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
Graduate Equation involving H and a re Accerlerating Universe
- Buzz Bloom
- · Replies 8 ·
Undergrad Difference between a red giant and red supergiant?
- 21joanna12
- · Replies 4 ·
Graduate Stefan-Boltzmann law, luminosity, brightness and magnitude?
- 21joanna12
- · Replies 2 ·
Graduate Why do toddlers have a logarithmic understanding of numbers?
- Petahanks
- · Replies 11 ·
Undergrad Was Space Present Before the Big Bang?
- tressure
- · Replies 13 ·
Undergrad SDP.81 : how do we see the gavitational lens?
- maajdl
- · Replies 2 ·
Undergrad Time Theory in Astrophysics: How Is It Possible?
- Hunter Brandon
- · Replies 13 ·
Graduate Are atomic energies increasing as the Universe expands?
- jcap
- · Replies 2 ·
Undergrad Question About Gravitational Time Dilation
- RM Isco
- · Replies 3 ·
Favorite Prominent / Professional Astrophotographers
- excelsior
- · Replies 2 ·
Graduate Did the universe have a begining?
- wolram
- · Replies 9 ·
Graduate How is Dark Energy Density Calculated in the Universe?
- Quarlep
- · Replies 16 ·
High School Does space-time have an energy itself?
- Quarlep
- · Replies 59 ·
Graduate Death of Sun: Habitable Zone & Timeline
- JohnPrior3
- · Replies 8 ·
Graduate Should the concept of Falsifiability be abandoned in science?
- wolram
- · Replies 22 ·
Graduate Why are there stars that are "older than the universe"?
- jack476
- · Replies 4 ·
Graduate Cosmological vs. Relativistic Doppler Shift
- thrush
- · Replies 4 ·
Undergrad Doubt About Hour Angle: How Can It Change So Little?
- Frank Einstein
- · Replies 4 ·
High School Constant acceleration of gravity
- quincy harman
- · Replies 2 ·
Graduate When did relic neutrinos cease being relativistic?
- GeorgeDishman
- · Replies 4 ·
High School Understanding Gravitational Pull and Its Effects on Humans
- yuganes warman
- · Replies 12 ·
Graduate Galaxy Merger Energy: Calculating Total System Energy
- jl29488
- · Replies 8 ·
Graduate Explanation for similar structures at different scales
- Jimster41
- · Replies 2 ·
Undergrad Understanding Big R(t) in Astronomy: A Physical Perspective
- scoopaloop
- · Replies 7 ·
Graduate Is Dark Energy a Misinterpreted Phenomenon?
- Allan R.
- · Replies 10 ·
Graduate Julian Ephemeris Date from Ephemeris Time
- Philosophaie
- · Replies 1 ·
Undergrad What's the nothingness that our universe is expanding into?
- Meron
- · Replies 76 ·
Graduate Gravitational entropy in the early universe
- Khashishi
- · Replies 7 ·
Graduate What is the relationship between orbital semi latus rectum and angular momentum?
- Penguinluons
- · Replies 3 ·
Undergrad Why does the Sun behave like a black body?
- resurgance2001
- · Replies 32 ·
Graduate Bending of space and time, is it true?
- AshUchiha
- · Replies 71 ·
Graduate How Can We Harness the Power of Space Elevators and Atmospheric Electricity?
- Mk
- · Replies 7 ·
Graduate Black holes in the globular cluster M22 with Dr. Tom Maccarone
- liometopum
- · Replies 12 ·
Graduate Calculating Surface Density of the Universe Using the Shell Model
- Quarlep
- · Replies 7 ·
Undergrad Friedmann's Assumption: Understanding the Universe's Uniformity
- pvk21
- · Replies 44 ·
High School Planetary Alignment: Mercury Out of Sync
- Frank Einstein
- · Replies 12 ·
Graduate Size of observable vs UN-observable Universe, etc
- Stan Stuchinski
- · Replies 3 ·
Graduate What can you learn about cosmology from Google calculator?
- marcus
- · Replies 111 ·
Stargazing Is this a realistic design for a kilometer wide telescope?
- RKOwens
- · Replies 14 ·
Graduate Scientific importance of total Solar eclipses?
- tarquinius
- · Replies 10 ·
Graduate The Potential of Titan: Igniting Methane Oceans for Photosynthesis
- bennyschmidt
- · Replies 34 ·
High School Do we all belong to the same star?
- Yashbhatt
- · Replies 7 ·
Graduate Role of quantum mechanics in cosmology
- pvk21
- · Replies 11 ·
Graduate Latest News from the Universe: CDM vs WDM and the Future of Dark Matter Models
- wolram
- · Replies 5 ·
Graduate Boltzmann equation Kinetic equilibrium (Dodelson)
- center o bass
- · Replies 1 ·
Undergrad Proof to Kepler's first and second laws
- Shahar
- · Replies 3 ·
Graduate Analogy for recession of galaxies > the speed of light
- osotou
- · Replies 8 ·
Stargazing Understanding reflecting telescopes?
- 21joanna12
- · Replies 6 ·
Undergrad How wide is the observable horizon, at sea level?
- Lonious
- · Replies 10 ·
Graduate High redshift galaxies in the HUDF
- sketos
- · Replies 1 ·
Graduate Fundamental Relationship Between Time and Space Derivatives
- ElectricKitchen
- · Replies 6 ·
Undergrad What is the center of a globular clusters made of?
- vrmuth
- · Replies 50 ·
Graduate Forming Stars: 2 Conditions and Criteria Explained
- thegirl
- · Replies 5 ·
Graduate Our universe as an expanding sponge that is constantly falling.
- Shu Sheng
- · Replies 6 ·
Graduate Do M or string theory imply a lower limit to size?
- slatts
- · Replies 4 ·
Graduate Classifying Exoplanets: Size & Surface Temperature
- lpetrich
- · Replies 6 ·
Undergrad How Can We Reach Habitable Exoplanets?
- cjackson
- · Replies 8 ·
Graduate Supernova prediction: SN Refsdal
- mfb
- · Replies 1 ·
Undergrad Exoplanet Eccentricity vs Orbital Period
- Drakkith
- · Replies 5 ·
Undergrad Saturn Day Shorter Than Expected | Ken Croswell | Science
- CygnusX-1
- · Replies 4 ·
Is the Hubble Telescope Smiling at a Gravitational Lens?
- Andy Resnick
- · Replies 12 ·
Stargazing How Do Lasers Work in Telescopes to Capture Images of the Universe?
- pvk21
- · Replies 3 ·
High School Fake magnification and other information
- sauroman1
- · Replies 6 ·
Graduate Redshift of supernova light curve
- jcap
- · Replies 10 ·
Stargazing Understanding the Field of View of Reflecting and Refracting Telescopes
- 21joanna12
- · Replies 9 ·
Graduate Question on possible dark matter classification
- aademarco
- · Replies 9 ·
Undergrad Question about spectral lines of stars?
- 21joanna12
- · Replies 3 ·
Graduate Feedback and equilibrium between black holes and galaxies
- Tanelorn
- · Replies 4 ·
Graduate How can you show the CMB shift parameter?
- shadi_s10
- · Replies 7 ·
I got a bad feelin' about this Chewie turn us around
- DaveC426913
- · Replies 4 ·
Stargazing Quick question about telescope classification
- 21joanna12
- · Replies 3 ·
Graduate Covariance betw scalar amplitude & spectral index in Planck?
- thecommexokid
- · Replies 2 ·
Graduate Black Holes & Galaxies: How Do They Work Together?
- twisted-outcast
- · Replies 3 ·
Graduate Why is vacuum energy 10^100 times larger than the cosmological constant?
- Quarlep
- · Replies 5 ·
Graduate What does a temporally infinite universe imply?
- slatts
- · Replies 1 ·
Graduate Could a Collapsing Black Hole Be the Origin of Our Universe?
- Shu Sheng
- · Replies 9 ·
Stargazing Viewing stars through a refracting telescope?
- 21joanna12
- · Replies 2 ·
High School Are Jupiter's bands visible with binoculars?
- Glenstr
- · Replies 17 ·
Graduate What supported the singularity during the Big Bang?
- Bray420
- · Replies 7 ·
How Did I Capture Orion and Comet Lovejoy in Arizona?
- spark802
- · Replies 4 ·
Undergrad Why is the universe considered to be flat?
- Meron
- · Replies 3 ·
Graduate Supernova Explosion near a black hole
- Ravi Prakash
- · Replies 7 ·
High School Measuring Light Years: How Far Is the Andromeda Galaxy?
- JustATheory
- · Replies 3 ·
Graduate Entire universe ending with a supermassive black hole?
- Shu Sheng
- · Replies 10 ·
Graduate Static universe, spacetime and the stress-energy tensor
- timmdeeg
- · Replies 13 ·
Undergrad Please explain the statement "the big bang happened everywhere at once"
- CaptDude
- · Replies 154 ·
Graduate How do scientists estimate the total energy of the universe?
- Quarlep
- · Replies 15 ·
Graduate What are Branes? Explained Simply
- Quds Akbar
- · Replies 5 ·
Graduate Dark energy and the Cosmological Constant
- Quds Akbar
- · Replies 37 ·
Did You Capture the March 17 Aurora Borealis?
- spark802
- · Replies 2 ·
Graduate Eccentric & Mean Anomaly: Difference & Drawing
- Philosophaie
- · Replies 2 ·
What Is the Significance of the Solar Eclipse on March 20, 2015?
- Garth
- · Replies 13 ·
Feeling insignificant after watching space movies
- HomogenousCow
- · Replies 10 ·
Undergrad Multiple universes: Nothing more than philosophising?
- richard9678
- · Replies 46 ·
Undergrad Why are the more distant galaxies/stars moving faster away?
- Kiyal
- · Replies 29 ·
High School Can someone explain what it is meant by a 'Flat Universe'?
- Kiyal
- · Replies 25 ·
Amazing shot of a meteor over Loch Ness
- Greg Bernhardt
- · Replies 6 ·
Graduate Tidal lock and landmass on a Earth-like planet
- Czcibor
- · Replies 1 ·
Graduate How do we know Inflation begin in 10^-35 second?
- Quarlep
- · Replies 3 ·
Meteor trajectories -- Interested in computing them?
- solarblast
- · Replies 4 ·