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
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 ·
Graduate Could Hubble tension be a measurement artifact from underestimated uncertainties?
- ritesh
- · Replies 6 ·
High School What is the Maximum Mass of a Neutron Star?
- Grinkle
- · Replies 4 ·
High School Why are massive black holes harder to observe than expected?
- Astronuc
- · Replies 4 ·
Undergrad Is the Sun a low-mass star or a medium-mass star?
- xoxo1001
- · Replies 7 ·
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 Where are the ices in Jupiter and Saturn's composition?
- 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 Course adjustments needed as a starship approaches its destination star
- 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 Measuring Venus transit parallax in Stellarium from different locations
- 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 Why does the Moon's declination appear larger than its maximum from Earth?
- 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 Orion 130 reflector has very narrow field of view
- 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 Can an infinite universe be cyclic if infinite matter must contract to a point?
- TheHeraclitus
- · Replies 1 ·
High School Acceleration of time due to entropy
- R0dr1go
- · Replies 1 ·
High School CMB photons: relics from the early universe or from recombination?
- 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 Self-publishing a cosmology book as an amateur astronomer
- 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 Does gravitational force vary with position in the solar system?
- 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 Could collisions with the proto-Sun have formed 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 Strange objects near Orion in Aladin sky survey
- Hijole
- · Replies 10 ·
Undergrad Evidence for existence of a 9th Planet in the solar system
- Zeeshan Ahmad
- · Replies 15 ·
Graduate Sum of chi-squared with ell-dependent variances into single chi-squared
- 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 Why is a monolithic Dyson sphere impossible?
- HystereeSis
- · Replies 3 ·
Undergrad Why is dark matter preferred over modifying gravity?
- 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 ·