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Astrophysics
Astrophysics is the scientific discipline concerned with the events that are taking place on the grandest of stages; the universe. Questions about the formation and evolution of the planets, solar systems, stars, and galaxies found within the universe, as well as questions regarding black holes, cosmic rays, particle and nuclear astrophysics, nucleosynthesis, and magnetohydrodynamics should be directed here.
1,304 Questions
What technology helped scientists learn about quarks?
The quark model was independently proposed by Murray Gell-Mann and George Zweig in 1964. This was well before computers were powerful enough to analyze any data from particle accelerator collision observations (the CDC 6600 supercomputer was just introduced that year).
The devices for making these observations at the time were cloud chambers, bubble chambers, spark chambers, etc. and photographs of the trails were taken and visually analyzed by humans.
It probably was not until the late 1960s when minicomputers became widely available that data from more advanced detectors could be collected and the data disks or tapes taken to large scientific mainframes for computer analysis.
So the actual technologies used to develop the model were:
- particle accelerators - e.g. van de graaff machines, cyclotrons, synchrotrons, betatrons
- detection devices - e.g. cloud chambers, bubble chambers, spark chambers
- photography
- measurement tools - e.g. protractors, length scales
- electromechanical calculators
- etc.
Is black hole a 3D shaped object or 2D shaped object?
A black hole is not a hole, it is a sphere. The ultra-dense collapsed core of a now dead star.
It exists in three physical dimensions, like all objects in the universe.
It exists in space-time, like all objects in the universe.
Black holes do not "suck everything in." The normal laws of gravity still apply to it. You can measure its mass. If you are any random distance away from its center, there is a specific velocity you can travel perpendicular to that black hole, to maintain a stable orbit.
The difference between a black hole, and everything else is, it is so dense, that if you get close enough to it, the escape velocity exceeds the speed of light. Nothing can orbit or escape it at that distance, no matter how fast you travel.
"Delta" - the uppercase Greek letter delta, which looks like a triangle - is often used in the sense of "difference". You are simply supposed to calculate the difference between two different values of "v" (where "v" might stand for the velocity).
It doesn't work like that. A black hole doesn't expand, unless its mass increases, i.e., when additional matter falls into it. And there is no place where its gravitational pull stops - the gravitational pull goes all the way to infinity (just as in the case of any other mass).
Will the universe end in rust?
No. No one is sure how the universe will end but probably but expanding until all parts are far away from each other, and moving too fast to allow light to reach any one part from any another.
Is the Pisces constellation close to a black hole?
What we call Pisces is an "area" of the sky, a direction, and in that direction there are numerous objects that most probably contain black holes. Among these is 3C 31 is an active galaxy and radio source located at a distance of 237 million light-years from Earth (redshift 0.0173). Its jets, caused by the supermassive black hole at its center, extend several million light-years in both directions, making them some of the largest objects in the universe.
Is a black hole a living organism?
No. Black holes are huge stars that have collapsed so far that their force of gravity is so enormous that even light cannot escaple. (Hence, they are 'dark' )
What factor makes a black hole invisible?
According to the leading theories, it is the relativistic distortion of space/time around a singularity that prevents us from seeing a black hole directly. Light follows the curvature of space. Space curves due to gravity (or more apt perhaps is the statement that gravity *is* the distortion of space). Space around a singularity of sufficient mass is curved to such an extent that a ray of light, once entering the region of curved space surrounding the singularity, is forced to either spiral inwards towards the singularity or follow a circular path around the singularity, never to exit that region again. Since no light can escape from the region surrounding the singularity, the singularity itself can not be seen. The demarkation between the region where light is just barely able to escape the relativistic distortion and where it is not is called the 'event horizon'.
How does Stephen Hawking's theory of the black hole affect us today?
Stephen Hawking's theory of black holes has greatly advanced our understanding of these mysterious phenomena. It has influenced research in astrophysics and helped reveal new insights into the nature of space and time. Additionally, his work has sparked new ideas and avenues for studying the fundamental laws of the universe.
How old is the sun in the milky way solar system?
The sun in our Milky Way solar system is about 4.6 billion years old. It formed from the gravitational collapse of a region within a large molecular cloud and has been shining for over four billion years.
How long does it take after a star goes supernova does it become a black hole?
The supernova stage itself lasts only a few days or weeks. Once the star runs out of fuel, the collapse into a neutron star or black hole (depending on the remaining mass) should be quite sudden - whatever it takes for matter to fall toward the center.
Is a black hole strong enough to suck earth in?
If a black hole came close to our Earth, it would most definitely suck it in. But we wouldn't have much to worry about, since the x-rays radiating from the accretion disk surrounding a black hole would kill all life on our planet long before the black hole got here.
Can dark energy counter a black hole's gravity?
No, dark energy and black hole gravity are two separate phenomena that do not directly interact with each other. Dark energy is a theoretical form of energy that is thought to be causing the accelerated expansion of the universe, while a black hole's gravity is a result of its mass and curvature of spacetime.
Why are you not in danger of being sucked into a black hole?
Because the nearest one is 1600 light years away.
Even if someone traveled at 80% of the speed of light towards there, it would be two millenia before s/he got there.
Do the laws of physics break down at the singularity because infinity cant be properly explained?
Correct!
What is black hole how can it be felt when it is not at all visible?
Bassically a Black Hole is created when a certain type of star collapses in on its self because of its own gravity, condencing all of its matter to a point contained within the space of an atom. Some Black Holes have the mass of billions of stars the size of our sun.
Even though they are the size of an atom - actually smaller - and are called a 'singularity' they still have the same mass as that sun, or numerous suns, so still have the same 'spacial effect' because of their gravity on objects as they would have if 'uncollapsed'. Just as the Sun effects the earths rotation, if the sun collapsed to a singularity it would still have the same effect on the earths rotation (not that the sun will collapse to a singularity, or Black Hole - it is too small).
First, so called black holes are not holes at all. They are collapsed stars of extreme density - think of it as a tiny planet with extremely powerful gravity. Second of all, they aren't exactly proven to exist at all - we merely assume that what we discovered are black holes, given their powerful gravity and lack of light in the area. They could be alien spacecrafts, or portals to a parallel universe, as far as science knows. Anything is possible in deep space. Since black holes aren't exactly holes, they don't have a "bottom"
Second of all, they are not black. Their gravity is so powerful, that not even light can escape it. By such, they pull all the light in the area inside of them, thereby making themselves seem black. The event horizon is the point of no return - when something goes past it, it's not possible for it to leave the gravitational pull of a black hole unless it went faster than light - which, as Einstein claimed, is impossible.
No one knows what would happen to anything that would be pulled inside a black hole (if they do, in fact, exist). Most probably the object would be crushed with gravity.
What are the chances that the sun will turn into a blackhole?
Absolutely zero. Our Sun does not have enough mass to explode as a supernova and it is those details that are required to make a black hole.
What band of radiation is best for studying black holes?
X-rays are the best band for studying black holes as the radiations emitted by the black hole is X-rays so we can expect the presence of a black hole anywhere in the Universe.
Why do planets orbit the sun at different distances?
The planets formed from a disk of gas and dust that surrounded the sun as it formed. This gas and dust clumped together to form the solar system. Two planets cannot occupy orbits that are too close together. If they do, interactions through gravity will either cause them to collide or get moved to different orbits.
Do all the galaxies form a bigger galaxy?
Over time - billions of years - galaxies will merge with other galaxies. In about 3 billion years, the Andromeda galaxy will merge with our own galaxy, the Milky Way.
However, the separation between galaxies is so great, that not all galaxies will merge unless the fundamental issue of the amount of mass in the Universe is determined.
If we live in a "contracting universe" then eventually all galaxies will merge.
How much water is there on each planet?
- Mercury: Very little water, mostly in the form of ice in shadowed craters.
- Venus: There is minimal water vapor in the atmosphere, but no liquid water on the surface.
- Earth: Abundant surface water in oceans, lakes, and rivers.
- Mars: Some water ice and evidence of past liquid water, but present water is scarce.
Can the moon become a black hole?
No. The moon cannot become a black hole. A black hole is formed when a star1 collapses in on itself. But not all collapsed stars become black holes either, in fact, only a small percentage do. The majority of them become novas or supernovas. The moon is way too small and inactive (cold "dead" rock2) to expand or contract as a star does so, no it cannot become a black hole by itself (it can be absorbed into one if one ever comes close enough.)
1 composed of hydrogen, helium, oxygen, nitrogen, and and carbon (nothing more complex)
2 composed of light rock - mostly the ores of orthopyroxene, clinopyroxene, and olivine, including ilmenite and ferrite (iron and titanium.)
