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 Universe Expansion: Is a Big Crunch Imminent?
- jjgillis1
- · Replies 2 ·
Viewing Discovery and the ISS from Canada and northern US
- turbo
- · Replies 3 ·
Undergrad Gravitational Force: Why is Normal to Path of Satellites, Planets?
- atlantic
- · Replies 2 ·
Graduate CMB Power spectrum/CMB anisotropies -> Geometry of Universe
- DanAbnormal
- · Replies 5 ·
Graduate Maximum value of Hubble parameter (near start of expansion)
- marcus
- · Replies 16 ·
Graduate Does motion cease inside black holes and is time dilation just perception?
- ladykrimson
- · Replies 16 ·
Graduate How do you explain the CMB anisotropy diagram?
- Simfish
- · Replies 1 ·
Graduate Long-range Coulomb interactions in space
- Simfish
- · Replies 3 ·
Graduate How is the observed redshift caused by a recessional velocity?
- mysearch
- · Replies 9 ·
Graduate Book about Measurements in Astronomy and Cosmology
- go quantum!
- · Replies 1 ·
Undergrad Earth's position relative to the Sun.
- Khan Wolf
- · Replies 4 ·
Graduate Substellar temperatures comparable to that of the Earth
- Demon117
- · Replies 1 ·
Graduate Source of energy for white dwarf and neutron star
- starfish99
- · Replies 9 ·
Graduate Hawking radiation from a black hole?
- mAMBOkING
- · Replies 2 ·
Undergrad What Are the Individual Libration Percentages of the Moon?
- Timoothy
- · Replies 3 ·
Graduate Has Dark matter really been proven?
- DontPanic
- · Replies 20 ·
Undergrad Why are solar systems or galaxies flat?
- skeleton
- · Replies 9 ·
Where Do Black Holes Go After They Form?
- tock~tick
- · Replies 22 ·
High School Do all stars rotate, and where does their rotation come from?
- shirin
- · Replies 9 ·
Graduate Can Naked Singularities Exist Through Scalar Field and Gravitational Collapse?
- Huma waseem
- · Replies 5 ·
Graduate Expansion of Universe, do we know the equation?
- magnetoman
- · Replies 3 ·
Graduate What Was the Ratio of Quarks to Antiquarks in the Early Universe?
- bobsmith76
- · Replies 2 ·
Graduate Is the Matter in a Black Hole's Accretion Disc Entering the BH or Circling It?
- abhiroop_k
- · Replies 7 ·
Graduate Do Magnetic Fields Around Black Holes Overpower Gravitational Pull?
- abhiroop_k
- · Replies 7 ·
Graduate Heliocentric and baryocentric corrections.
- theneedtoknow
- · Replies 1 ·
Graduate Calculating travel times on cosmological scales
- mistergrinch
- · Replies 11 ·
Graduate The Frost Line of the Solar System
- TheMan112
- · Replies 10 ·
Undergrad Calculating star's radius and temperature.
- ted1986
- · Replies 11 ·
Graduate Does superfluidity in neutron stars relate to cooling?
- bcrowell
- · Replies 3 ·
Undergrad Why does an object skip off the atmosphere at a shallow angle?
- Shraa
- · Replies 4 ·
Undergrad Red shift and narrowband filters
- Kawakaze
- · Replies 3 ·
What are these lines? (Picture included)
- nhmllr
- · Replies 5 ·
Undergrad What Is Dark Matter and How Do We Know It Exists?
- LSulayman
- · Replies 9 ·
High School How Can Light Be Influenced by Gravity?
- spg89
- · Replies 7 ·
Graduate How does matter escape a white hole's event horizon?
- Pittman
- · Replies 10 ·
Graduate Difference between 'Optical Spectral Type' and 'IR Spectral Type'?
- omoplata
- · Replies 1 ·
Undergrad Navigation through the Asteroid belt
- Bullo1
- · Replies 4 ·
Graduate Radiation condensing into matter?
- εllipse
- · Replies 9 ·
Graduate Initial value for hubble parameter
- apeiron
- · Replies 15 ·
Graduate Could stronger gravity replace dark matter?
- skeleton
- · Replies 12 ·
Graduate Mini-Black Holes and Stars Winking Out
- RJ Emery
- · Replies 9 ·
Graduate How Does Dark Matter Influence the Spin of Galaxies Compared to Solar Systems?
- nhmllr
- · Replies 5 ·
High School Why is Earth's orbit elliptical and not circular?
- Bassalisk
- · Replies 6 ·
High School What is the time of perihelion for different planets?
- Bjarne
- · Replies 1 ·
Undergrad Do Universes Expand Because There's Nothing to Stop Them?
- sherlock ohms
- · Replies 1 ·
Undergrad Is the Red Shift Evidence of an Expanding Universe or an Illusion?
- ape
- · Replies 17 ·
Graduate Calculating Luminosity Distances: Converting Angular Distances to Parsecs
- Radiohannah
- · Replies 2 ·
Graduate How Can We Analyze the Singularity at the Big Bang?
- PhysDrew
- · Replies 6 ·
Stargazing When was the first telescope used to view the stars?
- DaveC426913
- · Replies 4 ·
Graduate Celestial Mass Accretion Spectrum
- Oriako
- · Replies 1 ·
Graduate MOND paper says Bullet Cluster poses problems for Lambda-CDM
- hadsed
- · Replies 2 ·
Undergrad Why did Hubble interpret redshift as expanding space rather than galaxies moving apart?
- LSulayman
- · Replies 9 ·
Undergrad Is there a perfect vacuum between atoms in space?
- saln1
- · Replies 55 ·
Undergrad What Would Happen if Our Sun Became a Pulsar?
- Algaib
- · Replies 4 ·
Graduate Why Do M-Type Stars Exhibit More Diverse Spectral Lines Than O-Type Stars?
- shirin
- · Replies 2 ·
Undergrad Does atmospheric pressure increase with stronger surface gravity?
- brainfuel
- · Replies 7 ·
Graduate How Can the Universe Be 13.7 Billion Years Old but 46 Billion Light Years Wide?
- Algaib
- · Replies 2 ·
Graduate What's the easiest way to move a star?
- TheDonk
- · Replies 12 ·
Undergrad What Causes the Lines in the Spectrum of a Star?
- shirin
- · Replies 7 ·
Undergrad Physics of Propulsion: Learn About Space Travel Tech
- VyRianS
- · Replies 2 ·
Undergrad How could the Big Bang expand faster than light speed?
- The_Original5
- · Replies 10 ·
Undergrad Line of sight and star density question.
- Illuminati
- · Replies 3 ·
Graduate Sign convention of bolometric correction
- phenolic
- · Replies 3 ·
Graduate Is Gravity Faster Than Light in Black Holes?
- Eric R. Blacker
- · Replies 9 ·
Undergrad Would Earth recover its spin rate if the Moon's tidal braking stopped?
- termina
- · Replies 1 ·
Graduate The matter content in the universe when the last scattering happens
- Accidently
- · Replies 6 ·
Undergrad Einstein's Universe: How Relativity Shaped His Understanding
- LSulayman
- · Replies 6 ·
Undergrad Do type Ia supernovae detonate in a fusion explosion?
- qraal
- · Replies 33 ·
High School Why does the Moon keep rotating on its axis?
- quietrain
- · Replies 25 ·
Undergrad Difference between theoretical astrophysics and theoretical physics
- camipol89
- · Replies 1 ·
High School Why Did They Place the Lunar Laser Reflector on the Moon's Near Side?
- r.vittalkiran
- · Replies 12 ·
Graduate Gravitational component of light and neutrinos in the universe
- BernieM
- · Replies 3 ·
Graduate Is the behavior of dark matter contradictory to the formation of black holes?
- cealicu_ca
- · Replies 5 ·
Undergrad Where is Taurus in Relation to the Sun's Orbit in the Milky Way?
- Bjarne
- · Replies 4 ·
High School What are the shapes of orbits that exist in our solar system
- LukeyD
- · Replies 9 ·
Undergrad What are quasars and blazars, and how do they emit if powered by black holes?
- Xander756
- · Replies 2 ·
Graduate Why is dark matter distributed in a web rather than falling into clumps ?
- Robin
- · Replies 9 ·
Graduate How Does Redshift and Lambda-CDM Model Explain the Universe's Expansion?
- Cajun
- · Replies 3 ·
Graduate How to Create and Contain a Black Hole in Fiction
- hairyllama
- · Replies 16 ·
Artistic or Computer Generated Astronomy Images?
- FtlIsAwesome
- · Replies 4 ·
High School How Do You Calculate Acceleration and Distance of a Free-Falling Object?
- jsm6252
- · Replies 4 ·
Graduate Calculating Acceleration of Stellar Engines: A Comparison to Wikipedia Example
- mistergrinch
- · Replies 5 ·
Graduate Is Every Point in the Universe the Center?
- Endervhar
- · Replies 47 ·
Undergrad Shouldn’t ice on comets burn up quickly?
- ZeuZ
- · Replies 11 ·
Graduate How Can We Observe the Oldest and Most Distant Object in the Universe?
- showup
- · Replies 12 ·
Graduate Evidence of inexistence in black holes?
- Pragz
- · Replies 9 ·
Undergrad Trying to wrap my brain around gravitational assists
- Decimator
- · Replies 7 ·
Undergrad Finding the planet mass from Barnard's star oscillation amplitude
- shirin
- · Replies 3 ·
Graduate Why does inflation predict red tilt in the CMB?
- skydivephil
- · Replies 1 ·
Undergrad What made Einstein think the universe was steady?
- LSulayman
- · Replies 15 ·
Undergrad Who was the first one to say universe is expanding?
- LSulayman
- · Replies 17 ·
Graduate Are Orbits of Close Binary Stars Truly Circular?
- shirin
- · Replies 4 ·
Undergrad Calculating Orbital Velocity Ratios for Planets A and B
- mariners02
- · Replies 2 ·
High School What causes tidal gravitational forces?
- shirin
- · Replies 1 ·
Undergrad Kepler's smallest rocky planet: 1.5 Earth radii, 4.5 Earth masses
- Chronos
- · Replies 1 ·
High School Gravitational Force: What Keeps Two Bodies From Colliding?
- RAHIL008
- · Replies 1 ·
Graduate Do atoms really occupy all energy levels equally when kT exceeds the excitation energy?
- shirin
- · Replies 3 ·
Graduate Particle Astrophysics: What Is It?
- hadsed
- · Replies 3 ·
Stargazing Astronomy binoculars like the Celestron Skymaster 20x80?
- mistergrinch
- · Replies 3 ·
Graduate How is the Energy of a Star's Atoms Calculated and Related to its Temperature?
- shirin
- · Replies 3 ·