hello my friends and dear astronomers
we will speak about blackhole and its news in this topic
if you have any question or any idea about the blackhole please share it
:you're kidding, rig
نمایش نسخه قابل چاپ
hello my friends and dear astronomers
we will speak about blackhole and its news in this topic
if you have any question or any idea about the blackhole please share it
:you're kidding, rig
of course i know that all of you are familier with blackhole's concept and its extraordinary traits
but i have a question of you ?
in your idea, a blackhole can has a distance ?!!
for example you can measuring high and width of a thing !!!
can you do it for a lovely blackhole ?
!!!!!!!!!!!Hi there
Dear x-blackhole , I think u should give us some primary information about definition of :yaeh%20am%20not%20dblackholes at first
But it doesn't matter I explain it & give an introduction of blackholes:killzonesmiley:
?What is a blackhole
Most people think of a black hole
as a voracious whirlpool in space, sucking down everything around it. But that’s not
really true! A black hole is a place where gravity
has gotten so strong that the escape velocity is faster
than light. But what does that mean, exactly?
A black hole is formed when a star of sufficient mass undergoes gravitational collapse, with most or all of its mass compressed into a ufficiently small area of space, causing infinite spacetime curvature at that point (a "singularity"). Such a massive spacetime curvature allows nothing, not even light, to escape from the "event horizon," or border.
Black holes have never been directly observed, though predictions of their effects have matched observations.
How do black holes form
The most common way for a black hole to form is
probably in a supernova, an exploding star. When a star
with about 25 times the mass of the Sun ends its life, it
explodes. The outer part of the star screams outward
at high speed, but the inner part of the star, its core,
collapses down. If there is enough mass, the gravity of
the collapsing core will compress it so much that it can
become a black hole. When it’s all over, the black hole
will have a few times the mass of the Sun. This is called
a “stellar-mass black hole”, what many astronomers
think of as a “regular” black hole.
What happens when you fall into a black hole?
If you fall into a black hole, you’re doomed. Sure, once you fall in you can never get
back out, but it turns out you’ll probably be dead before you get there.
The gravity you feel from an object gets stronger the closer you get. As you approach a
stellar-mass black hole feet-first, the force of gravity on your feet can be thousands of times
stronger than the force on your head! This has the effect of stretching you, pulling you apart like
taffy. Tongue-in-cheek, scientists call this “spaghettification.” By the time you reach the black hole,
you’ll be a thin stream of matter many miles long. It probably won’t hurt though: even falling from
thousands of kilometers away, the entire gory episode will be over in a few milliseconds
of course :t5hq2u: it's a resume of blackhole's definition
A black hole is a region of space from which nothing, not even light, can escape. It is the result of the deformation of spacetime caused by a very compact mass. Around a black hole there is an undetectable surface which marks the point of no return. This surface is called an event horizon. It is called "black" because it absorbs all the light that hits it, reflecting nothing, just like a perfect black body in thermodynamics.[1] Quantum mechanics predicts that black holes also emit radiation like a black body with a finite temperature. This temperature decreases with the mass of the black hole, making it difficult to observe this radiation for black holes of stellar mass.
Despite its invisible interior, a black hole can be observed through its interaction with other matter. A black hole can be inferred by tracking the movement of a group of stars that orbit a region in space. Alternatively, when gas falls into a stellar black hole from a companion star, the gas spirals inward, heating to very high temperatures and emitting large amounts of radiation that can be detected from earthbound and Earth-orbiting telescopes.
Astronomers have identified numerous stellar black hole candidates, and have also found evidence of supermassive black holes at the center of galaxies. In 1998, astronomers found compelling evidence that a supermassive black hole of more than 2 million solar masses is located near the Sagittarius A* region in the center of the Milky Way galaxy. Recent results indicate that the supermassive black hole is more than 4 million solar masses.
and if u want to catch more information go to :
http://en.wikipedia.org/wiki/Black_hole
U can open this file there are pics on it of blackholes..but u konw i think they aren't real
I want to take the first picture of a black hole
07 February 2012 by Jon White
__________________________________________________ ___________________________________
Images of a black hole could test general relativity as well as prove they exist, says astronomer Dan Marrone *
http://www.newscientist.com/data/ima....300-1_300.jpg
[Marrone and his team are hoping to take the first picture of a black hole in 2015 (Image: Jorge Vieira)]
A black hole, by definition, is black. So how are you going to take a picture of one?
If you look right at the black hole it should look quite dark, as very little light escapes. But just around the edge of it you see a bright ring, which is due to the photons that barely missed going into the black hole and skimmed around the edge of it a couple of times. This light is what we think we will be able to detect with the Event Horizon Telescope (EHT).
The EHT is a "whole Earth telescope". How does it work?
In radio astronomy, to get a higher resolution than you can from a single telescope, you record signals from many telescopes around the world and multiply them together with a special computer. It is as if you have a single telescope almost the size of the Earth.
Which black holes are you targeting?
Sagittarius A*, which is the supermassive black hole at the centre of our galaxy, and the black hole at the centre of M87, the biggest galaxy in the Virgo cluster of galaxies. With a telescope the size of the Earth and at the frequencies we are observing, we can just make out black holes of this size.
Every image of a black hole so far has been an artist's impression. Will the real thing match expectations?
The question of creating an image from what we measure is a tricky one. We will most likely represent it as a false colour image, using colours to represent how bright the light is. This image will not be as pretty as an artist's impression. The galaxy blurs the light between us and the black hole, so there are a lot of sharp features we can't possibly see. But any image we get shouldn't disappoint - we are looking at something no one has ever seen before.
What about capturing a moving image - "black hole, the movie" as it were?
We can, if there is something orbiting the black hole, as we expect there will be. If there is gas orbiting before it falls into the black hole, this takes between 4 and 27 minutes, depending on the spin of the black hole. If we look for several days and see changes in the structure, we can represent that as a movie as well.
What are you hoping to learn from this image?
Just being able to take a picture of a black hole, and show this shadow that we expect to be there because the light is not escaping, will be important. Beyond that we have a lot to learn about the structure of our galaxy's black hole, and what happens to a black hole when it is being starved of material, as Sagittarius A* appears to be.
We also expect to be able to test general relativity, which tells us that the ring of light around the edge of the black hole needs to be perfectly circular. If general relativity is breaking in this very strong field regime, where gravity is at the limits of its power, then this ring of light won't be perfectly circular.
*(Profile: Dan Marrone is an astronomer at the University of Arizona Steward Observatory. He is part of the Event Horizon Telescope programme, inaugurated last month, which aims to take the first picture of a black hole in 2015)
From: NewScientist
I think one of the best objects in the universe are black holes In the past I was afraid of the black hole but when I realized that After the death of stars, black hole is create I've changed my opinion because it's very exciting and I think imaginable
this is link of short clip about black hole:
http://www.faupload.com/upload/90/Ba...ing-a-star.flv
And there is another text by Clay Dillow which posted on 02.16.2012 , about :
"How to take a picture of a black hole"
http://www.popsci.com/files/imagecac..._Facility.jpeg
ALMA Prototype Radio Antennas ALMA (ESO/NAOJ/NRAO)
You can check it here too: http://www.popsci.com/technology/art...ure-black-hole