Astronomy, Astrophysics, Cosmology Forum

Post thread
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 What Happens if a Supernova's Gamma Rays Reach Earth?
  • · Replies 5 ·
Replies
5
Views
3K
Undergrad How Does Time Dilation Affect Our Understanding of the Universe's Age?
  • · Replies 3 ·
Replies
3
Views
3K
Graduate Ballon expansion vs raisin bread expansion
  • · Replies 26 ·
Replies
26
Views
9K
Graduate The boundaries between individual universes
  • · Replies 2 ·
Replies
2
Views
2K
Graduate Computing the halo mass function and the SFH
  • · Replies 2 ·
Replies
2
Views
2K
Graduate Anti-matter vs matter at creation.
  • · Replies 15 ·
Replies
15
Views
4K
Graduate Was Halton Arp hard done by? Need some clarification. some pictures
  • · Replies 75 ·
3
Replies
75
Views
17K
Graduate Orbital effect of a sudden change to G
  • · Replies 3 ·
Replies
3
Views
3K
High School Where can I find equatorial coordinates of celestial objects?
  • · Replies 4 ·
Replies
4
Views
5K
High School Position of Sun at noon between the Equator and Tropic of Cancer
  • · Replies 1 ·
Replies
1
Views
3K
Graduate What Are the Best Resources for Researching Dark Energy?
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Can We Go "Outside the Universe"?
  • · Replies 29 ·
Replies
29
Views
6K
Graduate Uniform redshift in inflationary model?
  • · Replies 2 ·
Replies
2
Views
3K
Graduate Questions on Redshift, Hubble’s Law, spacetime expansion and the standard model
  • · Replies 21 ·
Replies
21
Views
5K
High School I was watching Stephen Hawking Into the universe and he was talking
  • · Replies 12 ·
Replies
12
Views
3K
High School If earths rotation stoped, the moon would be released.
  • · Replies 81 ·
3
Replies
81
Views
18K
Graduate Hubble law&galaxies w speeds faster than light
  • · Replies 7 ·
Replies
7
Views
4K
Undergrad Perpetual Motion: Is Cosmos an Endless Machine?
  • · Replies 26 ·
Replies
26
Views
7K
Graduate Time Theories: Outta Universe, Relativity, Multiverse
  • · Replies 14 ·
Replies
14
Views
4K
Graduate If gravitation is mediated via particle doesn't it mean thatthis
  • · Replies 15 ·
Replies
15
Views
6K
Graduate Equation for the energy of Hawking Radiation
  • · Replies 1 ·
Replies
1
Views
3K
Graduate Does the universe have an overall rotation?
  • · Replies 5 ·
Replies
5
Views
5K
High School What happen to gravity in the center of earth
  • · Replies 12 ·
Replies
12
Views
5K
Graduate Why do scientists believe white holes are impossible?
  • · Replies 63 ·
3
Replies
63
Views
19K
Graduate Did the basic laws of physics also evolve after BB?
  • · Replies 2 ·
Replies
2
Views
3K
Graduate Robertson-Walker metric and time expansion
  • · Replies 54 ·
2
Replies
54
Views
11K
Graduate Why Do Planets with the Same Orbital Period Have the Same Average Density?
  • · Replies 3 ·
Replies
3
Views
2K
Graduate Does velocity increase gravitation?
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad How long could it take for the Earth to be in the exact same place as it was?
  • · Replies 7 ·
Replies
7
Views
9K
Graduate Could Dinosaurs Weigh Less Due to Ancient Gravitational Forces?
  • · Replies 9 ·
Replies
9
Views
24K
Graduate Is Our Universe Based on Finite Geometry?
  • · Replies 1 ·
Replies
1
Views
2K
Graduate Magnetism and Ampere-Maxwell's law
  • · Replies 7 ·
Replies
7
Views
5K
What is Dark Matter? | Just Curious
  • · Replies 6 ·
Replies
6
Views
2K
Graduate Is LQC compatible with dark energy?
  • · Replies 1 ·
Replies
1
Views
2K
Graduate Chasing the edge of the universe?
  • · Replies 1 ·
Replies
1
Views
2K
Does peace occur before real space travel ?
  • · Replies 94 ·
4
Replies
94
Views
17K
Stargazing What is the advantage of a binocular telescope (such as the LBT)?
  • · Replies 1 ·
Replies
1
Views
5K
High School How Long Does Earth Rotate Around the Earth-Moon Barycentre?
  • · Replies 3 ·
Replies
3
Views
4K
Undergrad Emission line in spectrum of a sun
  • · Replies 1 ·
Replies
1
Views
3K
Graduate What happens when a ray of light hits the boundary of the universe?
  • · Replies 66 ·
3
Replies
66
Views
18K
Graduate How do collisions affect the evolution of objects in the Oort cloud?
  • · Replies 2 ·
Replies
2
Views
5K
Graduate Matter creation, dark energy, and the possibility of a Big Crunch
  • · Replies 6 ·
Replies
6
Views
4K
High School Help a Physics Amateur - See Attachment!
  • · Replies 10 ·
Replies
10
Views
5K
Graduate Early universe: equilibrium before nucleosynthesis
  • · Replies 9 ·
Replies
9
Views
3K
Graduate The Value of the Cosmological Constant
  • · Replies 13 ·
Replies
13
Views
6K
Graduate Theorists predicted the big bang to expand faster than the speed of light
  • · Replies 12 ·
Replies
12
Views
4K
Graduate How often do small asteroids reach the Earth's solid surface?
  • · Replies 23 ·
Replies
23
Views
7K
Graduate Can a star with a black hole core be stable?
  • · Replies 6 ·
Replies
6
Views
3K
Graduate What is the total mass of the heliosphere approximately? And its
  • · Replies 1 ·
Replies
1
Views
3K
Graduate How Do CMBR Variations Differ Across Planets?
  • · Replies 2 ·
Replies
2
Views
4K
Undergrad Redshift: Speed of Light & Beyond?
  • · Replies 1 ·
Replies
1
Views
3K
Undergrad Why does gravity make things spin?
  • · Replies 40 ·
2
Replies
40
Views
27K
Undergrad How to Calculate Angular Diameter of a Galaxy with a Given Diameter?
  • · Replies 2 ·
Replies
2
Views
3K
Graduate The properties of light over time/distance
  • · Replies 4 ·
Replies
4
Views
3K
Graduate Spacetime, like an isometric weather map?
  • · Replies 2 ·
Replies
2
Views
3K
Graduate Calculating the density of a HII region
  • · Replies 2 ·
Replies
2
Views
4K
Undergrad What Data is Needed to Understand the Formation of Black Hole Jets?
  • · Replies 42 ·
2
Replies
42
Views
12K
Undergrad Big Bang Theory: Is Everything Energy?
  • · Replies 3 ·
Replies
3
Views
3K
Mars Age Two to Four Million Years?
  • · Replies 9 ·
Replies
9
Views
4K
Graduate Will the speed of light change in the Universe's distant future?
  • · Replies 12 ·
Replies
12
Views
4K
Graduate Space expansion vs. time speeding up
  • · Replies 1 ·
Replies
1
Views
4K
Graduate Is the Universe's Expansion Rate Actually Slowing Down?
  • · Replies 3 ·
Replies
3
Views
3K
Graduate Aussie Student Solves Mystery of Missing Mass in Universe
  • · Replies 1 ·
Replies
1
Views
3K
Undergrad Star density, outside our galaxy
  • · Replies 11 ·
Replies
11
Views
6K
Graduate Is Dark Energy Tearing Us Apart Atom by Atom?
  • · Replies 2 ·
Replies
2
Views
3K
Graduate When will we be able to image the Oort cloud?
  • · Replies 1 ·
Replies
1
Views
2K
Graduate Does My Vision of the Big Bang Reflect Mainstream Scientific Theories?
  • · Replies 13 ·
Replies
13
Views
3K
Graduate Is GRB090429b at the Edge of the Observable Universe?
  • · Replies 7 ·
Replies
7
Views
4K
Stargazing Most powerful telescope system of the future?
  • · Replies 31 ·
2
Replies
31
Views
11K
Graduate N-Body simulation: MERCURY vs. Swift
  • · Replies 7 ·
Replies
7
Views
6K
Graduate What are the properties of electron gas in the Sun?
  • · Replies 5 ·
Replies
5
Views
3K
Undergrad Is AMS-02 Truly a Game-Changer in Space Exploration?
  • · Replies 5 ·
Replies
5
Views
3K
Undergrad Cosmology History: Timeline, Discoveries & Current Theories
  • · Replies 6 ·
Replies
6
Views
3K
High School Unraveling the Mystery of the Moon's Non-Spinning Rotation
  • · Replies 61 ·
3
Replies
61
Views
40K
Undergrad Distribution of planets material
  • · Replies 10 ·
Replies
10
Views
4K
Graduate Cold Dark Matter vs Hot Dark Matter
  • · Replies 7 ·
Replies
7
Views
5K
Undergrad Milky Way: Star & H-Atom Distribution
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad What Does It Mean for the Universe to Be Flat?
  • · Replies 22 ·
Replies
22
Views
17K
Undergrad Atmospheric Surface Pressure and Density
  • · Replies 1 ·
Replies
1
Views
3K
Undergrad Asteroid Density & Impact Rate - Earth vs Mars
  • · Replies 4 ·
Replies
4
Views
4K
Undergrad What is the binding energy needed to shatter Earth by asteroid impact?
  • · Replies 8 ·
Replies
8
Views
5K
Undergrad Simulation of formation of a solar system
  • · Replies 1 ·
Replies
1
Views
5K
Graduate Why Does Angular Diameter Distance Decrease After Redshift z=1.5?
  • · Replies 3 ·
Replies
3
Views
6K
Graduate A puzzling thought about the Big Bang & after
  • · Replies 4 ·
Replies
4
Views
3K
Graduate Deriving the Relation for Escape Velocity from a Proto-Star Cloud
  • · Replies 2 ·
Replies
2
Views
3K
Graduate Cosmological Models Predicting Heat Death of the Universe
  • · Replies 8 ·
Replies
8
Views
5K
Undergrad Determining the mass of globular cluster?
  • · Replies 3 ·
Replies
3
Views
7K
Graduate Entropy and the big bang on to the big crunch and back
  • · Replies 1 ·
Replies
1
Views
2K
High School Lifetime of Earth: Planet vs Sun
  • · Replies 3 ·
Replies
3
Views
3K
Graduate How this equality exist between time and distance and the velocity
  • · Replies 6 ·
Replies
6
Views
3K
Undergrad Universe Today: What Does It Look Like?
  • · Replies 2 ·
Replies
2
Views
3K
High School Discovering Binary Universe: Albert Einstein & Beyond
  • · Replies 3 ·
Replies
3
Views
3K
Explore the Interactive Panoramic of Space
  • · Replies 1 ·
Replies
1
Views
2K
Graduate What Insights Can Gamma Photon Distribution in the Galaxy Provide?
  • · Replies 1 ·
Replies
1
Views
2K
Graduate Center of Mass of Universe: Is it Nowhere, Everywhere?
  • · Replies 14 ·
Replies
14
Views
5K
Graduate Black holes and higher dimensional universe
  • · Replies 4 ·
Replies
4
Views
4K
High School Particle Motion 2: Floating, Flying & Moving Freely in Space
  • · Replies 7 ·
Replies
7
Views
3K
High School French claim first habitable planet found
  • · Replies 4 ·
Replies
4
Views
4K
Graduate H-alpha line in galaxies/ hubble redshift
  • · Replies 1 ·
Replies
1
Views
3K
Undergrad How Does Gravity Cause Acceleration Towards a Massive Object in Space?
  • · Replies 4 ·
Replies
4
Views
2K