A blazar is an active galactic nucleus (AGN) with a relativistic jet (a jet composed of ionized matter traveling at nearly the speed of light) directed towards an observer.

Blazars are powerful sources of emission across the electromagnetic spectrum and are observed to be sources of high-energy gamma ray photons.

Blazars are highly variable sources, often undergoing rapid and dramatic fluctuations in brightness on short timescales (hours to days).

In 2009, a team of astronomers using the Swift spacecraft used the luminosity of S5 0014+81 to measure the mass of its super-massive black hole. They found it to be about 10,000 times more massive than the black hole at the center of our galaxy, or equivalent to 40 billion solar masses

  • Pons_Aelius@kbin.social
    251·
    1 year ago

    The counter-intuitive part of super-massive blackholes is that because the event horizon (point of no return) is so large it is possible to cross it without yet suffering any obvious effects. You are “alive” (for a while) passed the point of no return but will never be seen by the rest of the universe again.

    Where as with smaller black holes the rate of gravity increase at the event horizon it much. much higher. This means you would be dead before crossing.

    • kameecoding@lemmy.worldEnglish
      61·
      1 year ago

      couldn’t you theoretically time travel forward by getting close to this super massive backhole changing out for a while then leaving, assuming you have the technology to do the leaving part

      • Pons_Aelius@kbin.social
        91·
        1 year ago

        IIRC: Time dilation does kick in if you orbit very close to the event horizon but this is more to do with the fact you would have to be travelling at a reasonable percent of the speed of light to do so than is does the black hole.

        Ie: you would get the same time dilation travelling at the same speed in a straight line.

        But once you cross the event horizon, there in nothing in our current understanding of physics (including using wormholes etc ) that can bring you back.

        • kameecoding@lemmy.worldEnglish
          3·
          1 year ago

          Stargate led me to believe the strong gravitational forces of the blackhole would affect how fast time passes, meaning the closer you get to a blackhole the less time it elapses for you compared to people observing from afar not affected by the gravitational forces.

          • Pons_Aelius@kbin.social
            67·
            1 year ago

            Stargate, while a good series, is not the place to go for accurate information on astrophysics.

            Intense gravity does not cause time dilation. This only happens when a mass is accelerated to a relativistic velocity.

            This is the equation to calculate time dilation:

            Time dilation factor = the square root of (1 - (v2/C2))

            v = velocity of the mass.

            C = speed of light.

            The only thing that affects time dilation is the velocity of the mass compared to the speed of light.

            The gravity affecting the mass is irrelevant.

            It sounds like the stargate writers were told “Orbiting close to a black hole can cause time dilation” but what they heard was “being close to a black hole causes time dilation, black holes have high gravity…therefore being in a strong gravity field causes time dilation”