Spyman

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You are right, looking back at my analogy with the flexible rope, the Hubble parameter is not the speed of the car, it's the rate of the expansion. An expanding universe should have a decreasing Hubble parameter and the local expansion of space should always be slowing. But the rate of change of the Hubble parameter can tell us the rate of acceleration. As I view the Big Bang, it began with a very rapid inflation, after which expansion continued due to momentum but with a decreasing rate since it got slowed by gravity, and then later dark energy started to dominate and accelerating the expansion again. So as I interpret it, the rate of expansion has been decelerating. Hmm, somehow I got the impression the acceleration started recently... (Maybe because of misleading "now" in images, like the one I linked.) This image has "today" more appropriately: http://www.space.com/php/multimedia/imagedisplay/img_display.php?pic=070501_matter_universe_02.jpg∩=Measurements+of+the+recessional+velocity%2C+distance+and+age+of+stellar+explosions+called+supernovae+provided+the+first+direct+evidence+that+the+rate+at+which+the+universe+is+expanding+is+increasing.+Credit%3A+NASA. Wikipedia says: "Cosmologists estimate that the acceleration began roughly 9 billion years ago." I don't know if using Morgans calculator this way gives correct values but: (1 Mpc = 3261600 LY, c = 299792.458 km/s, Omega = 0.27 Lambda = 0.73) z=1100.00 -> age= 00.00 BY, Hubble Radius= 00.725 MLY z=__55.00 -> age= 00.04 BY, Hubble Radius= 63.245 MLY -> Receding speed of Hubble Sphere 1.56c z=__20.00 -> age= 00.18 BY, Hubble Radius= 00.275 BLY -> Receding speed of Hubble Sphere 1.51c z=__10.00 -> age= 00.48 BY, Hubble Radius= 00.726 BLY -> Receding speed of Hubble Sphere 1.50c z=___5.00 -> age= 01.19 BY, Hubble Radius= 01.792 BLY -> Receding speed of Hubble Sphere 1.50c z=___2.00 -> age= 03.34 BY, Hubble Radius= 04.863 BLY -> Receding speed of Hubble Sphere 1.43c z=___1.00 -> age= 05.93 BY, Hubble Radius= 08.101 BLY -> Receding speed of Hubble Sphere 1.25c z=___0.90 -> age= 06.36 BY, Hubble Radius= 08.571 BLY -> Receding speed of Hubble Sphere 1.09c z=___0.80 -> age= 06.83 BY, Hubble Radius= 09.072 BLY -> Receding speed of Hubble Sphere 1.07c z=___0.70 -> age= 07.37 BY, Hubble Radius= 09.604 BLY -> Receding speed of Hubble Sphere 1.05c z=___0.68 -> age= 07.48 BY, Hubble Radius= 09.714 BLY -> Receding speed of Hubble Sphere 1.00c z=___0.66 -> age= 07.60 BY, Hubble Radius= 09.825 BLY -> Receding speed of Hubble Sphere 0.93c z=___0.60 -> age= 07.97 BY, Hubble Radius= 10.164 BLY -> Receding speed of Hubble Sphere 0.92c z=___0.50 -> age= 08.64 BY, Hubble Radius= 10.751 BLY -> Receding speed of Hubble Sphere 0.88c z=___0.40 -> age= 09.41 BY, Hubble Radius= 11.357 BLY -> Receding speed of Hubble Sphere 0.79c z=___0.30 -> age= 10.27 BY, Hubble Radius= 11.973 BLY -> Receding speed of Hubble Sphere 0.72c z=___0.20 -> age= 11.25 BY, Hubble Radius= 12.591 BLY -> Receding speed of Hubble Sphere 0.63c z=___0.10 -> age= 12.38 BY, Hubble Radius= 13.196 BLY -> Receding speed of Hubble Sphere 0.54c z=___0.00 -> age= 13.66 BY, Hubble Radius= 13.772 BLY -> Receding speed of Hubble Sphere 0.45c According to Morgans calculator the acceleration begun ~6 Billion Years ago. So, I was wrong, the acceleration did NOT start recently, as I thought.

Yes, thats right, most standard fuses has a positive temperature coefficient. But what I have been arguing is that the main point of a fuse is to have as low resistance as possible until it blows, due to limit losses. A device acting to limit the current by increasing resistance is NOT what I would call a normal fuse or circuit breaker. This is normal electrical fuses: http://en.wikipedia.org/wiki/Fuse_%28electrical%29 This is normal circuit breakers: http://en.wikipedia.org/wiki/Circuit_breaker Lets make an example: A 110 VAC supply with a 10 Amp slow-blow fuse of 0.01 Ohms, (cold), drained by a 11 Ohms power resistor. When the power is switched on the fuse is cold: - Current in the circuit is:110/(11+0.01)=9.99 Amps. - Voltage drop over the fuse is: 9.99*0.01=0.0999 Volts. - Energy generated as heat by the fuse is: 9.99*0.0999=0.998 Watts After a short while the temperature inside the fuse is raised and causes an increase in electrical resistance. How much? Well if it's going to limit a dead-short to 10 Amps in needs to be 11 Ohms, but lets say it only doubles to 0.02 Ohms. (You can try any increase of resistance but the outcome will be the same.) With increased resistance when the fuse is hot: - Current in the circuit is: 110/(11+0.02)=9.98 Amps. - Voltage drop over the fuse is: 9.98*0.02=0.1996 Volts. - Energy generated as heat by the fuse is: 9.98*0.1996=1.99 Watts As you can see the fuse gets hotter with increasing resistance, which will cause it to blow even faster. When the fuse is no longer able to dissipate the excess heat, the internal temperature will raise fast, causing it to melt and cut the circuit long before its increase in resistance is able to significantly limit the current. I hope I made my point clear this time - the resistance in a normal fuse is insignificant.

Well, if the Hubble parameter have been "getting smaller all the time", what does that tell you about the rate of expansion? It's only recently the acceleration has started. http://en.wikipedia.org/wiki/Image:Universes.GIF The Hubble constant is NOT constant, and the acceleration is not either. Wrong - The Hubble radius is where the recession velocity = c due to expansion. (The Hubble radius is neither the particle horizon or the event horizon.) [MATH]{D}_{H}= \frac{c}{H(t)}[/MATH] With H=71 km/s/Mpc -> D= ~13.7 BLY The most distant object we can see now is the CMB with z~1100 which is thought to be ~45 BLY distant from us now, but what we actually see today is a ~14 BY old signal from an old distance of ~0.04 BLY. If the expansion continues to accelerate we are not ever going to see what happened to the particles emitting the CMB, at the distance now ~45 BLY.

None of the two timelines presented states that the Sun will become a Black Hole or that planets will not be engulfed when the Sun enters a Red Giant stage. But yes, The Sun will not likely become a Black Hole and depending on different models Earth and/or Mars can become engulfed.

My advise to you would be to either present and explain your "theory" or ask more specific questions. Randomly saying things like: - The Black Hole at The Center of The Universe - Hubble only noticed 1/4 of what the Universe is doing - these letters make a pattern, (S/) (T\) (E/) (P\) - the center of the Universe is somewhere past the Corona Borealis - with the discovery of a Universal Axis - There is other evidence the Cosmos is Whirlpool Shaped - a finite Universe that definitely does have a center - but there is no such thing - I'm sorry - as Dark Energy - I estimate we have to fall into about seven Black Holes Without any evidence, is NOT going to get you anywhere, except maybe the thread moved to Pseudoscience. So do yourself a favour and explain your idea, but be prepared to prove it or to accept that you are wrong. (And take the opportunity to learn from the experience.)

Yes, at least thats how I interpret it, non-expert and all that... The expansion have been decelerating for a long time and that's way we can observe things like the CMB, (z~1100), which was receding with ~57 x c when the light was emitted and is now receding with ~3 x c. This thread deals with the expansion in general and I think it's a good read: http://www.scienceforums.net/forum/showthread.php?t=26714 I will cut down and post a quote of Martin, from the thread: Playing around with the z number, (redshift of emitted light due to expansion), in Morgans calculator, shows that the farthest we actually can see today, is objects with z=2 which where ~5.7 BLY distant when they emitted the light that reaches us now. Everything else was closer when the light was emitted, (but with lower z closer in time). [EDIT] Well, not actually the farthest we can see today, it's the farthest point which the light was emitted from.

Please don't choke on your foot now, losfomot. How about this analogy: Lets say you have a rope, (space), which is able to strech infinite. You tie one end to your house, (the Earth), and the other to the rear bumper of your car, (CMB), so the rope is straight and 10 m. Stick a map pin, (a distant star), through the rope in the middle between your house and car. A friend of yours takes off with your car with the speed of 10 m/s and the rope begins to stretch. The point where the rope is streching, (moving away from the house), with 5 m/s is where the map pin is. So you see, as the rope gets streched the distance to the pin increases. The point where the rope streches with a choosen constant speed is moving away from your house and as long as the car continues with constant speed, the point is disappearing with the same constant speed too. The confusion seems to arise when the car changes speed. Even if your friend would double the speed, the point continues to move away from your house, but during the cars acceleration we need to move the pin backwards to a quarter to keep a constant speed of 5 m/s. The speed of a point which are moving away with constant speed is also dependent of the acceleration of the car. The rate of the acceleration determines how fast we have to move the pin towards the house relative it's position on the rope. (Or towards the car during decceleration.) If the car is able to continue to accelerate with a highly enough rate, then the rate of the acceleration can force the point closer to the house. Now to answer your question, it depends on how the Universe will continue to behave... Some of the extreme models predicts a Big Rip where everything will be torn apart to particles which will leave each others horizons due to expansion. So you might spare the effort and just wait here on Earth. In the other extreme end, models predicts a Big Crunch where everything will end up in a universal sized Black Hole. In those cases your spaceship will not be able to leave Earth behind. I think most astrophysical data to date is consistent with a nearly flat universe that will not collapse and continue to accelerate. And if the Universe continues to expand with increasing rate, your spaceship will eventually reach your goal. But you will find yourself very very lonely out there in a dark Universe and not be able to return. (And very very old too. ) http://www.space.com/scienceastronomy/070501_scietues_futureuniverse.html

You missed my point. It's that simple...

No, the motor acts like a dead-short and causes a surge current, the fuse becomes highly resistive after it blowed.

I can see this pattern: S/T\E/P\ = Space Theory Explained Poorly.

There are losses involved in regulating a 9V battery's output down to 5V and if not regulating it down a motor made for 5V will use a lot more juice. I think this site might be helpful in choosing batteries: http://www.solarbotics.net/library/pieces/parts_elect_pass_batcomp.html If for example a Alkaline AA battery has a capacity of ~2800mAh and you want to run the motor for 4 hours then the motor can't use more than 2800mAh/4h=700 mA while running. If the motor is bigger/uses more than 5V*700mA=3.5Watt, you need more batteries in parallel. Have you tried running the motor on 4.5V ? Lowering the voltage also lowers the current and gives longer duration, but less power. For example with 6 AA Alkaline 2 parallels of 3 in series you have 3*1.5V=4.5V & 2*2800mA=5600mA. Which gives: 5600mAh/4h=1400mA and 4.5V*1400mA=6.3Watt.

AFAIK Fuses are generally not thought to change resistance or act like "current shunts".

http://en.wikipedia.org/wiki/Tesseract Animation -> http://en.wikipedia.org/wiki/Image:8-cell-simple.gif

http://en.wikipedia.org/wiki/Chronology_protection_conjecture I don't think Hawking meant that Nature would make deliberate decisions to prevent us from making a paradox... IMO He suspects and argues for a natural law of physics preventing the appearance of closed timelike curves. (More or less what Sayonara³ said.)

OK, I'll clearify, I don't think it's possible to travel to/from or communicate with our past, future or alternative timelines/universes.

Well, what do you think the other 3/4 of the Universe is doing ?

All devices on the same fuse shares the flow, but if everything is normal and functioning they should not limit each others flow. The only limit should be the fuse, which blows when overloading. The juice doesn't show up instantly, electricity has a speed too. If you turn on the light, it seems instant, but if you later on plug in a big consumer, like a powerful vacuum cleaner, which for a short moment during startup draws much, it will cause the voltage to drop temporarily, so the lights dims, but only for a short moment. If the lights gets more and more dim as you load the socket with more and more devices, I would advice to call an electrican, because something is seriously wrong. Your chargers is only a drop in the ocean for the HUGE generators supplying the power. (If not a small private portable generator.) Lets take my home and neighborhood as an example. The city has large wires providing power for the city and our industries, several transformation stations shares that power and distributes it out to smaller transformators, from where it goes to small distributions cabinets and eventually to my house. The cable to my home is fused with 63 Amps in the cabinet at the street corner, and it has plenty of such fuses for the other dozens houses in that area. The cabinet is able to distribute enough power for those houses to keep warm during winter, and it is backed up with more than that power. Inside my house the main fuses are of 16 Amps and then comes the smaller fuses, (10 Amps & 6 Amps), for different rooms, (light & sockets), and other devices like house heater, stove and refrigerator. Theoretically, I have the full power from the main generator, (except losses), available in any socket in my house. The purpose of the fuse is to protect the cables from melting. There are exceptions as always, (a few listed below): - In some areas, typically farms far out in the country, the length of the cable itself can strangle the avaliable power so the fuse won't blow and the lights stays dimmed for the duration of a heavy load. - Or like in my area, we have a heavy steel industry which can load the whole supply to our town, so much that the lights can dim for several minutes in my house. - Also in an industry it is sometimes useful to limit the current by other means than a fuse, which in such case also would cause the lights to stay dim when applying a heavy load. Thats way I asked if your sockets are supplied normally or specially. Hmm, I don't know if I managed to explain that good enough... There is normally nothing strangling the available power to your wall sockets ! (Except losses in the wires, which are brought down to minimum.) The only thing limiting the power is: * the generator, probably very powerful, * the fuse, which only will blow or not, nothing else, * the connections, to weak results in Fire or malfunction, * the wires, to weak results in Fire or malfunction, * the socket, to weak results in Fire or malfunction, (* very long wires can cause a voltage limit, not current.) The fuses are there because if you load the wire with to much power it will melt the insulation, glow like the wire in a light bulb and start a fire. The fuses should be dimensioned to protect the weakest point in the circuit. But if nothing is wrong, then you have the current the fuse is marked with, at any one socket it is supplying until the fuse blow and the voltage should only drop very temporarily when a heavy load is connected and then return to normal. If you have a load that needs 2 Amps connected in a socket, it drains 2 Amps through the fuse. When you connect a second load of 4 Amps, it drains 4 Amps through the fuse, the first load still drains 2 Amps and the fuse now have a current of 2+4=6 Amps flowing through it. If the fuse is marked 6 Amps, you are very close to the blow limit, it might blow after several hours or last days, depending of manufacturing quality. Adding a third load of 1 Amps will cause the fuse to get hot and blow after some time depending of the speed of the fuse, normally it is "slow", (marked with a snail), which allows some small overloads for a short duration of time, (like when a vacuum cleaner starts). But until the fuse blows you will have 2+4+1=7 Amps without restrictions, (except for some very small losses). If nothing is wrong, (or special), then the voltage stays normal during all the connections, (except for small dips). The generators supplying the power to your company is probably supplying power to a large part of your town, unless your company is so big it needs it's own generator, in which case it's still supplying more than your small working area, (building), so it's not likely it will be noticeable affected if you connect one, ten or hundreds of small battery chargers. It is capable of supplying the rated voltage and enough current to blow your tiny fuse without noticing. Hopefully that is clear enough... If you don't trust me, you can always test it, yourself... - Drain a set of batteries to a certain known level. - Measure the charging time for one charger only connected. - Drain several sets of batteries to the same level. - Measure the charging time with several chargers connected. If I am right the time would be the same, except for small differences in the batteries/chargers. If you are correct 5 chargers will take 5 times longer to charge the batteries, (or at least much longer). Another way could be to measure the voltage/current at/through the socket with one and several chargers connected. If I am correct the voltage won't change and the current will rise to what the chargers use together. Please note that the power in the socket is harmful and deadly ! (Don't mess with it, if you don't know what you are doing.)

The matter is ejected from the accretion disc, not from inside the BH. All that is know is that the BH gains the mass of what it consumes. Black Holes don't have any theoretical maximum size or mass that limits them. When galaxies collide, the supermassive Black Holes anchoring them in the center, might merge and create a new bigger BH. Black Holes are thought to rotate, if the star that ends up as a BH is spinning and conservation laws says that angular momentum is preserved, then the BH needs to be spinning to. From concepts drawn of rotating black holes, it is shown that a singularity, spinning rapidly, can become a ring-shaped object. This results in two event horizons, as well as an ergosphere, which draw closer together as the spin of the singularity increases. When the outer and inner event horizons merge, they shrink toward the rotating singularity and eventually expose it to the rest of the universe. http://en.wikipedia.org/wiki/Naked_singularity

Leaving a Black Hole is thought to be impossible. I think all time there is would have passed - thats infinite time or eternity. Hawking radiation is newborn particles, created outside the Event Horizon.

The distance between the singularity and where you want to measure the gravity field. A Black Hole Singularity is a body with zero radius so you can measure the field from zero distance without crossing a surface of the body.(It's a point without height, length or width) In nature when a star of 3 or more times mass of the Sun goes supernova and at least 1.44 times solar masses is not ejected a gravitational collapse to a Black Hole can happen. The collapse forces all the mass of the star to the singularity. Gravity depends only on the mass and the energy in the body. The curvature of spacetime is the same, but since the density is higher the body will be smaller. If you where able to squeeze the Earth down to a radius of 9 millimeters it would become a Black Hole. An astronaut in the Space Station or on the Moon wouldn't notice any difference of the gravitational field around him. (But he would have a hard time trying to spot Earth, a small black pebble.) The difference is that you are able to get closer to the center of a more dence object and still be outside of the body and under the influence of it's full gravity. Earth radius is 6 378.137 km so we are that distance from the center and weights 9.81 times our mass, but if it where a Black Hole we would be 9 millimeters from the center, if standing on the Event Horizon, where we would weight around 5 000 000 000 000 000 000 times our mass. In principle yes, but the difference wouldn't be years, it's more like below one millisecond per day for the Sun, below 100 microseconds for Earth, around a few nanosecond for the Moon/Pluto. (All compared to a void inside the Milky Way.) Note that we are still in the Suns gravitational field here on Earth or on Pluto and the Suns influence on time dilation, is bigger than Earths, even on Earth. If you where able to move outside of Milky Way to a big empty void deep in space, time would pass by around 0.5 seconds per day faster than on Earth inside. The Moon are moving in a geodesic line around Earth, it is falling towards Earth in freefall but due to orbital speed always fail to hit Earth. Inside the Event Horizon of a Black Hole, spacetime curvature is so high that if not moving faster than c, (lightspeed), the curvature will bring you closer to the center, since nothing can move faster than c, everything is forced to end up there. If everything ends up in the center, you get a body with zero radius and if standing on the singularity, you would weight infinite times your weight on Earth.

Nobody is critisizing or calling your questions stupid... They are only trying to explain that if the rules for a theory is broken, then the theory can't predict any results for the event causing the break down. According to relativity all sorts of weird things could happen, but since the predictions of the theory are wrong, the theory no longer apply. Anyone can tell you what they guess would happen, but you can't demand a theory to supply an answer for a situation the theory itself claims to be impossible.

But you are forgetting that the particle must carry the huge weight from everything above, on it's back, and with nothing to stand on it will be pushed down to the center. The temperature and pressure deep inside Earth is IMMENSE, no hollow can sustain itself there. If you imagine a planet made only of liquid water, could the center be hollow ? Sure, there can be small hollows, bubbles, but buoyancy would push them towards the surface. (You can test this by blowing bubbles in a glass of water.) Now, add some gravel to the water, would gravity pull the gravel to the center ? (You can test this by dropping small pebbles in a glass of water.)

No, "environmental unfriendliness" would not be the reason it was sent away from the earth. I doubt the reason for sending it to Saturn was because it was so big or inefficient also... RTGs are usually the most desirable power source for unmanned or unmaintained situations needing a few hundred watts or less of power for durations too long for fuel cells, batteries and generators to provide economically, and in places where solar cells are not viable. http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator

1. Space is normally defined to consist of three spatial dimensions, (width, height and length), if any or all of them is bent in another dimension then space is not flat. The sheet of paper is representing two of the known spatial dimensions and the third dimension is used to show the bending in another dimension. Link to read: http://en.wikipedia.org/wiki/Shape_of_the_Universe 2. According to Relativity, the force of gravity is caused by the geometry of spacetime. Link to read: http://en.wikipedia.org/wiki/General_relativity One problem is that at the Singularity, (the center of a Black Hole), the curvature becomes infinite because the density is infinite. The volume of a sphere with any mass and zero radius has infinite density and since the strength of gravity also depends on distance it's infinite too when the distance is zero. It's thought to be unphysical and a flaw in Relativity that future revisions will sort out. Link to read: http://en.wikipedia.org/wiki/Gravitational_singularity'>http://en.wikipedia.org/wiki/Gravitational_singularity ALL matter and energy is deviated from it's course when passing by ALL matter or energy. Take Earth, where do you think the Moon would go if Earth didn't affect it's course? There is no difference with Black Holes, they are only more massive and dense. Link to read: http://en.wikipedia.org/wiki/Gravitation Time ticks slower on Earth than on the Moon, closer to a more massive object causes time to tick slower. No difference with Black Holes here either. Link to read: http://en.wikipedia.org/wiki/Time_dilation