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 Far Can the Square Kilometre Array 'Listen' for Extraterrestrial Signals?
- alberto91
- · Replies 22 ·
High School Lithium problem in Big Bang nucleosynthesis?
- Aidyan
- · Replies 2 ·
Undergrad Do spinning neutron stars develop hollow cavities at their cores?
- Srb2001
- · Replies 9 ·
Graduate SPACE ROCKS: Latest meteorite into my collection
- davenn
- · Replies 3 ·
High School Meteor Storm Possible Thursday Night November 21-22
- websterling
- · Replies 5 ·
Graduate In the power spectrum, why is the peak frequency at the first harmonic
- dave gannon
- · Replies 5 ·
Undergrad Modeling a spiraling celestial body with calculus
- Gumbrain
- · Replies 4 ·
Graduate Steps on the way to Lightcone cosmological calculator
- marcus
- · Replies 86 ·
High School Why do we assume the big bang created matter/antimatter?
- physical
- · Replies 2 ·
Undergrad Can S5-HVS1 Retain Its Planets?
- DavidCummings
- · Replies 2 ·
Undergrad Clarifying the Meaning of Radius of Curvature in Cosmology
- Arman777
- · Replies 13 ·
Undergrad New measurement of the Hubble constant is consistent with the CMB value
- phyzguy
- · Replies 10 ·
Graduate Calculating the Gravitational wave spectrum with Inflation as a source
- shinobi20
- · Replies 3 ·
Graduate Missing step in the derivation of the Robertson-Walker metric
- Roy_1981
- · Replies 31 ·
Undergrad Why is there a difference between the composition of planets and stars?
- artis
- · Replies 28 ·
High School How constrained are the initial conditions of the universe?
- Quantum Alchemy
- · Replies 1 ·
High School Water found on potentially habitable exoplanet
- phinds
- · Replies 8 ·
Stargazing Mercury transit on November 11, 2019
- Andy Resnick
- · Replies 13 ·
Undergrad Cuspy halo problem in low-mass galaxies
- Arman777
- · Replies 5 ·
High School Will Big Stars Turn Into Red Supergiants or Red Giants?
- Odette
- · Replies 5 ·
High School Can you see a black hole head-on from outside its event horizon?
- PG1
- · Replies 19 ·
Undergrad Angular Momentum in a Solar Nebula
- Comeback City
- · Replies 7 ·
Undergrad Some questions related to the Cosmological Constant
- Arman777
- · Replies 4 ·
Undergrad CMBR and the expansion history of the Universe
- Ranku
- · Replies 2 ·
High School Are There Any Kardeshev 2.0 Civilizations in the Milky Way?
- stefan r
- · Replies 19 ·
High School How well do we know solar activity?
- Skiessa
- · Replies 3 ·
High School Milky Way is "in the top percentile of all the galaxies that exist"
- CygnusX-1
- · Replies 29 ·
Undergrad What does the cosmic inflation theory actually say about flatness?
- overzealous
- · Replies 9 ·
High School Name for the distribution of matter?
- Brian Turner
- · Replies 5 ·
High School Structure and Dynamics of Blue Supergiants
- lavinia
- · Replies 2 ·
High School Universe expansion rate in m/s^2 ?
- roineust
- · Replies 20 ·
High School We see a quasar 13 billion light years away. What does this mean?
- Skiessa
- · Replies 4 ·
Undergrad What is the new source of space radiation discovered near Earth?
- davenn
- · Replies 46 ·
Undergrad Where does gravity switch from stronger to weaker, if it does?
- freeelectron
- · Replies 7 ·
Graduate What does "space gives moving orders" mean for gravity?
- Boballoo
- · Replies 5 ·
Undergrad Does flat spacetime geometry prove the universe is infinite?
- Ehyeh Asher Ehyeh
- · Replies 9 ·
Undergrad The Multiverse and 'No boundary' conditions approach in cosmology
- Suekdccia
- · Replies 3 ·
High School Hip Replacements and Weather Sensitivity
- wolram
- · Replies 6 ·
High School What Are the Force and Speed of Pulsar Winds?
- Sundown444
- · Replies 19 ·
Undergrad Interpreting a scale factor vs. distance graph
- naushaan
- · Replies 13 ·
Undergrad Separating Masses in Kepler's Third Law
- KireeDendrall
- · Replies 1 ·
High School The search for habitable exoplanets in Alpha Centauri
- alberto91
- · Replies 2 ·
Undergrad Confusion over what exactly constitutes the ecliptic
- thebosonbreaker
- · Replies 3 ·
Undergrad Mass-luminosity relationship for red giants and AGB stars?
- tovisonnenberg
- · Replies 1 ·
Graduate Resources for retrograde satellite orbit stability and resonance
- mollwollfumble
- · Replies 5 ·
Undergrad Dark matter distribution and Milky Way rotation curve constraints
- KurtLudwig
- · Replies 14 ·
Undergrad Was the Early Universe as Dense and Hot as a Neutron Star?
- Greta
- · Replies 24 ·
Undergrad Calculating Speed and Acceleration of a Gas Blob Orbiting a Massive Black Hole
- naushaan
- · Replies 4 ·
High School Why does the moon orbit Earth instead of the Sun?
- Evenlander
- · Replies 8 ·
Undergrad Would a rover on an asteroid float away because of the low gravity?
- sciencec
- · Replies 7 ·
Undergrad Does Euclidean geometry require initial fine-tuning?
- timmdeeg
- · Replies 19 ·
Undergrad How is asteroid 101955 Bennu possible?
- alva3
- · Replies 8 ·
High School What is the shape of an asteroid impact on Earth?
- Evenlander
- · Replies 3 ·
Friday's Historic All-Woman Spacewalk
- Greg Bernhardt
- · Replies 2 ·
High School Will dropping dust grains in a box with a lightbulb simulate interstellar dust?
- angela6884
- · Replies 13 ·
Undergrad What happens to gravitational waves?
- StandardsGuy
- · Replies 28 ·
Undergrad Lambda CDM Model and Spatial Flatness
- timmdeeg
- · Replies 26 ·
Graduate Effects of gravity throughout space-time?
- TrentonF
- · Replies 6 ·
Undergrad Speed and distance for Mars-to-Earth travel in 104 days, February-June 1901
- vicvalis
- · Replies 10 ·
Undergrad Maximum ##d_p(t_e)## value and its meaning
- Arman777
- · Replies 2 ·
Undergrad How can black holes with varying masses have the same extreme characteristics?
- Soul Intent
- · Replies 10 ·
High School Why does the Andromeda galaxy appear so tiny from our perspective?
- Dnj23
- · Replies 81 ·
Undergrad Heating/cooling moon tunnels, why and how?
- Fred Bobo
- · Replies 16 ·
High School Anyone here in the CA blackout area that has enjoyed dark skies?
- swampwiz
- · Replies 6 ·
Undergrad Matter-Antimatter black hole collision
- wheyghey
- · Replies 4 ·
Undergrad Does a galaxy's recessional velocity increase its mass in special relativity?
- Arman777
- · Replies 3 ·
Undergrad Does 'space itself expanding' arise from choice of coordinates?
- michelcolman
- · Replies 27 ·
Undergrad Are the red dots in the Whirlpool Galaxy individual red supergiants?
- swampwiz
- · Replies 2 ·
Undergrad Scale factor from Friedmann's equations
- TheMercury79
- · Replies 7 ·
Graduate Late Photons from the Early Universe?
- Benzij
- · Replies 1 ·
High School What parameters of physics are most important to the existence of life?
- Suppaman
- · Replies 29 ·
High School Was the 1995 exoplanet discovery worthy of the Nobel Prize?
- bland
- · Replies 6 ·
Graduate Why isn't back-reaction receiving more study?
- phyzguy
- · Replies 18 ·
High School Atoms, Black Holes: Solving 2 Problems with 1 Theory?
- tony169
- · Replies 4 ·
High School Angular Meteorite Strikes on the Moons Surface
- Clay Gillespie
- · Replies 2 ·
Undergrad What is the current state of research on the nature of Time?
- samudra
- · Replies 13 ·
Undergrad How to Assign Initial Conditions for Binary Star Systems in a Simulation?
- Arman777
- · Replies 2 ·
High School What Happens to a Dead Galaxy's Mass?
- brand1130
- · Replies 15 ·
Undergrad How Does Kirchoff's Law Relate to Spectrum Intensity and Wavelength?
- SebastianRM
- · Replies 8 ·
Undergrad Hubble relation to Scale Factor
- TheMercury79
- · Replies 3 ·
High School Was the universe in a pure state during the Planck epoch?
- Quantum Alchemy
- · Replies 1 ·
High School Do electrons orbit nuclei in stars, or do they float freely?
- PhDnotForMe
- · Replies 9 ·
Undergrad Is Planet 9 Actually a Primordial Black Hole?
- Tom.G
- · Replies 6 ·
Undergrad Can radiation pressure account for cosmic expansion?
- AshPowers
- · Replies 6 ·
Undergrad How does BBT resolve away from "It should be a black hole"
- AshPowers
- · Replies 2 ·
Undergrad How can Kepler's laws be visualized using a simulator?
- Riverplatense
- · Replies 1 ·
Undergrad How do we measure galactic rotation and confirm dark matter?
- PhDnotForMe
- · Replies 5 ·
Undergrad NASA's Black Hole Visualization/Explanation
- BillTre
- · Replies 13 ·
Undergrad Does a beginning to time imply absolute speed?
- Hiero
- · Replies 8 ·
High School Is there more to the Red Shift than we think?
- jeffinbath
- · Replies 18 ·
Graduate What's the Difference Between Gravitational Waves and Gravity Waves?
- math04
- · Replies 1 ·
Undergrad Could fundamental laws change in Dirac's Large Numbers Hypothesis?
- Suekdccia
- · Replies 1 ·
High School Superclusters and their galaxies
- Powehi
- · Replies 3 ·
Undergrad Cross sections of dark matter particle candidates
- Arman777
- · Replies 7 ·
High School Can we expand space in a laboratory?
- Suppaman
- · Replies 10 ·
Possible to build a space tower?
- skyshrimp
- · Replies 28 ·
Stargazing Who Tracks and Warns Us About Asteroids?
- RetailPleb
- · Replies 9 ·
Anyone else thought the Moon last night was cool?
- HankDorsett
- · Replies 19 ·
Undergrad Is J0740+6620 an eclipsing system?
- GeorgeDishman
- · Replies 2 ·
Stargazing What explains the Luna impact gap?
- Gfellow
- · Replies 33 ·