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 Amaterasu and GRB221009A: A Comparison of Cosmic Rays and Gamma Ray Bursts
- paulalex7000
- · Replies 5 ·
High School More Experimental Evidence for MOND
- jedishrfu
- · Replies 119 ·
Undergrad Why didn't the Big Bang form a Black Hole?
- peterraymond
- · Replies 7 ·
Undergrad Why Does NASA Claim 10-100x Better Bandwidth from Optical Communications?
- berkeman
- · Replies 14 ·
Undergrad What does the output of a radio telescope look like?
- accdd
- · Replies 3 ·
Stargazing Has a Deep Field Picture of the Sky Been Captured with a Radio Telescope?
- zuz
- · Replies 5 ·
Undergrad More extended equilibrium configurations due to dark energy?
- Suekdccia
- · Replies 19 ·
High School How to calculate Aphelion distance?
- Mikael17
- · Replies 14 ·
High School What keeps most galactic stars from falling into the centeral black hole?
- KurtLudwig
- · Replies 6 ·
High School How Do We Calculate the Number of Atoms in the Universe?
- zaman786
- · Replies 7 ·
Undergrad Is Dark Matter the Key to Understanding the Pre-Visible Universe?
- Low Mass Star
- · Replies 5 ·
Undergrad Can You Build Your Own Radio Telescope at Home?
- Tom.G
- · Replies 3 ·
High School Visible Light Through a Wormhole
- bzcle316
- · Replies 2 ·
High School First light from the Euclid telescope
- Filip Larsen
- · Replies 4 ·
Undergrad Question on multiple rebrightening gamma ray bursts and gravity waves
- Sware
- · Replies 9 ·
Undergrad Telling time on Iapetus and other general questions about Iapetus
- DiamondTiara
- · Replies 13 ·
Graduate Convention of units for densities in cosmology
- fab13
- · Replies 0 ·
Undergrad Dark Energy contribution to plasma temperature in galaxy clusters?
- Suekdccia
- · Replies 7 ·
Undergrad An asteroid the size of the Rose Bowl has a slight chance of impacting Earth?
- zuz
- · Replies 14 ·
Undergrad Solar Calendar -- When was the leap day inserted?
- ethan2
- · Replies 7 ·
Undergrad How Can We Measure Properties of Distant Planets and Stars?
- Hak
- · Replies 12 ·
Undergrad Nuclear reactions in the Sun and other topics on stars
- Hak
- · Replies 49 ·
Undergrad Formation of emission lines and other topics
- Hak
- · Replies 5 ·
Undergrad Star cluster in the Milky Way appears to be as old as the Universe
- Tom.G
- · Replies 11 ·
Undergrad Is Tipler's Theory of Immortality Worth Considering Without Religious Bias?
- James William Hall
- · Replies 15 ·
Undergrad Big bang occuring everywhere vs everything "compressed"
- Martyn Arthur
- · Replies 16 ·
High School Does the Universe prefer certain kinds of matter based on the laws in place?
- LightningInAJar
- · Replies 19 ·
Undergrad Using GR to predict the shape of the entire universe?
- Feynstein100
- · Replies 24 ·
Undergrad How does gravitational self-interaction affect the Milky Way Galaxy?
- KurtLudwig
- · Replies 3 ·
Undergrad Understanding Space-Time Expansion: Debunking the Myth of Non-Physical Space
- PhanthomJay
- · Replies 15 ·
High School What value of z (redshift) equals apparent superluminal recession?
- Cerenkov
- · Replies 28 ·
Undergrad Limitations of Observing Distant Space Objects
- laith salim
- · Replies 38 ·
High School Can Jupiter gravitationally eject a pebble in orbit? A smaller mass?
- syfry
- · Replies 2 ·
High School Supernova Ejection: How Large Are the Chunks?
- pforeman
- · Replies 14 ·
Undergrad Is it possible to build a Telescope the Size of Half the Solar System size using all Lagrange Points?
- Mukhtar
- · Replies 6 ·
Graduate Save Time with CLASS Code: Neat Trick for Background Quantity Evolution
- tsaic2808
- · Replies 0 ·
Stargazing Understanding the Formula for Sunrise and Sunset Calculation
- VansFannel
- · Replies 11 ·
Undergrad Tidal effects of galaxies orbiting one another with dark energy?
- Suekdccia
- · Replies 2 ·
Stargazing How can we be sure that Leavitt’s law works?
- Juju_114
- · Replies 16 ·
High School Annular eclipse October 14, 2023
- gmax137
- · Replies 3 ·
Undergrad Why Is a Flat Universe Infinite?
- albie
- · Replies 56 ·
Undergrad What are P03 procedures or guidelines?
- Old Person
- · Replies 3 ·
High School Roger Penrose model of the rebirthing universe
- rolnor
- · Replies 16 ·
High School How did expansion take 380,000 years to let light travel freely?
- syfry
- · Replies 13 ·
Undergrad Cosmological expansion of space - question
- elcaro
- · Replies 3 ·
High School Can anyone suggest a good website to buy astronomy equipment?
- LightningInAJar
- · Replies 6 ·
High School Which star is the closest red giant to Earth according to The Guardian?
- Vanadium 50
- · Replies 32 ·
High School Is the existence of Planet 9 supported by Modified Newtonian Dynamics?
- wolram
- · Replies 16 ·
Undergrad “Interpreting astronomical spectra” -- Continuum origins
- Getterdog
- · Replies 29 ·
Undergrad Same state as in the Big Bang in a collapsing universe?
- Suekdccia
- · Replies 2 ·
Undergrad Effects of gravity on planetary core structure
- cusz721
- · Replies 9 ·
High School Am I attracted to a hydrogen atom 1 billion light years away?
- jeff einstein
- · Replies 9 ·
Undergrad Location of the magnetopause using Chapman-Ferraro equation
- Kovac
- · Replies 16 ·
Graduate NASA's DART spaceship has hit the Dimorphos asteroid: what now?
- OscarCP
- · Replies 4 ·
Undergrad Dark energy contributing to, or modifying, mass estimates?
- Suekdccia
- · Replies 1 ·
Graduate Why the James Webb Space Telescope needs propellant
- James Demers
- · Replies 2 ·
High School Why Does an Einstein Ring Have Four Images?
- DaveC426913
- · Replies 9 ·
High School Difference between autumnal and vernal equinoxes
- MrEbola
- · Replies 13 ·
High School The distance to the nearest identical Hubble volume in light years?
- Cerenkov
- · Replies 50 ·
Undergrad Resolution of observation telescopes?
- LightningInAJar
- · Replies 3 ·
Undergrad Can astronomical observation take place in daylight in Antacrtica?
- swampwiz
- · Replies 6 ·
Graduate Poisson noise on ##a_{\ell m}## complex number: real or complex?
- fab13
- · Replies 0 ·
Undergrad What was expansion speed at the time of the CMB?
- sjordannc
- · Replies 3 ·
Undergrad Is El Gordo's Collision Velocity Challenging ΛCDM?
- pinball1970
- · Replies 0 ·
High School SubNeptune planet K2-18b shows methane and dimethyl sulfide
- DaveC426913
- · Replies 3 ·
High School Questions about relative Space-Time in the Universe
- WesKnight
- · Replies 24 ·
Undergrad Doubts about isotropy of space
- gionole
- · Replies 23 ·
Undergrad Surely the 2nd Law of Thermodynamics is defied by gravity?
- jeffinbath
- · Replies 11 ·
Undergrad Working model to demonstrate Lagrange points L4 & L5 -- possible?
- Swamp Thing
- · Replies 4 ·
High School Why is spacetime shown on a 2 dimensional plane?
- Crazyhorse2882
- · Replies 28 ·
Undergrad The boundary conditions at infinity
- Jaime Rudas
- · Replies 41 ·
Undergrad Formation of rocky planets without a star
- Mechanochemist
- · Replies 18 ·
High School Do changes in speed always affect orbit size, and vice versa?
- syfry
- · Replies 30 ·
Undergrad Unobservable Universe and the CMBR
- PhanthomJay
- · Replies 22 ·
Undergrad Formation of jets with accretion disks at black holes
- haushofer
- · Replies 11 ·
Undergrad Inquiry Regarding the Determination of the Galactic Disk's Outer Bound
- MountKobau
- · Replies 6 ·
Undergrad Why Didn't Henrietta Leavitt Sign Her Own Discovery Paper?
- Jaime Rudas
- · Replies 16 ·
High School A Question about Cosmic Background Noise
- dom_quixote
- · Replies 13 ·
Undergrad Would there be any way to avoid gravitational wave emissions?
- Suekdccia
- · Replies 4 ·
Undergrad Role of Dark Matter in the Evolution of Large Scale Structure
- hkyriazi
- · Replies 9 ·
Undergrad Comparing the formation of the atmospheres on Earth vs Venus
- stuartmacg
- · Replies 1 ·
High School More Evidence for MOND -- Globular cluster galactic acceleration imprint
- ohwilleke
- · Replies 1 ·
Undergrad Does the Cosmological Principle in any way underpin Big Bang Theory?
- hkyriazi
- · Replies 33 ·
Undergrad "Quasar clocks" and time running slower long ago
- hkyriazi
- · Replies 9 ·
Undergrad The theoretical basis for a hot Big Bang?
- hkyriazi
- · Replies 7 ·
Undergrad Seeking Visualization Tools for Hypothetical Black Hole Concept
- andrefff1
- · Replies 2 ·
Undergrad Ancient galaxies: lack of mergers vs. subsequent spatial expansion
- hkyriazi
- · Replies 5 ·
Undergrad Obtaining Transit Spectrum for Celestial Bodies Using JWST NIRSPEC
- starryexplorer
- · Replies 3 ·
Graduate How to convert mW/m^2 to W/m^2/nm?
- AdrianD
- · Replies 11 ·
Undergrad Cosmological red shift and cosmic time dilation
- andrew s 1905
- · Replies 6 ·
Undergrad What is the accuracy of parking spacecraft into Lagrange points?
- RobbyQ
- · Replies 9 ·
Undergrad Entropy reversal in an infinite static universe?
- Suekdccia
- · Replies 1 ·
Undergrad Longest day of the year is June 21 but longest daylight is June 26?
- gary350
- · Replies 4 ·
High School What does it mean to say the Universe is the same everywhere?
- bahamagreen
- · Replies 8 ·
Graduate Advice needed for exposure time computation for galaxies
- AdrianD
- · Replies 2 ·
Undergrad DeSitter cosmological horizon stability?
- Suekdccia
- · Replies 3 ·
Undergrad Anyone know about the bolide across the Gulf Coast Fri July 14, 2023?
- swampwiz
- · Replies 1 ·
Undergrad Could entropy be reversed eventually in the far future?
- Suekdccia
- · Replies 9 ·
Undergrad Error in Euler angles and quaternions
- jonagad
- · Replies 1 ·
High School How can a single Big Bang be true?
- Joshua10
- · Replies 20 ·