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 GW170817: Limits on D>4 Spacetime Dimensions
- fresh_42
- · Replies 2 ·
High School High School Astro Club: Teaching Astronomy in a City
- nmsurobert
- · Replies 2 ·
Undergrad Testing inflation against bouncing and ekpyrotic models
- windy miller
- · Replies 6 ·
High School Density of the early Universe contributing to the red-shift?
- D.S.Beyer
- · Replies 26 ·
Undergrad Variations in the speed of sound in a star
- fab13
- · Replies 5 ·
Undergrad What is it that forces an object down curved space time?
- vincent
- · Replies 11 ·
Undergrad Zero Active Mass in FRW cosmologies
- jcap
- · Replies 3 ·
High School Is right ascension only measured once a year?
- DonutLord
- · Replies 6 ·
Undergrad What is the Janus Universe and its implications for the arrow of time?
- windy miller
- · Replies 4 ·
High School What is Olbers' Paradox and how does it relate to the universe's structure?
- alejandromeira
- · Replies 2 ·
Undergrad Is there some prediction of the speed of rings?
- Prometeus
- · Replies 6 ·
Undergrad How to get state vector in 4-observation method of Gauss
- Jenab2
- · Replies 2 ·
Undergrad Is the expansion actually accelerating? Or does it just appear so?
- Inani Schroedinger
- · Replies 4 ·
Undergrad Why Do Astrophysicists Use νLν in Accretion Disk Emission Studies?
- Astroiaco
- · Replies 7 ·
High School Is the Universe a 3D Cut of a 4D object?
- Reapphil
- · Replies 10 ·
Undergrad Positions of distant supernova explosions false?
- kiki_danc
- · Replies 31 ·
Undergrad Neutron Stars mass and radii observation data
- Leonardo Machado
- · Replies 1 ·
Undergrad Is the universe actually just mass and length?
- babaliaris
- · Replies 7 ·
Undergrad 55x times harder to get to the Sun?
- fizzy
- · Replies 18 ·
High School The accelerating expansion of the universe
- kolleamm
- · Replies 3 ·
Undergrad How was the value of the permittivity of free space determined?
- Steven_Scott
- · Replies 7 ·
Stargazing Space Station Live Video of the Earth
- Tom.G
- · Replies 6 ·
Graduate 3-star triangular orbit possible?
- CookieSalesman
- · Replies 18 ·
Undergrad Why are planetary orbits not aligned with the Sun's rotation?
- rootone
- · Replies 1 ·
High School Questions About the Growth of the Universe
- J251H
- · Replies 4 ·
Undergrad Solving Kepler's problem given initial velocity and impact parameter
- L0r3n20
- · Replies 9 ·
Undergrad What is the purpose of Cosmology and where can I find information about it?
- TNUTUNU
- · Replies 3 ·
Undergrad Why don't red dwarf stars emit white light like the Sun?
- James2018
- · Replies 9 ·
Undergrad Why does the 3:5 orbital resonance between Jupiter and Saturn occur?
- rootone
- · Replies 11 ·
High School An observer looking at Earth's past history
- happyhacker
- · Replies 3 ·
Graduate What volume of interstellar space is needed to form a star?
- anyman
- · Replies 7 ·
Undergrad Is the sun a perfect black body?
- YoungPhysicist
- · Replies 9 ·
High School Brown Dwarf Mass Gain: Does Radius Increase?
- tovisonnenberg
- · Replies 5 ·
High School Thank you for understanding. Have a great day!
- shimun
- · Replies 55 ·
Undergrad Is Dark Matter Really a Cold, Collisionless Fluid?
- Robin04
- · Replies 80 ·
High School Are Deep Space Objects Still There?
- Edeff
- · Replies 6 ·
Undergrad BAO : Relation between redshift, Hubble constant and radial
- fab13
- · Replies 1 ·
Undergrad Radial dependence of the Sun's magnetic field
- prodi
- · Replies 4 ·
Undergrad Would going to the Moon delay going to Mars?
- Al_
- · Replies 28 ·
High School Are all wavelengths of light possible?
- AGuglielmone
- · Replies 8 ·
Undergrad Will Space Expansion Lead to the Formation of Black Holes and Neutron Stars?
- Meuchedet
- · Replies 1 ·
Insights Either the Sun Is Getting Smaller or Gravity Is Getting Weaker
- klotza
- · Replies 30 ·
Undergrad What problems would 'black holes' not being formed solve?
- DarkStar42
- · Replies 90 ·
Graduate Deriving the WIMP dark matter relic abundance equation
- Thiwanka Jayasiri
- · Replies 24 ·
Undergrad Why discuss events before the Big Bang if time began with it
- rumborak
- · Replies 8 ·
Undergrad Why are there so many different kinds of stars?
- sjp9220
- · Replies 23 ·
High School Why is space black in visible light and what do other wavelengths reveal?
- nivamani Rajbongshi
- · Replies 5 ·
High School What can be used to propel something in space without fuel?
- Andrew broome
- · Replies 17 ·
Graduate Penrose CCC: BICEP2 B-modes from void magnetic fields correlated to Hawking Points
- Auto-Didact
- · Replies 6 ·
High School How Long After the Big Bang Did Life First Emerge?
- dahoa
- · Replies 8 ·
Undergrad Is There a Model to Define Earth's Position in the Milky Way?
- Cosmic Gazelle
- · Replies 3 ·
Graduate Does the Hubble diagram show deceleration rather than acceleration?
- meatym
- · Replies 2 ·
Undergrad Is the time since the Big Bang the same everywhere in the universe?
- clinden
- · Replies 8 ·
Graduate Phase Space and Its Use in Monte Carlo Simulations of Radiation Beams
- Gruxg
- · Replies 1 ·
Stargazing Phase of radio waves received by a radio telescope dish
- jordankonisky
- · Replies 56 ·
High School Why don't high mass stars expand and cool?
- tovisonnenberg
- · Replies 8 ·
Undergrad Trying to reproduce curves with angle of CMB anisotropies
- fab13
- · Replies 1 ·
Undergrad Hawking points in the CMB and conformal cyclic cosmology
- member 342489
- · Replies 5 ·
High School Why will Betelgeuse go supernova?
- tovisonnenberg
- · Replies 9 ·
High School Hubble constant discrepancy between Planck and Hubble measurements
- MikeinSpain
- · Replies 1 ·
High School Is Our Universe a Causal Patch Stretched by Inflation?
- Cerenkov
- · Replies 11 ·
Undergrad Hawking Radiation and the Negative Energy Particle
- Islam Hassan
- · Replies 30 ·
High School Why does a Martian lake appear blue if Mars has a red sky?
- Delta2
- · Replies 7 ·
Undergrad Would Newton's shell theorem prevent binary planet systems?
- DarkStar42
- · Replies 11 ·
High School Planet Nine race, how is it going?
- nikkkom
- · Replies 10 ·
Graduate Multiverse theory with impossible universes?
- Suekdccia
- · Replies 1 ·
High School Is Earths' potential of 0 volts valid throught the Universe?
- Bill Hendry
- · Replies 7 ·
Graduate CMBR anisotropy and cosmic abundances
- Adrian59
- · Replies 20 ·
High School Eta Carinae Is Farther Than You Thought: 8,500 Light-Years
- CygnusX-1
- · Replies 1 ·
Undergrad A discussion on "officially called a planet"
- fizzy
- · Replies 3 ·
Undergrad Troubles understanding slow-roll conditions in Inflation
- "Don't panic!"
- · Replies 9 ·
Undergrad Dark matter "halo" is a "flattened disk" ?
- phinds
- · Replies 14 ·
Graduate Why Does the Core of Certain Chromospheric Lines Appear in Emission in Sunspots?
- spossatamente
- · Replies 2 ·
High School Our universe's entropy/size vs Bekenstein's theory
- Bob Walance
- · Replies 8 ·
High School Is There a Model That Includes Infinite Space and Finite Matter in Our Universe?
- Mukund
- · Replies 14 ·
Undergrad Does the solar system barycenter ever leave the sun during planetary alignment?
- jim77
- · Replies 13 ·
High School How Do You Determine the Sun's Coordinates?
- Kuzma
- · Replies 3 ·
High School A Question Concerning Lunar Eclipses and Aristarchus's Work
- Mikaelochi
- · Replies 3 ·
High School Was the Big Bang simply "Distant Traffic"?
- ct2193
- · Replies 5 ·
Stargazing The Moon through my El Crapo Telescope
- DennisN
- · Replies 18 ·
Undergrad Least cost to get a self-sustaining space infrastructure
- Al_
- · Replies 7 ·
High School Is our 3D universe a shadow of a 4D Universe?
- Zdravko
- · Replies 9 ·
High School Neutron Star Collisions: Creation of Heavy Elements and Their Fate
- tovisonnenberg
- · Replies 3 ·
Undergrad Could entropy remain the same overall?
- DarkStar42
- · Replies 1 ·
Undergrad Do orbital dynamics scale linearly?
- Russell Patterson
- · Replies 23 ·
Undergrad Why does the expanding universe redshift light?
- tovisonnenberg
- · Replies 7 ·
Undergrad How ionization theory and spectral lines reveal the Sun's hydrogen abundance
- Andrew Church
- · Replies 10 ·
Undergrad Can Relativity Be Confirmed Again with a Star and a Black Hole?
- Tom.G
- · Replies 13 ·
High School A Singularity in Semi-Classical physics too?
- Cerenkov
- · Replies 17 ·
Undergrad Neptune images from VLT better than Hubble
- Tom.G
- · Replies 3 ·
High School How do we know that the universe is still expanding
- Deepblu
- · Replies 7 ·
High School Saturn's Rings Appearance from Saturn?
- gmax137
- · Replies 6 ·
High School Attention: We have an important announcement from our Sun
- jedishrfu
- · Replies 4 ·
High School General relativity and elliptical planetary orbits
- Sai Siddhartha k
- · Replies 5 ·
Undergrad Liquid water reservoir reported under Mars polar cap
- Fewmet
- · Replies 4 ·
Undergrad Which Main Sequence Stars Experience Hot Corona Phenomena Beyond G2?
- spossatamente
- · Replies 1 ·
Undergrad Thoughts on Breakthrough Starshot?
- greswd
- · Replies 22 ·
High School Discussing Sterile Neutrino Candidacy as Dark Matter
- Simon Peach
- · Replies 56 ·
Graduate Do any coordinate systems include self magnification?
- DarkStar42
- · Replies 3 ·
Graduate What is primordial non gaussianity?
- Avi Nandi
- · Replies 4 ·