Black holes

what is escape speed and what does it mean?

Escape speed is the minimum speed needed to launch an object from earth so that the object will never fall back, earth’s escape speed is 11 km/s and the sun’s is 42 km/s

what is orbital speed?

Orbital speed is the speed an object needs to achieve in order to maintain a stable orbit around a celestial body, balancing gravitational pull with its inertia. It varies depending on the mass of the body being orbited and the distance from it.

what is Vorb and Vesc?

V_orb is the speed of a satellite to stay in orbit around earth/any planet and V_esc is the speed needed to escape the gravity and break from the orbit, if the speed of a satellite is increased around 1 and ½ times the orbital speed, then the satellite will will escape the gravity of the planet

what is einstein’s theory of relativity?

it’s impossible to tell from within a closed system whether one is in a gravitational field or accelerating, einstein thought gravity is an acceleration in space-time fabric

explain spacetime

Spacetime is a four-dimensional continuum that combines the three dimensions of space with the dimension of time, providing a framework for understanding how objects move and interact under the influence of gravity

what are analogies for spacetime?

Analogies for spacetime include the surface of a trampoline representing gravitational fields that warp space, and the idea of a fabric that can be stretched and curved by mass.

how do we test einstein’s theory of general relativity?

deflection of starlight by the sun’s gravity was measured during the solar eclipse of 1919 & the results agreed with the predictions of general relativity , confirming that light follows the curvature of spacetime created by massive objects.

what is gravitational lensing?

when light bends as it passes by massive objects, in extreme cases we can observe the light coming from multiple places or bent into an einstein ring

can we escape the black hole?

No, once inside the event horizon, escape is impossible due to the immense gravity.

what is an ergosphere?

a region outside the event horizon where gravitational forces start to influence object movements, objects here can’t be stationary in space

depending on the distance between object & event horizon, the influence can be extremely strong or weak

what happens close to the horizon?

close to the event horizon, where escape velocity is nearly the speed of light, gravitational force will rip objects apart & eventually draw most of their material in

what is the schwarzchild radius?

The boundary surrounding a black hole beyond which nothing, not even light, can escape due to the extreme gravitational pull. It marks the point of no return for objects falling into the black hole, it’s the critical radius at which the escape speed = c

what is the event horizon?

the imaginary surface of a sphere with the schwarzchild radius and is the limit of how close you can approach the black hole & still escape

what’s inside of a black hole?

theories predict that the mass collapses until its radius is 0 and density is infinite but it’s a mystery

how do GPS satellites use time dilation?

general relativity predicts that clocks go slower in a higher gravitational field that is the clock aboard the GPS satellites that clicks faster than the clock down on earth and special relativity predicts that a moving clock is slower than the stationary one

what is a wormhole?

a theoretical passage through space-time that could create shortcuts for long journeys across the universe, they might be wary: warmholes bring the dangers of sudden collapse, high radiation and dangerous contact

what is time dilation?

Time dilation refers to the phenomenon in which time passes at different rates for observers in different gravitational fields or moving at different velocities. It is a key concept in Einstein's theories of relativity.