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 Is Jupiter too big to orbit the Sun?
- Oganesson
- · Replies 5 ·
Undergrad How can quasars change brightness in days if they're light-years across?
- Phys12
- · Replies 8 ·
Undergrad How do I convert the number of efolds to conformal time during inflation?
- Xepto
- · Replies 3 ·
Graduate Textbooks on orbital mechanics and computational tools for satellite navigation
- Matter_Matters
- · Replies 7 ·
Undergrad How can the integral be rewritten using a change of variables?
- Lapidus
- · Replies 1 ·
High School Hubble flow and velocity addition
- Stephanus
- · Replies 2 ·
Undergrad Rotation curves of galaxies as a function of isolation.
- WCOLtd
- · Replies 12 ·
Undergrad First atmospheric spectroscopy of Earth-sized exoplanets
- mfb
- · Replies 3 ·
Graduate What is the genesis of quantum foam, Planck constant, and string theory?
- lucivaldo
- · Replies 2 ·
Undergrad Difference between hubble sphere,particle horizon and event
- Figaro
- · Replies 11 ·
Undergrad What is the significance of the cosmological jerk in the expanding universe?
- Ontophobe
- · Replies 5 ·
Undergrad Can we avoid infinity in cosmological models of the universe's beginning?
- windy miller
- · Replies 13 ·
Stargazing Building a radio telescope that produces images
- jamalkoiyess
- · Replies 12 ·
Undergrad Where do high energy background photons go?
- fxdung
- · Replies 10 ·
Undergrad 3D map of the universe validates Einstein's theories
- Tom.G
- · Replies 1 ·
Undergrad Can Unification of Forces Coexist with an Eternally Inflating Universe?
- Ranku
- · Replies 9 ·
High School Where Can I Find Math for Black Hole Firewalls?
- MrPhysicsGuy
- · Replies 3 ·
High School Is the Speed of Light Dependent on the Size of the Universe?
- wolram
- · Replies 42 ·
Undergrad Who really found out the Universe's acceleration?
- Phys12
- · Replies 7 ·
Undergrad Relations resolves singularity -- new paper on arxiv
- windy miller
- · Replies 15 ·
Undergrad How Similar Are the Images from BOSS and CMB Planck Spacecraft?
- exponent137
- · Replies 2 ·
Undergrad Which light do we use to measure flux?
- Phys12
- · Replies 1 ·
Undergrad Is Dark Energy an Established Force in the Universe?
- iDimension
- · Replies 4 ·
Undergrad Scale factor/redshift formula wrong at the end?
- Phys12
- · Replies 2 ·
High School Could a research base on Mercury be the key to unlocking solar mysteries?
- GTOM
- · Replies 19 ·
High School Is the Universe Finite or Infinite?
- newrd
- · Replies 47 ·
Undergrad Gravitational waves affected by gravity?
- DuckAmuck
- · Replies 26 ·
Undergrad Energy Released in Stellar Nucleosynthesis
- Amrator
- · Replies 2 ·
Undergrad State of the Universe if we increase/decrease the binding energy of deuterium
- Phys12
- · Replies 1 ·
Stargazing Which Telescope Should I Buy for City and Country Use?
- Cr74
- · Replies 12 ·
Undergrad Night skies in a contracting universe, would they look blue?
- Gerinski
- · Replies 8 ·
High School The big bang singularity and black hole singularity
- wolram
- · Replies 5 ·
Stargazing What is the true extent of the semi-major axis for companion stars?
- ckirmser
- · Replies 11 ·
Undergrad Why does kinetic energy become zero at infinity during escape?
- Rachana MN
- · Replies 1 ·
Undergrad Why was the early universe opaque?
- Phys12
- · Replies 7 ·
Stargazing Telescope or Binoculars for First Astronomy Device?
- russ_watters
- · Replies 14 ·
High School Is the Galileon theory an alternative to GR
- wolram
- · Replies 1 ·
Stargazing Don't Crush that Dwarf Planet, Hand me the Pliers
- diogenesNY
- · Replies 1 ·
High School Where is the CG between the Earth and the Moon
- thetexan
- · Replies 8 ·
Undergrad Are Quantum Fluctuations Valid Causes for Universe Creation?
- momo666
- · Replies 3 ·
Stargazing Stars in sky given arbitrarily sized/oriented window
- Phil A
- · Replies 5 ·
Graduate Is there a polarisation of the microwave background
- trevor white
- · Replies 2 ·
Stargazing Is it worth getting a telescope?
- Tyler Wayne
- · Replies 23 ·
Undergrad Why do nebulae tend to collapse into discs?
- Frank Castle
- · Replies 8 ·
High School In Cosmic First, Scientists Spy a Star's Snow Line
- Spinnor
- · Replies 1 ·
Undergrad How does the universe have a size if it has no center?
- trainman2001
- · Replies 6 ·
High School Are universe and big bang considered to be the same thing?
- Pjpic
- · Replies 16 ·
Stargazing Artificial star vs red LED collimator for Dobsonian collimation
- sophiecentaur
- · Replies 17 ·
Stargazing Is cheap CCD worth the cost for astrophotography?
- Clever Penguin
- · Replies 12 ·
Undergrad Redshifts of galaxies and the expansion of the universe
- kent davidge
- · Replies 6 ·
High School The speed of light and Hubble Flow
- Stephanus
- · Replies 7 ·
High School Are gravitational waves connected to dark matter?
- steveJOBS
- · Replies 4 ·
Undergrad Can objects exist outside space and time, like black holes or the Big Bang singularity?
- momo666
- · Replies 7 ·
Undergrad Relationship between coronal holes and the sunspot cycle
- windy miller
- · Replies 3 ·
Undergrad Causally separated regions in CMB?
- DuckAmuck
- · Replies 2 ·
Graduate Could Earth Support Two Moons in Different Orbits?
- petrushkagoogol
- · Replies 8 ·
High School Outer Solar System Origins Survey, Dwarf Planets and TNOs
- Astronuc
- · Replies 2 ·
Undergrad Stopping or re-routing comet 67p
- clint martin
- · Replies 10 ·
Undergrad How Can We Measure Redshift Using the Spectrum of a Star?
- Phys12
- · Replies 3 ·
Undergrad How can we measure a galaxy's velocity via a star?
- Phys12
- · Replies 2 ·
Undergrad Determine the temperature of a star via its spectrum
- Phys12
- · Replies 2 ·
High School Pale Red Dot Mission: Launching Probes to Alpha Centauri in 2030s
- Clever Penguin
- · Replies 23 ·
High School Influx vs. radius equation, mistake in the dimensions?
- Phys12
- · Replies 2 ·
Undergrad Why do we calculate the density of states using k-space?
- 11thHeaven
- · Replies 1 ·
High School If there is explosion with absence of oxygen?
- Bong Bong
- · Replies 8 ·
Undergrad Neutron Star Stability: Speed of Sound vs Light
- GeorgeDishman
- · Replies 3 ·
High School Acoustic waves after inflation and horizon re-entry timing
- Discman
- · Replies 4 ·
Undergrad Seeing the Martian moons with a pair of $60 binoculars
- Alltimegreat1
- · Replies 4 ·
Undergrad How ancient found that sun is too far from earth?
- parshyaa
- · Replies 1 ·
Undergrad Why is an improbable early universe unacceptable?
- student34
- · Replies 30 ·
High School Time to reach distances in Hubble flow using integral calculus
- Stephanus
- · Replies 5 ·
Undergrad What are quasars made of?
- oliviaawheeler
- · Replies 8 ·
Undergrad Sun and hydrostatic equilibrium
- Andreas C
- · Replies 2 ·
Graduate Must Planetary Systems Have Retrograde Orbit Planets?
- petrushkagoogol
- · Replies 8 ·
Undergrad Disequilibrium of the solar system
- petrushkagoogol
- · Replies 3 ·
Undergrad Why does temperature always rise in stars?
- astrolollo
- · Replies 3 ·
Undergrad The cold interior of the Sun seen in a sun spot
- oz93666
- · Replies 4 ·
Graduate When Will Preliminary Gaia Data Be Released?
- bitznbitez
- · Replies 3 ·
High School Could We Colonize Mercury Using Sunshades and Heat Shields?
- Alltimegreat1
- · Replies 37 ·
High School How did direct collapsing black holes form so early in the universe?
- wolram
- · Replies 1 ·
Undergrad Universe is a sphere that is centered on any observer? How?
- Lohan
- · Replies 17 ·
High School How exactly do SMBHs in the center of galaxies form
- CrackerMcGinger
- · Replies 36 ·
Graduate How to convert between different mass measurements for CDM H
- floyd0117
- · Replies 5 ·
Graduate Nature of radiation emanating from a body v/s frequency
- petrushkagoogol
- · Replies 2 ·
High School Orbital parameters of stars orbiting Sagittarius A*
- jimbo007
- · Replies 44 ·
Undergrad Are Black Holes Truly 3D Phenomena?
- Bujon
- · Replies 5 ·
Undergrad How to define the rotation of a planet in retograde orbit?
- Alltimegreat1
- · Replies 13 ·
High School How far from the core is the photosphere/chromosphere?
- Andreas C
- · Replies 2 ·
High School JAXA's ASTRO-H satellite loses contact after launch
- 1oldman2
- · Replies 13 ·
Undergrad Does the Universe have a centre, yes or no?
- KoenGerits
- · Replies 4 ·
Undergrad How well are orbital inclination oscillations known?
- Hennie Mouton
- · Replies 1 ·
Undergrad Pi conference videos on time in physics and cosmology
- windy miller
- · Replies 5 ·
Undergrad Infinite Universe from Dimensionless SIngularity
- Lucifuge Rofocale
- · Replies 17 ·
High School Is the Age of the Universe a Coincidence?
- wolram
- · Replies 9 ·
High School Aphelion: See Sun's Size Change Over Year on YouTube
- tony873004
- · Replies 1 ·
Undergrad Could Dark Energy Be an Illusion of Spacetime Geometry?
- allen1966
- · Replies 4 ·
High School Who was the observer for the first 10 billion years?
- newrd
- · Replies 6 ·
Stargazing New Radio Telescope is World's Largest
- Tom.G
- · Replies 3 ·
High School How can I do Astronomy from home?
- Phys12
- · Replies 4 ·
High School From a 4D perspective would 3D infinity exist?
- thefredman
- · Replies 2 ·