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 What is Irradiance? Definition, Equations & Explanation
- Greg Bernhardt
- · Replies 1 ·
Graduate What are the effects of Hawking radiation on black holes?
- Greg Bernhardt
- · Replies 1 ·
Graduate What Describes the Expansion of the Universe?
- Greg Bernhardt
- · Replies 1 ·
Graduate What is the Friedmann acceleration equation
- Greg Bernhardt
- · Replies 1 ·
Graduate Frame Dragging: Definition & Equations
- Greg Bernhardt
- · Replies 1 ·
Graduate What is the Critical Density in the Context of Universe Expansion?
- Greg Bernhardt
- · Replies 1 ·
Graduate What Are Closed Timelike Curves in Black Holes?
- Greg Bernhardt
- · Replies 1 ·
Graduate What is Mass Inflation? A 5 Minute Introduction
- Greg Bernhardt
- · Replies 0 ·
Graduate How Does Binet's Equation Determine Acceleration in a Central Force Field?
- Greg Bernhardt
- · Replies 1 ·
Undergrad The Effect of Planets Rotation within its Galaxy?
- erickdt
- · Replies 3 ·
Undergrad Questions about the structure of the universe
- tolove
- · Replies 51 ·
Undergrad Astronomy Resources for Learning & Research
- Simfish
- · Replies 20 ·
Russia plans to leave International Space Station
- Greg Bernhardt
- · Replies 11 ·
Graduate Andromeda vs Milky Way dust emissions
- Chronos
- · Replies 1 ·
Graduate Initial conditions for tensor perturbations
- WannabeNewton
- · Replies 9 ·
Graduate The application of of Fermi Dirac statistics in the white dwarf
- clumps tim
- · Replies 2 ·
Graduate Gravity causing distances smaller than a Plack length?
- islaenningen
- · Replies 8 ·
Graduate Data on the Velocity of the Celestial Bodies Orbiting a Galaxy
- ecastro
- · Replies 3 ·
Graduate Holographic principle in reverse
- spenserf
- · Replies 3 ·
Undergrad How was the core temperature of sun estimated ?
- Murtuza Tipu
- · Replies 2 ·
Graduate Several questions regarding the nature of the universe
- Rysiu
- · Replies 2 ·
Undergrad Galactic Habitable Zone Theory: A Physiologist's Inquiry
- cbrons
- · Replies 7 ·
Graduate Can the Boltzmann equation accurately predict the relic density of dark matter?
- shahbaznihal
- · Replies 5 ·
Graduate Dark Energy/Matter: Why Does It Make Sense?
- kindlin
- · Replies 3 ·
Name Exoplanets: IAU Plans to Name 305 Exoplanets
- mfb
- · Replies 2 ·
Graduate Is there a "missing light crisis"?
- Dotini
- · Replies 7 ·
Graduate Traveling to Andromeda in 2 Months with a Spaceship
- LitleBang
- · Replies 3 ·
Graduate Is Redshift Only a Result of Universal Expansion?
- afcsimoes
- · Replies 9 ·
Graduate Conversion between density and column density
- bagherihan
- · Replies 1 ·
High School Do Objects in Space Float or Maintain a Fixed Position?
- Dylan Baker
- · Replies 2 ·
Undergrad Stopping a star from going supernova
- gtriafylos
- · Replies 3 ·
Graduate Lay-ish approach to *both* Friedman equations (2nd try)
- marcus
- · Replies 21 ·
Undergrad Could we read a newspaper from a satellite image?
- GTOM
- · Replies 10 ·
Graduate A speculative explanation why universe accelerates
- Ookke
- · Replies 16 ·
Graduate Is There a Maximum Distance Limit in Our Universe?
- vyas22
- · Replies 9 ·
Graduate Chandrashekhar paper on white dwarf
- clumps tim
- · Replies 3 ·
Graduate Questioning 3D Model views of effect of large bodies on curving space.
- MiguelCapelo
- · Replies 3 ·
Graduate Chandrashekhar limit for relativistic fermion gas
- cooper607
- · Replies 3 ·
Graduate How Do You Evaluate a Line of Sight Integral for Dark Matter Annihilation?
- majormuss
- · Replies 3 ·
Graduate Passing of time in Bolzmann's entropy curve. Is it all wrong?
- Paavo Palikka
- · Replies 2 ·
Undergrad Why can we see light emitted near the beginning of the universe?
- xazz
- · Replies 10 ·
Graduate Expansion, redshift, and conservation of energy
- TumblingDice
- · Replies 18 ·
Start planting trees on mars now
- howabout1337
- · Replies 22 ·
Graduate Does the Existence of the Axis of Evil Mean a Special Frame of Reference?
- DavidSnider
- · Replies 10 ·
Graduate Light Cone - Hubble Radius & Time T and R Relationship
- Ledsnyder
- · Replies 38 ·
Graduate What is "empty space" composed of?
- DiracPool
- · Replies 6 ·
Graduate Problem in Dodelson Modern Cosmology
- ChrisVer
- · Replies 3 ·
Graduate What Triggers a Supernova Explosion During a Star's Core Collapse?
- humk
- · Replies 6 ·
Graduate Big Dipper Cosmic Ray Hotspot Homogeneity question
- Tanelorn
- · Replies 5 ·
Graduate Solar System destroyed vs Supernova
- Easternwind
- · Replies 10 ·
Graduate Momentum transfer when object falls into black hole
- Ookke
- · Replies 5 ·
Is Intelligent Life in the Universe a Waste of Space?
- darrin016
- · Replies 22 ·
Graduate Why Do Io and Titan Exhibit Unique Surface Phenomena?
- scionkirk
- · Replies 1 ·
Graduate CMB cold spot explanation proposed (looks good)
- marcus
- · Replies 1 ·
Graduate Were the first stars much larger and shorter-lived than our sun?
- pforeman
- · Replies 3 ·
Graduate Expansion of Space vs Velocity in Space
- center o bass
- · Replies 17 ·
Graduate FRW cosmology [itex]Ω_{Λ}[/itex] domination
- ChrisVer
- · Replies 7 ·
Undergrad Are We Also Expanding with the Universe?
- ggolu2
- · Replies 7 ·
Moon occultation of Mars tonight
- Creator
- · Replies 4 ·
Graduate Why the Universe is accelerating as it is expanding
- Zero Ryoko
- · Replies 20 ·
Graduate How many infinite universes can fit within a multiverse?
- Athanasius
- · Replies 7 ·
Undergrad Hubble Finds Vast Reservoir of Gas Near Milky Way
- CygnusX-1
- · Replies 1 ·
Undergrad What is the basis of Rotation Curve?
- Lino
- · Replies 10 ·
Undergrad Understanding and Creating an O-C Diagram
- oliviam212
- · Replies 3 ·
Graduate Cosmology, Quantum fluctuations,and entanglement
- kw1
- · Replies 8 ·
Undergrad Is There a Simple Equation for Hubble's Constant and Time in Astronomy?
- Ledsnyder
- · Replies 2 ·
Graduate Why does A black hole need a massive center
- russinnj2000
- · Replies 7 ·
Graduate Are Wormholes Really Impossible Without Exotic Matter?
- cjackson
- · Replies 9 ·
Undergrad Why didn't the big bang just become a black hole?
- jaketodd
- · Replies 55 ·
Graduate Calculating the Density and Volume of Matter in the Expanding Universe
- bobie
- · Replies 16 ·
Graduate Decoupling condition for dark matter WIMP
- shahbaznihal
- · Replies 2 ·
High School Battery in Space? Current Flow in Vacuum?
- Shaun
- · Replies 8 ·
Graduate Chronology of recessional velocity
- yogi
- · Replies 4 ·
Undergrad Can the Sun's size affect the orbits of planets around it?
- enquirealways
- · Replies 13 ·
Graduate Why should the universe succumb to our measurments
- wolram
- · Replies 2 ·
Graduate Infinite Universe: What does it mean?
- zadignose
- · Replies 32 ·
Vale Bill Bradfield - The loss of a comet hunter
- davenn
- · Replies 2 ·
Graduate Trio of Big Black Holes Found in Galaxy Smashup
- CygnusX-1
- · Replies 11 ·
Graduate Discovering the Oldest and Most Distant Star: HD140283 Subgiant Star
- bobie
- · Replies 10 ·
Graduate Dark Energy: A Total Nuisance to Physicists?
- Aditya Vishwak
- · Replies 15 ·
Graduate Reason the early Universe was opaque?
- PeterPeter
- · Replies 4 ·
Graduate The Probability of an Infinite Universe
- Athanasius
- · Replies 19 ·
Graduate Size of Universe at CMB last Scattering
- zadignose
- · Replies 2 ·
Graduate Acceleration of Universe: Friedmann Equations
- Ledsnyder
- · Replies 7 ·
Graduate Proof of/Reason for SVT Decomposition
- AuraCrystal
- · Replies 1 ·
Undergrad Why do most galaxies have a flat, disc-like shape?
- bobie
- · Replies 6 ·
Undergrad Large Body Orbiting a Small One?
- Incognito310
- · Replies 15 ·
Does anyone know which paper that this figure come from?
- mhob
- · Replies 2 ·
Graduate Boundaries of Time in The Evolution of The Universe
- Quantizer
- · Replies 15 ·
Graduate Does the Block Universe Theory Suggest Time and Motion Are Illusions?
- enquirealways
- · Replies 6 ·
Graduate What is the relationship between the Hubble radius and the age of the universe?
- marcus
- · Replies 22 ·
Graduate How Can the Big Bang Occur Without Time?
- enquirealways
- · Replies 9 ·
Graduate Boltzmann equation for photons
- WannabeNewton
- · Replies 4 ·
Graduate Discover the Relationship Between CMB's Temperature and Redshift z in Cosmology
- Li Jiaxuan
- · Replies 9 ·
Graduate Was the expansion of the universe always greater than c?
- @Spuding102
- · Replies 20 ·
Graduate Scalar field in Expanding Universe EOM
- ChrisVer
- · Replies 13 ·
Graduate Couldn't the universe be finite if Omega =1?
- Athanasius
- · Replies 86 ·
Graduate Ratio of matter to radiation density
- Ranku
- · Replies 6 ·
Undergrad Will the Universe Shrink and Reignite Life?
- vrmuth
- · Replies 21 ·
Graduate Is dimensionless singularity truly dimensionless?
- No-where-man
- · Replies 70 ·