- wolram
- · Replies 14 ·
Undergrad Can magnetic fields explain anomalous galaxy rotation curves?
- elcaro
- · Replies 2 ·
Undergrad Is the existence of a Dyson Sphere impossible?
- HystereeSis
- · Replies 3 ·
Undergrad Dark matter + gravity is 'right', or our understanding of gravity is wrong?
- cmb
- · Replies 35 ·
Undergrad Could Titan Be Our Next Home for Colonization?
- swampwiz
- · Replies 1 ·
Undergrad Is Dark Matter Composed of Low-Mass Particles?
- Ranku
- · Replies 1 ·
High School Traveling to alternate universes
- imagIne71
- · Replies 15 ·
Graduate Analytical expression of Cosmic Variance - Poisson distribution?
- fab13
- · Replies 1 ·
Undergrad Does a photon travel freely through the CMB photon gas?
- JimJCW
- · Replies 10 ·
Undergrad Is it time to take the 'bang' out of the Big Bang?
- elcaro
- · Replies 4 ·
Undergrad What atoms are we made of, how much is from the big bang?
- cmb
- · Replies 2 ·
Undergrad Shouldn't the Big bang be physically impossible?
- Mr J
- · Replies 25 ·
Undergrad Could dark matter consist of primordial black holes?
- Prishon
- · Replies 20 ·
High School Please help in explaining 'we are not the center of the Universe'
- Dan Rozenfarb
- · Replies 21 ·
Undergrad Did cosmic inflation happen everywhere in the Universe?
- RobertSpencer
- · Replies 80 ·
High School Question on paper: Inflationary spacetimes are not past-complete
- Lynch101
- · Replies 16 ·
Undergrad Acceleration of Universe Expansion: 1/r2
- Gannet
- · Replies 24 ·
Undergrad What happened to the range of frequencies after recombination?
- artis
- · Replies 27 ·
Undergrad Orbital distance increase during the white dwarf phase of the Sun
- Dreksler
- · Replies 1 ·
High School Definition of Stellar Parallax from Alonso and Finn Volume 1
- vibha_ganji
- · Replies 3 ·
Undergrad Black holes and relation to creation
- eodrogerrich
- · Replies 2 ·
High School How Sensitive Must SETI Arrays Be to Detect Extraterrestrial Signals?
- Canada Bob
- · Replies 3 ·
Undergrad Does the CMB reference frame violate the Cosmological Principle?
- smithpa9
- · Replies 7 ·
High School Can particles interact without a mass?
- nonamebrand
- · Replies 36 ·
High School Do Atoms Expand with the Universe?
- Tayler
- · Replies 76 ·
Undergrad Why does particle physics predict cosmo constant is 10^120 too big?
- swampwiz
- · Replies 13 ·
Undergrad N-body simulation of high or low-mass dark matter particles
- Ranku
- · Replies 4 ·
Undergrad Dark matter and structure formation
- Ranku
- · Replies 4 ·
Undergrad An apparently obscure question re dark matter
- Buzz Bloom
- · Replies 12 ·
Undergrad Is the supply of the observable CMB radiation limited?
- JimJCW
- · Replies 50 ·