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 How certain is the universe flat, and what would cause the big crunch?
- Chemist@
- · Replies 119 ·
Undergrad Is there a place in the Universe without any matter and energy?
- gen6
- · Replies 12 ·
Graduate What does surface density mean for circumstellar disks?
- robotopia
- · Replies 6 ·
High School Is Earth Orbiting the Sun Dynamically?
- syrf3763
- · Replies 8 ·
High School Why Does the Sun Bob Up and Down in its Orbit?
- enceladus_
- · Replies 28 ·
Graduate Can Energy exist with the absence of matter?
- Ayham
- · Replies 2 ·
Graduate It's a rate (not a constant) so let's call it that
- marcus
- · Replies 8 ·
Graduate Why are galaxies flat when a rotating mass pulls on nearby objects?
- tolove
- · Replies 9 ·
High School Is Constant Rest Possible in Outer Space?
- MathematicalPhysicist
- · Replies 2 ·
Graduate Could the Big Bang Have Been a Massive Black Hole Eruption?
- Randomtask94
- · Replies 17 ·
Graduate Black hole growth and evaporation
- egcavalcanti
- · Replies 2 ·
Graduate Are Statistical Mechanics Adequate for Interstellar and Intergalactic Clouds?
- anorlunda
- · Replies 3 ·
Graduate Nature of spacetime and interest in the field
- Macrobe
- · Replies 1 ·
Graduate What happened to the dark matter discovery announcement from February?
- DiracPool
- · Replies 13 ·
Graduate What is the relationship between light and space?
- Seminole Boy
- · Replies 7 ·
Graduate Which Planck numbers to use? (Ned Wright's choice?)
- marcus
- · Replies 10 ·
Graduate Kudo list of well-written exchanges for the month of April :-D
- marcus
- · Replies 0 ·
Graduate Thoughts/Questions about GR and dark matter
- DLH112
- · Replies 3 ·
Graduate Would Dark Energy Alter Layzer's Entropy Model?
- j1mcross
- · Replies 8 ·
Graduate Why doesn't dark matter clump together?
- mrspeedybob
- · Replies 1 ·
High School Why Do We Search for Exoplanets?
- wolram
- · Replies 20 ·
Graduate Formula for the dark energy density (dark energy formula)
- Alexroma
- · Replies 5 ·
Graduate Galaxy classification survey from cosmological simulations
- wmfw23
- · Replies 3 ·
Graduate Observational problems with the expanding universe theory
- dm4b
- · Replies 13 ·
Graduate Redshift at 11.9 and the Hubble Constant
- phtdegroot
- · Replies 11 ·
Graduate Is it wrong to see the bang as insertion of space?
- negativzero
- · Replies 8 ·
Undergrad Are there any large star databases containing mass and density?
- Xilor
- · Replies 4 ·
Graduate What is the TSS Engine and how can it enhance space-related learning?
- Kirennian
- · Replies 6 ·
Graduate How can we say star mass affects event horizon diameter ?
- PhyHunter
- · Replies 5 ·
Graduate Cosmological redshift, how fast can the universe expand?
- P.Bo
- · Replies 16 ·
Graduate Given expansion, finally each particle will have only 1 neighbor
- negativzero
- · Replies 10 ·
Graduate Why Stephen Hawking says universe can create itself from nothing?
- big_bounce
- · Replies 81 ·
Graduate Singularity Paradoxes: Nothing or Something?
- jerryboy
- · Replies 4 ·
Undergrad What Is Space in Physics?
- tolove
- · Replies 30 ·
Graduate Did Quasars Play a Role in the Formation of Galaxies?
- SpiderET
- · Replies 17 ·
Conspiratorial cosmology - the case against the Universe
- Garth
- · Replies 1 ·
Undergrad The time it takes the Earth to go around the Sun.
- Jimmy B
- · Replies 49 ·
Graduate When Will the Big Crunch Happen According to Current Models?
- Devils
- · Replies 37 ·
Undergrad Why do cosmic rays and hard X-rays heat molecular clouds while soft X-rays don't?
- vikasagartha
- · Replies 2 ·
Redshift FAQ article development
- Mordred
- · Replies 142 ·
Graduate Why do distant galaxies look different if inflation made the observable universe tiny?
- HowardTheDuck
- · Replies 12 ·
Undergrad How big was the Universe 13 billion years ago?
- Endervhar
- · Replies 41 ·
Graduate Why does dark energy repel if it has mass and curves spacetime?
- Robin
- · Replies 5 ·
High School Can we treat Earth as stationary and the sun as orbiting it?
- jackoblacko
- · Replies 91 ·
Graduate HR diagram: magnitude - luminosity relation
- stargazer3
- · Replies 3 ·
High School How does the sun burn without oxygen?
- Anna Blanksch
- · Replies 5 ·
Graduate Gravitational Acceleration Differences in a Pulsar: Calculation and Comparison
- wcase
- · Replies 4 ·
Graduate Decent papers/articles on black holes
- abhiroop_k
- · Replies 4 ·
Graduate Trying to understand the oscillation of electrons in the magnetic fiel
- hb1547
- · Replies 5 ·
Graduate How did the CMB Lorentz frame get chosen?
- Sam_Playle
- · Replies 5 ·
Graduate Does the boundary of the causal universe function as an event horizon?
- benlittle
- · Replies 18 ·
Undergrad Cosmological constant calculation
- ftr
- · Replies 5 ·
Graduate Higgs/vacuum stability and the universe
- skydivephil
- · Replies 2 ·
Graduate Are WIMPs bosons or fermions?
- snorkack
- · Replies 1 ·
Graduate Schwarzschild radius for cosmological expansion vs black holes
- liometopum
- · Replies 2 ·
Undergrad How should I see the CMB picture
- the_pulp
- · Replies 3 ·
Graduate A Gravitational Entropy proposal from Ellis, Tavakol, and Clifton
- marcus
- · Replies 1 ·
Graduate Problems with living outside the Heliosphere?
- StrayCatalyst
- · Replies 1 ·
Graduate Possible reason for dark energy (?)
- jacjac
- · Replies 16 ·
Graduate What slowed or stopped inflation?
- abbott287
- · Replies 15 ·
Graduate Article on New Planck Satellite data
- Naty1
- · Replies 20 ·
Graduate Composition of the Universe can be Derived from PI?
- zeroace
- · Replies 21 ·
Undergrad Is intelligent life inevitable given the universe's size and chemistry?
- Whateverworks
- · Replies 91 ·
Interesting facts about the Universe
- 42Physics
- · Replies 1 ·
Stargazing New cosmic model parameters from South Pole Telescope
- marcus
- · Replies 35 ·
Undergrad Can anything truly be stationary in our constantly moving universe?
- shinnsohai
- · Replies 3 ·
Graduate A history of the universe using the new Planck numbers
- marcus
- · Replies 1 ·
Graduate How Does a Comet's Path Relate to Relativity and Spacetime?
- enceladus_
- · Replies 9 ·
Undergrad What Are the Fastest Moving Objects in the Universe?
- EskWIRED
- · Replies 11 ·
Graduate Is there a reference frame where I'm absolutely at rest?
- fivetide
- · Replies 5 ·
Graduate How Does Particle Size Influence Emissivity in Circumstellar Dust?
- robotopia
- · Replies 4 ·
Graduate Large Scale anomaly in Planck data
- skydivephil
- · Replies 11 ·
Graduate Is Wikipedia's Explanation of Olber's Paradox Misleading?
- HowardTheDuck
- · Replies 14 ·
High School From where did our earth get its initial velocity ?
- Sab95
- · Replies 7 ·
Undergrad Best tables for data of objects in our solar system?
- Elecomputer
- · Replies 3 ·
Graduate The Higgs mechanism and the Beginning of the Universe
- Paulibus
- · Replies 22 ·
Graduate Planck mission constraints on inflation and dark energy models
- Chronos
- · Replies 5 ·
Graduate Inflation of singularity at moment of evaporation?
- jks067
- · Replies 9 ·
Planck satellite results live webcast, March 21
- skydivephil
- · Replies 10 ·
Undergrad Why does a third black hole get pushed away when three collide?
- huhjinsoo
- · Replies 7 ·
Undergrad Inner and outer limits of the habitable zone around the Sun
- willstaruss22
- · Replies 26 ·
Undergrad Evolution of a star from a nebula
- Sab95
- · Replies 1 ·
Graduate Is the universe large and finite, or infinite?
- Luciano Kurban
- · Replies 2 ·
Graduate How can the universe be infinite, if it has a finite age?
- Thomas1989
- · Replies 1 ·
Graduate On the formation of larger bodies in space after dust attraction.
- Novawatcher
- · Replies 2 ·
Graduate What is a Vacuum in General Relativity?
- Brook
- · Replies 8 ·
Graduate Understanding Magnetars and Neutron Stars
- serp777
- · Replies 11 ·
Graduate Neutron Stars: Quantum or Classical Objects?
- Raghnar
- · Replies 2 ·
Graduate Questions about nuclear physics inside a star
- aeonflux
- · Replies 13 ·
Undergrad Gravitation as answer to whether the Universe is infinite?
- ojbway
- · Replies 3 ·
Undergrad Interpreting Gravitational Lensing Images?
- solarblast
- · Replies 2 ·
Undergrad Time Space Matter Characteristics
- grendizer1
- · Replies 3 ·
Graduate What would happen if a black hole sucked in a cloud of hydrogen gas?
- Crazymechanic
- · Replies 15 ·
Undergrad Can Planetary Gravity Flatten an Egg-Shaped Planet?
- jaydnul
- · Replies 9 ·
Graduate Is Dark Matter Absorbing Photons and Emitting Undetectable Radiation?
- rp1220
- · Replies 3 ·
Graduate Differences between polarisations and temperature anisotropies in the
- pleasehelpmeno
- · Replies 1 ·
Graduate History of speed of the expansion of the universe?
- SpaceBear
- · Replies 4 ·
High School Looking for some good websites for Physics and Cosmology
- 42Physics
- · Replies 3 ·
Graduate What speed do quasars eject matter out the galaxy?
- Teslanumber1
- · Replies 8 ·
Photo of Jupiter's moons with cellphone
- Gliese123
- · Replies 39 ·