• The Milky Way galaxy contains 30 total galaxies.
  • Three of them are on a collision course.
  • GAMA RAY BURSTS might wipe out all life in its host galaxy. That now seems pessimistic because the latest evidence shows that GRBs focus their energy along two narrow beams like a lighthouse might do on Earth, rather than exploding in all directions like a bomb.
  • The most influential events in the known universe—gamma-ray bursts (GRBs)—are short-lived outbursts of high-energy light. They can erupt with a quintillion (a ten followed by 18 zeros) times the luminosity of our sun. Now, I thought about announcing the births of new black holes, but they were discovered by accident.
  • A neutron star can become a black hole if it gains enough mass. Stars whose birth masses are above roughly 8 to 10 times the mass of our sun.Neutron star crust is the strongest material in the universe.
  • The supernova occurs only if the core’s mass is above 1.4 solar masses. If the mass is below this, there will be no supernova; the core will be a white dwarf. A dying star mostly turns into a black dwarf.
  • Cosmic superstructures hold mass together.
  • Galactic Walls. These walls are likely the most extensive known superstructures within the observable universe. They can stretch hundreds of millions of light-years across but are relatively thin—only about 20 million deep. Galaxy clusters are the most significant objects in the universe held together by gravity. They contain hundreds or thousands of galaxies, lots of hot plasma, and much invisible dark matter.
  • Galaxy clusters are the most significant objects in the universe held together by gravity. They contain hundreds or thousands of galaxies, lots of hot plasma, and much invisible dark matter.
  • A cosmic void is a large, low-density region of space in the universe that contains few or no galaxies. It can be millions of light years across, much larger than the Milky Way galaxy, which is only 100,000 light-years across. Cosmic voids (dark space) are vast spaces between filaments (the largest-scale structures). The void differs from the vacuum space of our universe because it has “nothing” in it—no space, time, mass, or charge. It only has pure energy (in the universe) that contains very few or no galaxies
  • Most starbursts are caused by collisions or near passes with other galaxies. These interactions push the gas in the galaxy toward the center, where it reaches sufficient density to induce star formation. After a core-collapse supernova, all that remains is a dense core and hot gas called a nebula.
  • From largest to smallest, these terms are:
  • . The universe,
      • Planest.
      • Moons.
      • Asteroids.
      • galaxies, solar systems, stars, 
      The end?
    • Big Freeze or Heat Death.
    • Big Rip.
    • Big Crunch.
    • Big Bounce.
    • Cosmic uncertainty.
    • ONLY TO BEGIN AGAIN.
  • Quasars are a subclass of active galactic nuclei (AGNs), extremely luminous galactic cores where gas and dust falling into a supermassive black hole emit electromagnetic radiation across the entire electromagnetic spectrum.
  • A quasar is about 3.4 billion light-years from Earth.
  • It is a rare and extreme class of supermassive black holes furiously pulling material inwards, producing intense radiation and sometimes powerful jets. A quasar is an astronomical object of very high luminosity found in the centers of some galaxies, powered by gas spiraling at high velocity into an extremely large black hole.