It`s nearly a billion light years across Kingnuuur, a hole, where nothing exists. Black holes are formed when massive bodies such as stars implode due to the forces of their own gravity (which you know, I`m just trying to work things out).

I`ve just read, some of the largest black holes could have a mass of 18 - 50 billion suns


Newscientist quote;

Even a black hole at the lower end of this range would be gargantuan - more than 3 times as wide as our solar system.


(Pluto’s average orbital distance is 5,900,000,000 km from the sun -5.9 billion).

(One light year = 9,454,254,955,488 km)

So light could take 1000 minutes (16.6 hrs) to travel an area this size ?

Edit; 5.9 is average distance from sun, so x2 for width of our solar system(not including The Kuiper Belt or Oort cloud).
Which makes it over 33hrs and not 16.6.
Puts a light year in perspective then, a distance of a billion light years is unimaginable.

Did you major in physics, Kingnuuuur?

Probably not, since he thought about absurdly large black holes and didn't recognize this:

http://en.wikipedia.org/wiki/Void_(astronomy)

Napero is correct, I didn't major in physics.

In my defense, with present knowledge the nature of this hole remains unknown. It could be a void, or something entirely different.

Or, to be honest, it could be an observation anomaly, the methods used in its detection are arguably not the most accurate things there are. At least I think I read something like that somewhere.

Heh, my mistake. I'm glad you brought up the Heisenberg Uncertainty Principle. Probably once of my favorite theories in physics. It explains A LOT.

got me thinking

If black holes can be this size, maybe we`re inside one?

Black holes containing Universes which have black holes containing universes..



maybe not so absurdly big after all?

After rereading my post about black holes and time, I realized that I messed up something fundamental. I've written that redshifting makes everything approach a constant. But in fact, it depends on where the frequency parameter is placed in an equation. My example with sound is correct, while the one with light is not quite correct.

To keep things simple, sound is composed of mechanical waves with a frequency of f. The equation for f is:
where T is the amount of time it takes to complete one cycle. What redshifting essentially does is make T continuously bigger. Approaching the event horizon, the redshift effect approaches infinity, therefore T approaches infinity. As a result, f approaches the limit of 0 Hz. Correct!

With light and wavelength, it's different. Light is composed of photon particles behaving like a wave. The wavelength, which relates to the photon's amount of energy, is written as λ and its equation is:
where c is the speed of light in vacuum and f is frequency again. Since we saw that f approaches 0 Hz in a black hole, then λ will approach infinity. I was inaccurate in stating that light gets pushed to the infrared portion of the EM spectrum. Rather, it gets pushed to the radio portion and beyond. Therefore its wavelength approaches infinity, not a constant.

But then if a wave becomes infinite in length, doesn't that mean that it no longer represents a wave in the physical sense, but a line? This nullifies the electromagnetic oscillation and makes the photon's energy approach 0 J, which explains why light cannot escape from a black hole and eventually disappears, according to our distant readings. To further prove this:
This is the Planck-Einstein equation which relates frequency (v) with energy. Since v approaches 0 Hz and h is a constant, then E approaches 0 J.


I don't know, I haven't looked into that theory to be honest.

Hey I'm wondering, what's the official position on the asteroid Apophis? Is it going to hit us or not? I've read that the closer the asteroid gets, the more scientists realize that the chances of it hitting us gets less. However, I have heard from several people that it all depends on a sort-of gravitation keyhole (I believe that's what its called). However, I've heard that even that is unlikely.

So whats the official position on it?

You can read all the details in a recent post on astronomer Phil Plait's blog (in which he takes apart a crappy Russian news story about it), but the short of it is the following.

Apophis is a near-Earth asteroid about 250 meters long that passes relatively near us every 7 years or so. On April 13th 2029, it will pass very close to Earth (below our geosynchronous satellites!) but will not hit us. At that time though, if it goes through a specific region of space, indeed called a keyhole, its orbit will be modified so that it will hit our planet 7 years later in 2036. The chances of that happening are extremely slim though; astronomers don't know the orbit of Apophis precisely enough to know for sure it won't pass through the keyhole, but they calculate the chances of that happening to about 1 in 135,000, or 0.0007%.

There is really very little to be worried about.

Just for fun though, I'll point out that if it does hit, a rock 250m long would explode with an impact of roughly 900 megatons; that's a dozen times the yield of the largest nuclear weapon ever detonated. For comparison, the Tunguska event, which you might have heard of, was most likely 10-15 megatons, or about 1000 times the power of the Hiroshima atomic bomb - and that rock didn't even hit the ground, that's all from the airburst of its explosion in the atmosphere. Can you imagine what the extent of the destruction caused by Apophis would be?

But yeah, don't worry about it.

I think its amazing that when I was in 3rd grade in 89/90, we studied the solar system and used to think that that was all there was. A few years ago, they found another planet... now, finding a new one is almost daily.

When the asteroid does pass us, will it be close enough for us to view it? That could be quite a sight.


So...your saying there's a chance?

Kidding. How fucked would it be if it actually hits us with those kinds of odds.


I have heard of the Tunguska event, and I have to say that when I first heard that story, I was simply amazed by the sheer power of an asteroid.

As for Apophis, if it would hit us, that just sounds like the end of existence as we know it. However, I heard that it would land somewhere in the Pacific Ocean, which would cause giant tsunami waves which would ravage a few areas, but nothing too catastrophic to the point that life as we know it would cease. Is that the case?

According to Wikipedia, the "close approach will be visible from Europe, Africa, and western Asia" and would be "visible to the naked eye from rural as well as darker suburban areas," and "with binoculars from most locations." No doubt you would only see a point of light without a telescope though.



Heh. Actually, Wiki states "as of October 7, 2009, the impact probability for April 13, 2036, is calculated as 1 in 250,000." So possibly Phil's figure was already outdated and there's even less chance of impact. Wiki also says that "an additional impact date in 2068 was also identified; the impact probability for that encounter is calculated as 3 in a million." Apparently we might be able to get better measurements of the asteroid's orbit during a close approach in 2013, which should allow predicting its exact location out to at least 2070.



Ah, I see that NASA has apparently revised the estimated impact strength down to 510 megaton, which is still not very reassuring. I found this image of the estimated 2036 path of risk, I don't think it's possible to predict exactly where it would hit at the moment.



So there's a lot of water, but also some land in there. Still from Wiki: "the exact effects of any impact would vary based on the asteroid's composition, and the location and angle of impact. Any impact would be extremely detrimental to an area of thousands of square kilometres, but would be unlikely to have long-lasting global effects, such as the initiation of an impact winter." Also, "using the computer simulation tool NEOSim, it was estimated that the hypothetical impact of Apophis in countries such as Colombia and Venezuela, which are in the path of risk, could have more than 10 million casualties. An impact several thousand miles off the West Coast of the US would produce a devastating tsunami." So in short, not the extinction of humankind, but still devastation on massive scales.

In 1977 Dr. Jerry R. Ehman detected a signal while working on a seti program at the Ohio State University Radio Observatory (Big Ear). What was it`s origin? An anomaly? Earth bound reflection off space debris - Military?

Honestly, I think it might be something like this.

Cthulhu lives there. No, but I think that you would pierce into the infinite region of space where all the different "multi-verse bubbles" co-exist if you don't touch past a region that's connected to another "universe" in the first place. I'm probably wrong though.



Your forum friend was probably referring to this. It's an interesting theory that makes for nice cartoons and sci-fi Kung Fu movies. David Icke's probably supplanted his material with this too. Please excuse my skepticism...I guess I just find it difficult to accept the idea that you might actually be a unicorn living in a world of horse sex and telepathy (since you wouldn't have fingers to use a computer). If that was the case (since objective reality is imaginary), then why did I imagine her like that and not, say, any other number of things? The human brain is basically a blank slate in the beginning and exterior circumstances shape one's perceptions, which is coupled with the individual's personal will so...somebody else definitely has a reality that concurs with mine. If you assert there is no such thing as objective truth, aren't you contradicting yourself?

Going back on track...

Is this evidence of extraterrestrial life found in a meteorite? Maybe. I am very curious to see what those expert reviews will say about the paper.



EDIT: Phil just posted a follow-up. It seems the first opinions coming in from other scientists are not very enthusiastic about the credibility of this discovery. Pity.

Let's bump this thread with some recent cool news.

On March 17th, NASA's Messenger probe become the first spacecraft to orbit Mercury. Its formal science data collection mission will begin on April 4th, and is scheduled to last 12 months.

On March 19th, NASA's New Horizons mission en route to Pluto crossed the orbit of Uranus at about 2.9 billion kilometers from Earth. This is one of the final milestones on its voyage before passing by Pluto in July 2015.

Also from this month is a new picture of exoplanet Beta Pictoris b. Here is a montage of three different images, showing the planet moving along its orbit over time (with Saturn's orbit shown on the same plane for comparison). There are more details on the ever informative Bad Astronomy. This is pretty cool stuff; I can't wait until we have telescopes capable of imaging these exoplanets more clearly.

From: http://thetechjournal.com/science/nasa-discovers-arsenic-born-organisms.xhtml

I thought that this article was pretty cool. Organisms that naturally use Arsenic in their genetic molecules instead of Phosphorous. This is a huge leap towards finding extraterrestrial life!

Nasa posts new "WISE" photographs.

http://www.nasa.gov/wise

Decided to put on an episode of the series BBC - Space - which i havent watched in a while. I know this is pretty rudimentary stuff to some of the people in this thread - but this is still i think a really well done, sleek documentary for intorductory puropses - documentaries are always pretty rudimentary anyway, compared with texts, primary sources and journal articles, but yeah. Presented by Sam Neil (who always rules), it's well narrated, and the graphics side of things is really nice and clear. I'm watching episode 3 - the Black Holes one. I have read up on this stuff before, and watched documentaries but i still find this stuff hard to comprehend - maybe it's because of their unfathomable nature, or perhaps i'm just an idiot (most likely the latter). I don't understand how they can make statement like "There are about 10 million black holes" or "Black holes have all this mass but are no bigger than a pea" - i really don't get how the can make such sweeping, and detailed claims. Sure i've heard all this stuff before, and even llooked into how they discovered them, but i still can't really comprehend how they measure these things and find out this data.

I like most people in this thread like checking out Bad Astronomy, so you've probably already seen these. But these videos of an explosion on the sun pretty much stunned me, so I figure everyone should have a gander.

http://www.youtube.com/watch?v=Hyi4hjG6 ... r_embedded - This one just looks cool, shows to scale of it too.

http://www.youtube.com/watch?v=LpkXhlPI ... r_embedded - This one doesn't terrify me as much, but it has cool details like the possible shockwave flowing along the surface/things falling back in on the sun. Very cool.

At risk of sounding like an huge stoner, "A Glorious Dawn" is AMAZING to get high and listen to, especially on a warm summer night. Though apparently Carl Sagan was quite the pot fan himself.

Neutron stars are amazing. The density of a few dozen suns in something smaller than earth. What would a hunk/cloud of neutronium even look like?

What about black holes? It's the next step. If the Sun was to be one, it would be the size of a tennis ball.

I*'m somewhat interested in space colonization anyone have any comments on that?

Unless we can fill Mars of impervious installations and get outside only in suits (can't see the interest besides a scientific one), we won't see that in our lifetime, if at all. Considering how damn far is the closest star to ours (and if there is an habitable planet), going there would probably be impossible. Unless we develop some crazy new technology, but I sincerely believe it simply can't happen.

We actually had a whole thread about it a while ago, I think it's a neat idea, but it would be hard to make it a reality. Plus, I doubt NASA feels like pouring money they don't have into a "neat Idea."

The most interesting size for a black hole is the Schwarzschild radius, which marks the radius of the event horizon. The Sun has a Schwarzschild radius of ca 3 km so I take it your tennis court is quite enormous. Using a regular sized tennis ball as Schwarzschild radius, a quick calculation gives that the corresponding black hole would have a mass approximately equal to four Earth masses.

On another note, magnetars are the most awesome kind of neutron stars.

Now you delve into stuff I barely know about... But still, I guess this stuff is pretty surprising and interesting, as always. Don't know of magnetars either, I'll have to find some book on the subject. I'm also considering studying astrophysics at uni.

Hawkwind! I hope I'm right

I love how metalheads are often into this deep and meaningful stuff. As a wannabe astrophysicist this thread warms my heart

Actually one of my professors is part of the team who recently were able to confirm that dark energy is the reason the universe's expansion is accelerating (confirming general relativity isn't bunk).
The concept of a mysterious substance that we can't see or sense being responsible for, what is it, 70% of the matter in the universe? is kinda crazy to me, but apparently that's physics...



Magnetars are indeed the shit. Producing magnetic fields on the order of gigatesla when the strongest we can create on Earth is 8 tesla or something. Neutron stars in general are fascinating.
I read that a few years back there was a starquake on a magnetar that would have measured 32 on the Richter scale - insane!

I love space.

From the outside looking in; its always appeared to me that dark energy is just a convenient moniker for forces that we don't have a inkling about

So you don't think it sounds like physicists just making shit up? That's comforting. Although a lot of good things have come out of creatively explaining something *then* going looking for evidence to back it up.
I hope they get an inkling of what Dark Energy/Matter is within my lifetime.


Back on the subject of black holes though - most people talk of the singularity, but have you heard of Kerr black holes? They rotate, and so the singularity is actually ring-shaped. Basically, if you happened to fall into it, rather than getting all spagettified and dead (or who knows really), it should theoretically be possible to go through the ring. Which might be a wormhole, which might spit you out in a different universe.

... wha- ?

http://news.nationalgeographic.com/news ... e-science/

ehh..... based on the magnetic clusterfuck on the surface of the sun its not surprising that its oddly shaped out on the edge of the solar system

Interesting. Why would that be? I really don't know much about the physics of space (took Astronomy and Cosmology, but never anything with math).

I wonder why they theorized it to be smooth in the first place if it's more likely to be odd like you say?

No, you'd still die. The shape of the singularity has nothing to do with the tidal forces you'll experience on your way in.



This isn't actually unique to the ring, you get similar behavior in Reissner-Nordstrom (that is charged and non-rotating) black holes which have a point singularity. The behavior comes from the fact that these solutions have both outer and inner horizons. Between the outer and inner horizons these black holes behave the same as regular old Schwarzschild (non-charged and non-rotating) black holes and everything falls towards the singularity until you cross the inner horizon and things go back to normal (in a sense) and you can avoid the singularity and eventually will exit another copy of the horizons (because gravity becomes repulsive inside the inner horizon) into "a different universe". In this "new universe" there will be another black hole and you can enter it, do the same thing over and over, effectively creating a tunnel of black holes.

These results come from solutions where the only thing in the entire universe is the black hole. The bad news is these tunnels are unstable and any little perturbation will cause the tunnel to close off by a process known as mass inflation. Essentially when you perturb a black hole it will radiate away deformations in the form of gravitational waves and eventually settle back into it's normal state. Part of this will be absorbed by the black hole and becomes infinitely blueshifted as it enters and gravity inside the inner horizon becomes attractive again and there is no getting out. (Note that all of this takes place inside the outer horizon and so is causally disconnected from the rest of the universe so you wouldn't notice the mass change). This also means they would also likely never exist because the gravitational collapse would have to be perfectly spherical and non-rotating to avoid mass inflation as the black hole forms.

I'm not really theorizing more of just not surprised

Yeah, I see what you're saying. I'm a little surprised that the physicists themselves were surprised ... *double checks grammar*. yeah.

This is cool but I'm much more intrigued by the subatomic myself.