Notes

• ​Two points of space are considered the same point when the distance between them is zero.​

• The universe doesn't expand into anything. No additional points of space are added -- whether finite or infinite, the universe is best modeled as a continuum (attempts to model space as discrete all seem to have problems) which means it has an uncountably infinite number of points. The expansion of space simply means that distances between any two given points increase over time.

  • Its like having an infinite Cartesian coordinate plane, then scaling it up by a factor of 2 and asking "what did it expand into?" It didn't expand into anything, it just scaled up by a factor of 2, that's all.

• It hasn't been established that the universe came from the single point. That is still speculative, and there are numerous ideas, but not enough data to choose which (if any) are correct.

  • We know that the universe was originally very very hot and very very dense.

  • We don't know if it came from a point, or from another universe that collapsed, or if it just gets asymptotically smaller forever back in time.

• Imagine the universe as an infinite grid. Now, if we reduce the space between each line to 0, the universe becomes a point. But it still has an infinite number of divisions, it's just that it's infinite * 0.

  • No matter how small an increase you make, adding anything to that zero instantly gives you infinite, so yeah.

  • Also thinking of it as an infinite grid might also help you conceptualize what it means for the universe to "expand". It's not expanding into anything, it's already infinite, it's just that the space between the demarcations are getting bigger.

• Also thinking of it as an infinite grid might also help you conceptualize what it means for the universe to "expand". It's not expanding into anything, it's already infinite, it's just that the space between the demarcations are getting bigger. If the Universe is infinite then is always has and always will be.

Links

• ​Ultimate SpaceX Compilation 2003-2018​

• ​Near the core of the Milky Way​

• ​Amazing Carl Sagan video​

• ​How do we measure the size of the universe?​

• ​How will the universe end? When will that happen?​

• ​What Is a Nebula?​

• ​Celestia - Real-time space simulation that lets you experience our universe in three dimensions.

• ​Insight Mission Comic (2018)​

• ​Aliens under the Ice – Life on Rogue Planets (2018)​

• ​ehtim (eht-imaging) - Imaging, analysis, and simulation software for radio interferometry.

• ​Starlink - SpaceX’s broadband internet system. (HN)

• ​Apollo 11 in Real Time (HN)

• ​KubOS - Open source software stack for satellites.

• ​Exoplanets and Cosmology - Nobel Prize in Physics 2019​

• ​Spin doctors: Astrophysicists find when galaxies rotate, size matters (2019)​

• ​Akassh Systems - Focused on developing and supplying the next generation of extreme bandwidth, hyper-efficient communications gear for space satellites.

• ​Astroquery - Contains a collection of tools to access online Astronomical data.

• ​Space Science with Python (2020)​

• ​ELI5: What is space made out of? What is the blackness in space? (2020)​

• ​Titan - A Frozen Oasis | The Lesser Worlds (2019)​

• ​Why are the objects in the space spinning?​

• ​Everyday Astronaut​

• ​SPACEX - ISS Docking Simulator​

• ​SpaceX software team AMA (2020)​

• ​RussianSpaceWeb - News and history of astronautics in the former USSR.

• ​Receiving images of Earth from satellites with software defined radio (HN)

• ​Awesome Space - List of awesome space-related packages and resources.

• ​The Orbital Index - Curated space news and links. Weekly, brief, and technical.

• ​ISS Photo Explorer (HN)

• ​Every Kind of Thing in Space Mapped (2020)​

• ​My dad launched the quest to find alien intelligence (2020) (HN)

• ​Space Search - Search engine for space objects. (HN)

• ​First Ever Image of a Multi-Planet System Around a Sun-Like Star Captured by ESO (2020) (HN)

• ​Project Apollo Archive (Apollo 11 Hasselblad image)

• ​DIY Satellite Ground Station to Receive NOAA Images (HN)

• ​Fastest star ever seen is moving at 8% the speed of light (HN)

• ​What’s Flying Above Us? (HN)

• ​Tour of the outer Solar System in radio light​

• ​Parallel Supercomputing for Astronomy​

• ​Official SpaceX Photos​

• ​Signs of Life discovered on Venus and atmosphere (2020) (HN)

• ​Some Physicists See Signs of Cosmic Strings from the Big Bang (2020) (HN)

• ​NASA technical note: Lunar sample processing​

• ​100k Stars (HN)

• ​Space Engine - Universe simulator. (HN) (HN 2)

• ​Life on Venus - Deep Dive (2020)​

• ​Astrophotography by Panagiotis Andreou​

• ​Elon Musk at 2020 Mars Society Event​

• ​Fermi paradox: why haven’t we found aliens yet? (2018) - New paper on the Fermi paradox convincingly shows why we will probably never find aliens.

• ​NASA Asteroid Sample Return Mission​

• ​Big Trouble in a Deep Void (2020) (HN)

• ​AstroWright - Astronomy and meta-Astronomy by Jason Wright.

• ​How to survive in spacecraft (2020) (HN)

• ​Akin's Laws of Spacecraft Design (HN)

• ​Avi Loeb: Aliens, Black Holes, and the Mystery of the Oumuamua (2021)​

• ​Professor Abraham (Avi) Loeb Research​

• ​ARK Space Exploration ETF (ARKX) (2021)​

• ​AstroBin - Image hosting platform and social network for astrophotographers. (Code)

• ​NASA - US National Aeronautics and Space Administration.

• ​NASA Jet Propulsion Laboratory (JPL)​

• ​Virgin Galactic - American spaceflight company.

• ​Once we can see them, it’s too late (2021) (HN)

• ​Ask HN: What entry level telescope should I choose? (2021)​

• ​If Aliens Exist, Here’s How We’ll Find Them (2021) (HN)

• ​Mars Is No Earth (2021) (HN)

• ​Spaceprob.es - Catalogs the active human-made machines that freckle our solar system.

• ​Low Earth Orbit Visualization (HN)

• ​Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky (2021) (HN)

• ​Setting Up Starlink, SpaceX's Satellite Internet (2021) (HN)

• ​Inspiration4 - Planned SpaceX Crew Dragon mission to low Earth orbit.