Astronomy, Astrophysics, Cosmology Forum

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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.
Undergrad Night skies in a contracting universe, would they look blue?
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High School The big bang singularity and black hole singularity
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Stargazing What is the true extent of the semi-major axis for companion stars?
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Undergrad Escape Velocity: Unraveling the Mysteries of Kinetic & Potential Energy
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Undergrad Why was the early universe opaque?
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Stargazing Telescope or Binoculars for First Astronomy Device?
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High School Is the Galileon theory an alternative to GR
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Stargazing Don't Crush that Dwarf Planet, Hand me the Pliers
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High School Where is the CG between the Earth and the Moon
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Undergrad Are Quantum Fluctuations Valid Causes for Universe Creation?
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Stargazing Stars in sky given arbitrarily sized/oriented window
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Graduate Is there a polarisation of the microwave background
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Stargazing Is it worth getting a telescope?
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Undergrad Why do nebulae tend to collapse into discs?
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High School In Cosmic First, Scientists Spy a Star's Snow Line
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Undergrad Center of the Universe: What Again
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High School Are universe and big bang considered to be the same thing?
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Stargazing Artificial Stars for testing telescopes: the final answer?
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Stargazing Is cheap CCD worth the cost for astrophotography?
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Undergrad Redshifts of galaxies and the expansion of the universe
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High School The speed of light and Hubble Flow
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High School Gravitational Waves & Dark Matter: Is There a Connection?
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Undergrad Physics & Objects Beyond Space & Time: Big Bang Singularity & Black Holes
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Undergrad Solar physics: coronal holes & sunspot cycles
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Undergrad Causally separated regions in CMB?
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Graduate Could Earth Support Two Moons in Different Orbits?
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High School Outer Solar System Origins Survey, Dwarf Planets and TNOs
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Undergrad Stopping or re-routing comet 67p
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Undergrad How Can We Measure Redshift Using the Spectrum of a Star?
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Undergrad How can we measure a galaxy's velocity via a star?
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Undergrad Determine the temperature of a star via its spectrum
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High School Pale Red Dot Mission: Launching Probes to Alpha Centauri in 2030s
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High School Influx vs. radius equation, mistake in the dimensions?
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Undergrad Why do we calculate the density of states using k-space?
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High School If there is explosion with absence of oxygen?
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Undergrad Neutron Star Stability: Speed of Sound vs Light
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High School Acoustic Waves & Their Impact on Inflation: What You Need to Know
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Undergrad Seeing the Martian moons with a pair of $60 binoculars
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Undergrad How ancient found that sun is too far from earth?
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Undergrad Why is an improbable early universe unacceptable?
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High School Calculating Time to Reach 100,000 Trillion Meters in Hubble Flow | PF Forum
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Undergrad Unraveling the Mystery: The Composition of Quasars
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Undergrad Sun and hydrostatic equilibrium
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Graduate Must Planetary Systems Have Retrograde Orbit Planets?
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Undergrad Disequilibrium of the solar system
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Undergrad Why does temperature always rise in stars?
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Undergrad The cold interior of the Sun seen in a sun spot
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Graduate When Will Preliminary Gaia Data Be Released?
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High School Could We Colonize Mercury Using Sunshades and Heat Shields?
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High School How did direct collapsing black holes form so early in the universe?
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Undergrad Universe is a sphere that is centered on any observer? How?
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High School How exactly do SMBHs in the center of galaxies form
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Graduate How to convert between different mass measurements for CDM H
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Graduate Nature of radiation emanating from a body v/s frequency
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High School Orbital parameters of stars orbiting Sagittarius A*
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Undergrad Are Black Holes Truly 3D Phenomena?
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Undergrad How to define the rotation of a planet in retograde orbit?
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High School How far from the core is the photosphere/chromosphere?
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High School ASTRO-H Failure Puts Promising Mission in Jeopardy | JAXA Update
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Undergrad Does the Universe have a centre, yes or no?
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Undergrad How well are orbital inclination oscillations known?
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Undergrad What Insights on Time in Physics and Cosmology Emerged from the Pi Conference?
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Undergrad Infinite Universe from Dimensionless SIngularity
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High School Is the Age of the Universe a Coincidence?
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High School Aphelion: See Sun's Size Change Over Year on YouTube
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Undergrad Could Dark Energy Be an Illusion of Spacetime Geometry?
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High School Who was the observer for the first 10 billion years?
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Stargazing New Radio Telescope is World's Largest
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High School How can I do Astronomy from home?
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High School From a 4D perspective would 3D infinity exist?
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High School Constructing Space Without Points: Agree/Disagree?
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High School How does having long exposure help with distance in photos?
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High School What is a quantum fluctuation....
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High School Understanding the Lagrange Points: What's Going Wrong with L2 and L3?
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Undergrad Seeking "simple" orbital path planning for game development
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Undergrad Can someone please explain to me Leavitt's law?
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High School How are neutrinos distributed in the universe?
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High School Are massive gravitons what ripple when galaxies collide?
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High School A new quasi-satellite was discovered in April: 2016 HO3
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Undergrad Age of the Universe as Measured by a Non-Co-Moving Observer
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High School How can dark matter exist in a vacuum?
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High School Understanding the Weakness of Gravity and its Role in the Universe
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High School How is the Age of the Universe Determined?
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High School Why is the age of the Universe finite?
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Undergrad Radius and Mass of an Unknown Planet
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Undergrad What Size Space Bombs Would Detonate in Midair Based on Their Composition?
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Graduate Does Dark Energy follow the same rule as energy?
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Undergrad Are Galaxies Moving Faster Than Light Due to Space Expansion?
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Undergrad Light and our atmosphere (some quantum physics)
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Undergrad What does "expansion of the universe" mean?
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Undergrad Time translation symmetry and the Big Bang
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Graduate Transition from opaque universe to release of CMB
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High School What exactly is L, Lz and E in orbital mechanics?
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Undergrad Are Exotic Leptons Crucial for Life's Existence?
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Stargazing Deep Space Imaging and stacking images for less noise
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High School What Causes the 2.7 Kelvin Temperature in the Vacuum of Space?
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High School Is dark matter a sea of massive photons?
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High School Is the Variable Speed of Light Theory a Viable Alternative to Inflation?
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Undergrad Detecting Entanglement in the Inflationary Potential: Is it Possible?
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High School The universe is crowded with black holes
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