Balck Holes too soft
 

I am having discussions with my other players in the games that we are playing and it is about the fact that Black hloes only draw in at 2.
I would like to see them do it at 6, thus making life very difficult for tech 1 type engines.

Any thought??

Re: Balck Holes too soft
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Aussie Gamer:
I am having discussions with my other players in the games that we are playing and it is about the fact that Black hloes only draw in at 2.
I would like to see them do it at 6, thus making life very difficult for tech 1 type engines.

Any thought??<HR></BLOCKQUOTE>

actually, they should draw in more, the closer you are. This would probably require a code change.

Re: Balck Holes too soft
 

The AI can not even barely handle 2,
But just for you, I have increased them to 6.
Load this file into the data file, overwrite the SystemTypes

The only thing I changed is the number of sectors a blackhole pulls a ship to the cneter per turn.
Enjoy

And remember, AI's will not be able to handle this. I think if you human control them for one turn, You can set up were they void blackhole systems. (this I have not tryed)

Re: Balck Holes too soft
 

Actually, they should not pull ships in at all!

Since even supergiant stars don't pull ships in, a black hole should not pull ships in.

If the earth was crushed into a black hole for some mysterious reason, all the satellites we have in orbit would stay in orbit for centuries.

Once you're in orbit, you stay in orbit. Since ships have stable positions in normal systems, they are clearly orbiting the star at the same rate as the planets.
If the ships do this in a black hole system, then they will not fall in, even if they have no engines.

Re: Balck Holes too soft
 

I have pulled my statment until I recieve a response from Mr. hawkings

[This message has been edited by Dracus (edited 30 March 2001).]

Re: Balck Holes too soft
 

Dracus bloviates:
If you don't have a planet (IE earth crushed) then the sats would be pulled in, because
then there would be no orbit. orbits are based on speed ver grav. That is why we have
to push our sats back up, because in time, grav overpowers them. All the planets are
slowly being pulled toward the sun. It will take billions of years but in time the earth
will crash into our sun. Take a science math course or read a steven Hawken book. It
is all explained there.

Lord Felix, a member of the American Academy for the Advancement of Science, responds:
Nope, that's all nonsense. Satellites would orbit an earth-mass blackhole EXACTLY the way they would orbit the Earth. In an idealized system including NOTHING but the Earth and the Moon in orbit, the orbit would remain unchanged forever. In reality, due to the slow attraction of the rest of the universe, the Moon is actually RECEDING from the Earth and it will NEVER fall in as you say! In the dinosaur age, the Moon was visibly larger in the sky, not smaller. Small human satellites slowly fall, and must be boosted up to maintain orbital altitude, due to the slowing effect of friction (they bump into millions of air molecules). Your post is remarkable for being incorrect in every single detail, including the spelling of Hawking's name! It's a bad idea to be arrogantly dismissive when all your facts are wrong!

Re: Balck Holes too soft
 

I was about to respond before you did, Felix, when an interesting thought occurred to me. gravitational attraction is often modeled as a point source at the center of gravity of the bodies, when in reality, the attraction is conic with the radius of the attracting bodies being the radius of the 2 ends of the conic section and gravitational attraction being strongest along the axis of the cone and falling off as you reach the edges. In the case of the earth becoming a black hole, one end of the cone will collapse from having the radius of the earth to having a radius of approximately 1/2 centimeter. The black hole scenario will more closely resemble the simple mathematical model, but will there be any effect on the orbit given the new configuration of the attraction? Is the point source gravitational model accurate, or just close enough for us laymen?

Re: Balck Holes too soft
 

Orbits around a spherical body can be calculated exactly by the point source method. Since the Earth is not perfectly spherical, there are some minor perturbations that cause the orbit to wobble a bit. The basic size and shape of the orbit do not change, it just wobbles like a top.
If the Earth was replaced by a black hole of the same mass, everything in orbit would stay in orbit. The gravitational forces caused by one earth mass at a fixed distance from the center of mass will not change just because it is converted to a black hole. It will actually probably Last longer because the air resitance would be removed.
Of course, whatever caused to Earth to become a black hole may have some slight impact on the orbiting satellites.
Steve

Re: Balck Holes too soft
 

And so, it looks like you all agree with my point about how black holes should not pull ships in.

A better model for the black hole would be a scaled damage from the center out.
Flying past the event horizon is very bad. Orbiting really close would shear your ship apart (since the closer bits of ship orbit faster that the farther out ones and/or gravitational shear since the gravity pulls harder on the closest part of the ship)
farther out, say halfway to the edge of the system, heavy, normal damage would be incurred by the accretion disk we see.

ie.
Center square: instant loss of the ship
ring 1: take (5 x mass of ship) damage
ring 2: take (1 x mass of ship) damage
rings 1-5: take 750 damage

Re: Balck Holes too soft
 

I may have spelled his name wrong sir, but I am well read on his books.
The facts and fiction of Star trek:
Black Holes and baby Universes:

And have watched a number of his tv specials.

I never said the moon would fall. You can not compare the moon to man made sat.

Yet we all may be wrong to some degree or may have miss-understood some of his statments.
therefore,
I have taken to e-mailing him with this issue and will post his reply if or when I get one.

At which time, I will gladly state if I am in error.


Thank You and good Day.

Subject: Message to Professor Hawking e-mail account


Your mail has been received and will be read and dealt with
appropriately over the next few days.

Professor Hawking very much regrets that due to the severe limitations
he works under, and the huge amount of mail he receives, he may not
have time to write you a reply.

Yours faithfully


Neel Shearer

Graduate Assistant to
Professor S W Hawking CH CBE FRS
Lucasian Professor of Mathematics


Department of Applied Mathematics and Theoretical Physics,
University of Cambridge,
Cambridge, CB3 0WA.
United Kingdom.


P.s----
for those of you who do not want blackholes to pull your ship in. I have made a file for that. You will still recieve damage if you pass across the center. smaller ships maybe distroyed by this, but the larger ships will not.

Some facts for your enjoyment:

Usually, mass is determined by the
orbital periods of the planets' satellites. Newtonian gravity combined with Kepler's third law
of motion gives: T2 = 4 pi2a3/(GM) (where T = satellite orbital period, a = satellite semimajor
axis, G is the gravitational constant, and M is the planet's mass). For Mercury and Venus,
spacecraft deflections past the planets have given precise masses.

The moon is in synchronous rotation, so that it always shows the same face to the surface of
the Earth.

he Earth is slowing down and the
Moon is getting further away. In the past, the ``day'' and ``month'' were both much shorter.
Eventually, the Earth will always keep one face towards the Moon (Like Pluto and Charon).

Most people cite the fact that in about 5-6 billion years the Sun will become a red giant star, and swell to the orbit of Venus or even the Earth in size.
Actually, even now, the Sun grows brighter and brighter as its is evolving 'off' the main sequence. In another 500 million years of this steady
increase, it will be about 10 percent more luminous. This means that the surface of the Earth will be a LOT hotter as the oceans begin to dump more
water vapor into the atmosphere and thereby increasing the terrestrial greenhouse effect. Some forecasts suggest that in as little as another few
hundred million years, the Earth's biosphere may turn very inhospitable. Fortunately, there are 'thermophylic' bacteria that live in nearly boiling
water, so again in the far future, the Earth will end its years as a host for life by being a breeding ground for bacteria. We had better not be here
when that happens.


When two large objects orbit each other, matter may be transferred from the less dense to the denser object. The more
massive, compact object "accretes" matter from its neighbor due to its greater gravitational pull. Mass transfer may result
in gravitational radiation.


From Steven Hawkings web site:

Pile enough matter into a small enough volume
and its gravitational pull will grow so strong that
nothing can escape from it. That includes light,
which travels at the absolute cosmic speed limit
of 186,000 miles per second. In a stroke of
descriptive genius, physicist John Wheeler
named these objects “black holes.” The radius
of a black hole is called the event horizon
because it marks the edge beyond which light
cannot escape, so any event taking place inside
the event horizon can never be glimpsed from
outside—in effect, the inside of the black hole is
cut off from our universe. It has even been
speculated that black holes could be pathways
into other universes. Gravity is so strong at the
center of a black hole, that even Einstein’s
gravitational laws must break down. The theory
that governs the incredibly dense matter and
strong gravitational fields at the center of a black
hole is not yet known.”
Black holes are usually thought of as
objects with such strong gravity that
nothing, not even light, can escape from
them. However, Stephen Hawking has
shown that black holes can radiate energy.
The reason goes back to quantum
mechanics and the uncertainty principle. For
very brief periods of time, matter or energy
can be created from “empty” space
because no such thing as truly empty space
exists. Hawking realized that if a
particle/anti-particle pair came into
existence near the event horizon of a black
hole, one might fall into the hole before
annihilating its anti-particle. The other
particle could then escape the gravitational
clutches of the black hole, appearing to an
outside observer as radiation.


This space-time was not flat, but was warped and curved by the matter and
energy in it. In order to understand this, considered a sheet of rubber, with a weight placed on it, to
represent a star. The weight will form a depression
in the rubber, and will cause the sheet near the star
to be curved, rather than flat. If one now rolls
marbles on the rubber sheet, their paths will be
curved, rather than being straight lines. In 1919, a
British expedition to West Africa, looked at light from
distant stars, that passed near the Sun during an
eclipse. They found that the images of the stars
were shifted slightly from their normal positions. This indicated that the paths of the light from the
stars had been bent by the curved space-time near the Sun. General Relativity was confirmed.

Consider now placing heavier and heavier, and more
and more concentrated weights on the rubber
sheet. They will depress the sheet more and more.
Eventually, at a critical weight and size, they will
make a bottomless hole in the sheet, which particles
can fall into, but nothing can get out of.

What happens in space-time according to General
Relativity is rather similar. A star will curve and
distort the space-time near it, more and more, the
more massive and more compact the star is. If a massive star, which has burnt up its nuclear fuel,
cools and shrinks below a critical size, it will quite literally make a bottomless hole in space-time, that
light can't get out of. Such objects were given the name Black Holes, by the American physicist John
Wheeler, who was one of the first to recognise their importance, and the problems they pose. The
name caught on quickly. To Americans, it suggested something dark and mysterious, while to the
British, there was the added resonance of the Black Hole of Calcutta. But the French, being French,
saw a more risqué meaning. For years, they resisted the name, trou noir, claiming it was obscene.
But that was a bit like trying to stand against le weekend, and other franglais. In the end, they had
to give in. Who can resist a name that is such a winner?

We now have observations that point to black holes in a
number of objects, from binary star systems, to the centre of
galaxies. So it is now generally accepted that black holes
exist. But, apart from their potential for science fiction, what
is their significance for determinism. The answer lies in a
bumper sticker that I used to have on the door of my office:
Black Holes are Out of Sight. Not only do the particles and
unlucky astronauts that fall into a black hole, never come out
again, but also the information that they carry, is lost
forever, at least from our region of the universe. You can
throw television sets, diamond rings, or even your worst
enemies into a black hole, and all the black hole will
remember, is the total mass, and the state of rotation. John Wheeler called this, 'A Black Hole Has No
Hair.' To the French, this just confirmed their suspicions.

As long as it was thought that black holes would continue to exist forever, this loss of information
didn't seem to matter too much. One could say that the information still existed inside the black hole.
It is just that one can't tell what it is, from the
outside. However, the situation changed, when I
discovered that black holes aren't completely black.
Quantum mechanics causes them to send out particles
and radiation at a steady rate. This result came as a
total surprise to me, and everyone else. But with
hindsight, it should have been obvious. What we think
of as empty space is not really empty, but it is filled
with pairs of particles and anti particles. These appear
together at some point of space and time, move apart,
and then come together and annihilate each other.
These particles and anti particles occur because a
field, such as the fields that carry light and gravity, can't be exactly zero. That would mean that the
value of the field, would have both an exact position (at zero), and an exact speed or rate of change
(also zero). This would be against the Uncertainty Principle, just as a particle can't have both an
exact position, and an exact speed. So all fields must have what are called, vacuum fluctuations.
Because of the quantum behaviour of nature, one can interpret these vacuum fluctuations, in terms
of particles and anti particles, as I have described.

These pairs of particles occur for all varieties of elementary particles. They are called virtual
particles, because they occur even in the vacuum, and they can't be directly measured by particle
detectors. However, the indirect effects of virtual particles, or vacuum fluctuations, have been
observed in a number of experiments, and their existence confirmed.

If there is a black hole around, one member of a particle
anti particle pair may fall into the hole, leaving the other
member without a partner, with which to annihilate. The
forsaken particle may fall into the hole as well, but it
may also escape to a large distance from the hole,
where it will become a real particle, that can be
measured by a particle detector. To someone a long
way from the black hole, it will appear to have been
emitted by the hole.



[This message has been edited by Dracus (edited 30 March 2001).]

Re: Balck Holes too soft
 

Hahahahaha!

Thats a perfect example of an OJ defence http://www.shrapnelgames.com/ubb/ima...ons/tongue.gif

Flood them with BS till they go away!
(much of that is true, but has no bearing on the discussion)

You appear to have said that you now agree that the moon would not fall in if the earth was squeezed into a black hole (which would have an EH roughly the size of a marble, FYI)
I hope then that you would realize that anything in orbit will stay in orbit nearly forever.
Therefore ships that sensibly go into orbit around normal stars, should (with a sane captain) go into orbit around the black hole, and hence not get sucked in

Note that for our purposes, hawking radiation is minimal, since we are talking about a solar mass or higher.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>I never said the moon would fall. You can not compare the moon to man made sat.
Yet we all may be wrong to some degree or may have miss-understood some of his statments.<HR></BLOCKQUOTE>

The moon is easily compared to a man-mad sattelite. They both orbit the earth. The only difference is that the sat is smaller, and gets bumped around by gasses & solar wind. they still follow the same rules, and crushing the earth into a black hole would not suck any orbiting body in.

If the "him" you are referring to is S. Hawking, nothing about orbiting a black hole has anything to do with him. It is simple orbital mechanics.

[This message has been edited by suicide_junkie (edited 30 March 2001).]

Re: Balck Holes too soft
 

Do you or do you not want the files that change the way black holes work in the game?
If not then I will remove them.

Re: Balck Holes too soft
 

A little OT but did't someone make a mod or give instructions to prevent BH from being generated in the game. I don't like them. Anyone know what the mod was called or have easy instructions on how to do it?

Re: Balck Holes too soft
 

nice quotes &lt;grin&gt;

There is a game explanation for the 2 moves per turn towards the center in a black hole system. The wormholes in a normal system tend to be many AU from the central stars (i.e. at the edge of the screen) and the scale of the solar system display is many AU across.
To make things work assume that wormholes are attracted to gravity gradients, so they are much closer to black holes than normal, equally massive stars. The screen scale of a black hole system would then be much less, say .1 AU across. Since you are much closer to the central mass than you would normally be, the gravitational pull would be greater. Also assume that the "space drive" engines don't have the same top velocity near a singularity, so the ships still only move 1 square per "move".
While not a pretty solution, it can explain the extra motion towards the center. The center square represents the space immediately around the event horizon which causes damage through gravitational shear and/or intense radiation from the accretion disk.

Steve

Re: Balck Holes too soft
 

Nitram: I hate the Black Holes, because they are a great problem for the AI players, then, I have removed them from my games.

To do it, you only need to go into the file QuadrantTypes.txt (under the Data folder), and search the words 'Black Hole'. Then every time that you find the word (will be several times, because is for every type of quadrant), replace the Chance for 0.
If you have the Modpack installed, you need to do it into the folder Data, but under the Modpack folder.

Re: Balck Holes too soft
 

Personally, I don't need them. I've got stuff modded, so I can't use them as is.
Adjusting the black hole's ability is not exactly a full day's work, either

I'm sure that there are many who would be interested though.

My objections so far:

1) Oggy ben Doggy's statement (post #2) is only correct if the ships are not orbiting, and since they orbit normal stars (ie. don't fall in) then the captain should just be orbiting the hole.

2) Dracus (a second-hand quote, since the original post was blanked out)
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>If you don't have a planet (IE earth crushed) then the sats would be pulled in, because then there would be no orbit. orbits are based on speed ver grav. That is why we have to push our sats back up, because in time, grav overpowers them. All the planets are slowly being pulled toward the sun. It will take billions of years but in time the earth will crash into our sun. Take a science math course or read a steven [Hawking] book. It is all explained there.
<HR></BLOCKQUOTE>
Which is full of errors. You claimed that the satellites would fall in, yet you also say that the moon would not.
- Both are in orbit, both would stay in orbit
- also, the planets are not falling into the sun. In fact, the Moon is drifting away from the earth because of tidal forces.
eg: the moon pulls a bulge of water towards it (that's the tides) but the spinning earth pushes the bulge ahead of the moon. The gravitational tug from the bulge pulls the moon ahead a little bit faster, and the moon slowly accelerates, expanding its orbit, while the rotation of the earth slows (due to friction with the bulge).
The exact same thing happens with the Sun & Mercury.

------------------
Append:

Steve A: If wou make the black hole system 0.1 AU across, then the accretion disk would be huge, rather than just 1 square of damage.
Also, it dosen't explain why the ship captain fails to go into orbit like he does for stars.

[This message has been edited by suicide_junkie (edited 30 March 2001).]

Re: Balck Holes too soft
 

more info on black holes
Known Black Holes Number 30
Galaxies with a big bulge of stars in the middle are much more likely to spawn a massive black
hole, while comparatively flat-bellied galaxies like our Milky Way harbor black holes with only a
few million solar masses, the scientists said in statements.
Scientists at the University of Texas, the University of California at Santa Cruz and the
University of Michigan were able to reach these conclusions because of the recent discovery of
10 super massive black holes in galaxy centers, raising the total number of known black holes to
30, a large enough group for study.
To measure the masses of black holes — huge matter-sucking drains that gobble up
everything that gets within their pull, even light — astronomers used the average speed of stars
near the black hole.
The closer the stars get to the black hole, the faster they move. The galaxies with small to
average star speeds have small black holes, while those with very high speeds contain
extremely large black holes, the astronomers found.
Copyright 2000 Reuters.



[This message has been edited by Dracus (edited 30 March 2001).]

Re: Balck Holes too soft
 

Dracus,
There was an article in the Baltimore Sunpapers about 3 weeks ago. Scientists at Johns Hopkins now estimate the number of Black Holes to be ~2 million. The article quotes the scientists as saying " they are like cockroaches".

Re: Balck Holes too soft
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by raynor:
If I take an object with arbitrary mass and vector, it sounds to me like you are saying that when it approaches a stellar body of planetary mass or larger, there is a 100% guarantee that said object will enter into stable orbit around the stellar body?

Fascinating...<HR></BLOCKQUOTE>

Noooo. I'm saying that the Captain of said object would put his ship in orbit, assuming that he's not suicidal.

The other thing that I'm saying is that anything already in orbit will not fall out of orbit just because its orbiting a black hole.

Re: Balck Holes too soft
 

I have done some more research.

There is no limit in principle to how much or how little mass a black hole can have. Any amount of mass at all can in principle be made to form a black hole if you
compress it to a high enough density. We suspect that most of the black holes that are actually out there were produced in the deaths of massive stars, and so we expect
those black holes to weigh about as much as a massive star. A typical mass for such a stellar black hole would be about 10 times the mass of the Sun, or about 10^{31}
kilograms. (Here I'm using scientific notation: 10^{31} means a 1 with 31 zeroes after it, or 10,000,000,000,000,000,000,000,000,000,000.) Astronomers also suspect that
many galaxies harbor extremely massive black holes at their centers. These are thought to weigh about a million times as much as the Sun, or 10^{36} kilograms.

The more massive a black hole is, the more space it takes up. In fact, the Schwarzschild radius (which means the radius of the horizon) and the mass are directly
proportional to one another: if one black hole weighs ten times as much as another, its radius is ten times as large. A black hole with a mass equal to that of the Sun
would have a radius of 3 kilometers. So a typical 10-solar-mass black hole would have a radius of 30 kilometers, and a million-solar-mass black hole at the center of a
galaxy would have a radius of 3 million kilometers. Three million kilometers may sound like a lot, but it's actually not so big by astronomical standards. The Sun, for
example, has a radius of about 700,000 kilometers, and so that supermassive black hole has a radius only about four times bigger than the Sun.

A black hole has a "horizon," which means a region from which you can't escape. If you cross the horizon, you're doomed to eventually hit the singularity. But
as long as you stay outside of the horizon, you can avoid getting sucked in. In fact, to someone well outside of the horizon, the gravitational field surrounding a black hole
is no different from the field surrounding any other object of the same mass. In other words, a one-solar-mass black hole is no better than any other one-solar-mass
object (such as, for example, the Sun) at "sucking in" distant objects.

A black hole in a close orbit around a star can pull the top layers of the star off the surface and
down its own gravity well. Once the material passes beyond the black hole's event horizon, it is
gone, and more stuff can be consumed by the black hole. You are left with a slightly larger black
hole, and a slightly less massive star, so the black hole can pull a little more material off the star.
This continues until the star is gone, and the black hole's hunger is yet unabated.

Re: Balck Holes too soft
 

If you are interested in Black Holes and such there is up to date info at www.chandra.harvard.edu

[This message has been edited by Nitram Draw (edited 30 March 2001).]

Re: Balck Holes too soft
 

here is a cool drawing of a sun being lunch for a black hole.
came from that site.




[This message has been edited by Dracus (edited 30 March 2001).]

Re: Balck Holes too soft
 

if any is interested, I found an article on how a wormhole may in theory exist/work.

Re: Balck Holes too soft
 

Agggh!

Let me make it as simple as I can.

It dosen't matter whether you are talking about:
- your ship VS an asteroid
- your ship VS a planet
- your ship VS a star
- your ship VS a Black Hole

IN orbit ==&gt; stay in orbit ==&gt; no crash
Not IN orbit (eg. stationary) ==&gt; fall in ==&gt; die horrible death

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>In other words, a one-solar-mass black hole is no better than any other one-solar-mass object (such as, for example, the Sun) at "sucking in" distant objects.<HR></BLOCKQUOTE>
Yes! Exactly.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>A black hole in a close orbit around a star can pull the top layers of the star off the surface and down its own gravity well. Once the material passes beyond the black hole's event horizon, it is gone, and more stuff can be consumed by the black hole. You are left with a slightly larger black hole, and a slightly less massive star, so the black hole can pull a little more material off the star<HR></BLOCKQUOTE>
Now, one caution here:
The Hole isn't "sucking" the gas off of the star. The star's gas is slowly smeared out by the gravitational shear & drifts into the accretion disk, which radiates energy & sinks towards the hole.

The Hole & star are orbiting each other, but lets take the viewpoint of the hole.
Relative to us, we aren't moving.
The star is orbiting us, but it is really fat compared to the hole.
Now, imagine drawing an ellipse (circle) tracing out the star's path. Some of the star's gas is too far out & some is too far in. The farther out the orbit, the slower you move, so the outside (away from the hole) is moving too fast for it's orbital distance, while the inside is moving too slow.

The Gas that's moving too slow tends to drop inwards towards the hole, while the fast gas stretches outwards. The slow gas transfers from orbiting the star to the hole, where it joins the accretion disk.

The accretion disk radiates heat from the friction between different layers (inner ones orbit faster) and the gas loses energy & slowly falls in.

Re: Balck Holes too soft
 

All this stuff That I have posted comes from a number of research web sites, word for word.

Things would only orbit as long as they were outside the horizon. Different sites describe the Horizon a little different, but this may be due to the fact that no one has ever been near an actual black hole. Some say the horizon is were the grav pull increases, some say it is were light can no longer escape. either way, inside the horizon, you die. So there for I stand corrected. But we must all agree, that until we actual travel to a real black hole, we will truely never know. So everything you stated is based on the rules that man thinks it understands. But the universe has a way of surpising us now and then.

Here is a question for you--could our sun become a black hole?

I'm out




[This message has been edited by Dracus (edited 30 March 2001).]

Re: Balck Holes too soft
 

I don't know a whole bunch about black holes and other phenomenon but here is my question:

A black hole has a huge mass right? So if a ship tried to orbit it, would it take lots of energy to remain in orbit?

Just Curious.

BY THE WAY, have you stopped by the updated Spoogy Federation website?
http://spoogyfederation.tripod.com

Re: Balck Holes too soft
 

If a spacecraft the size of the shuttlecraft exited a hypothetical wormhole and found itself 100 KM from the outer corona of a star the size of our sun, what velocity would that spacecraft have to achieve in order to maintain a stable orbit around the star?

A multi-part question

1. A spacecraft the size of the shuttle approaches our sun on a course aimed directly for the 'center' of the star.
2. Take the main engines used to achieve escape velocity out of the equation.
3. Assume the spacecraft doesn't use any fuel until it reaches closest approach.
4. Assume that heat/radiation aren't a factor--robotic pilot if you want.

How close do you think the spacecraft can get to our sun before it must alter its course to try to enter an orbit around the star?

[This message has been edited by raynor (edited 30 March 2001).]

Re: Balck Holes too soft
 

Raynor,
Orbital velocity at the sun's surface is 436 km/s. Spacecraft size does not matter as long as it is significantly smaller than the sun in mass.

If a ship fell towards the sun's surface from very far away, it would be traveling roughtly at escape velocity straight towards the core when it hits the surface. That velocity is 616 km/s at the sun's surface. To get into a circular orbit at that point, you would have to reverse the 616 km/s to stop the fall and add 436 km/s sideways to enter orbit. You can do both at once (a**2 + b**2 = c**2) with a delta velocity of 755 km/s.

The game engines don't really use delta V so it's hard to answer your question. The various books and board games SE4 is loosely based on have engines that propel spacecraft at 1% to 5% of lightspeed (3000 km/s to 15000 km/s), so it should be no problem for them to hover over the surface of the sun.

Steve



[This message has been edited by Steve A (edited 31 March 2001).]

Re: Balck Holes too soft
 

capt_spoogy,
Black holes can come in many masses, from around 5 solar mass to millions of solar masses. The energy it takes to get into orbit around a 5 solar mass black hole is exactly the same as the energy it takes to get into orbit around a 5 solar mass star.

Steve

Re: Balck Holes too soft
 

Dracus,
No, our sun will eventually end up as a white dwarf unless somebody uses a stellar converter on it.

&lt;grin&gt;

Steve

Re: Balck Holes too soft
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Here is a question for you--could our sun become a black hole?<HR></BLOCKQUOTE>
Yes. Even Earth would become a black hole if you squeezed it down to the size of a marble (1 cm)
Will it happen naturally? Not a chance.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>A black hole has a huge mass right? So if a ship tried to orbit it, would it take lots of energy to remain in orbit?<HR></BLOCKQUOTE>

To remain in orbit takes zero energy. Just take a look at the sun/earth/moon.

It may take a lot of energy to get into orbit from the surface, but once you're there you're there for good until you hit something, or generate thrust.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>1. A spacecraft the size of the shuttle approaches our sun on a course aimed directly for the 'center' of the star.
2. Take the main engines used to achieve escape velocity out of the equation.
3. Assume the spacecraft doesn't use any fuel until it reaches closest approach.
4. Assume that heat/radiation aren't a factor--robotic pilot if you want.
How close do you think the spacecraft can get to our sun before it must alter its course to try to enter an orbit around the star?<HR></BLOCKQUOTE>

The key to getting an orbit is to have a mass whose gravitational well you happen to be in.
The Intrepid Space Pilot in your question happens to be in an orbit already, its just that that orbit happens to pass through the surface of the star http://www.shrapnelgames.com/ubb/images/icons/icon7.gif In order to stay in orbit, all the spacecraft must do is miss the star. To do that, the spacecraft need only dodge sideways one star-radius. It will then skim past the edge & go flying out, slow, fall back, and zing past the opposite edge.

Now, lets say you want to orbit an object that's 30,000Km wide. Since we are heading straight for it at the moment we must move sideways 15,000Km before we hit. If our ship is one second from impact, we must accelerate to 0.1c (10% the speed of light) in one second, then we can cut engines and be in orbit.
By accelerating to 30,000Km, in one second, we average 15,000Km/s, and in the one second before we hit, we've slid one star radius to the side, and fly past.

If we are nice and far away, such as near pluto's orbit, then we will have weeks to months before we reach the (30,000Km)"sun" (light takes 7 hours to get to pluto, and we're not going to be going anywhere near lightspeed)
divide the 15,000Km by 2 months, and we have:
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>No-calculator math time:
2 months= 60 days
=60*24 = 1200+240 = 1440 hours
=1500 x 60 = 60000+3000 minutes
=60000 x 60 = 3,600,000 seconds
15,000km / 3,600,000 seconds
=15 km / 3,600 s
= 15 /3.6 m/s
= about 5 m/s
= Jogging Speed.
<HR></BLOCKQUOTE>
So, even a ship without engines coud merely open a door & vent some atmosphere, to get a boost to that speed.

All you have to do is scoot sideways the width of your target & you're in orbit. Very Hot & Very cold at times, but an orbit nonetheless.

Re: Balck Holes too soft
 

Thanks!

Stupid Sci-Fi shows should try to be a bit more accurate about black holes. http://www.shrapnelgames.com/ubb/images/icons/icon7.gif

Re: Balck Holes too soft
 

Excellent SCI-FI book -

Light of Other days
by Arthur C. Clarke, Stephen Baxter http://images.amazon.com/images/P/08...1.LZZZZZZZ.jpg
Its about wormholes. Fascinating read.

[This message has been edited by AJC (edited 31 March 2001).]

Re: Balck Holes too soft
 

Sheesh next time I need a lesson in orbital mechanics for a sci-fi roleplaying game or a piece of fan fic, I'll remember to ask here. &lt;G&gt;

Re: Balck Holes too soft
 

&lt;Red Dwarf&gt;
Thing about space, right, is it's black. And the thing about black holes, right, is they're black. So how you meaent to see 'em then?
&lt;/Red dwarf&gt;


Sorry, it was all getting beyond me=-)

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--
There is an exception to every rule. Including this one.

Re: Balck Holes too soft
 

I just watches four episodes of Star Blazers yesterday. Their mission is to travel around 200,000 light years in less than a year. That's a pretty good distance considering that ST:V'Gr is gonna take around 70 years to travel just 70,000. Oh, I just figured it out. They made their first space warp from the moon to Mars and covered several thousand light years. :-)

Re: Balck Holes too soft
 

black holes are tecnically a pain in the *** to detect, but in the case of light if matter was caught in the accreation disc you could see it and then recognize the fact that a dense peiec of matter was at the center (ie. a black hole) BTW listen to Suicide_Junkie for the most part hes right http://www.shrapnelgames.com/ubb/images/icons/icon7.gif

Re: Balck Holes too soft
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Their mission is to travel around 200,000 light years in less than a year.<HR></BLOCKQUOTE>

I hope that wasn't a straight line distance.
Since [our] galaxy is only 100k LY across, that would put them in the middle of nowhere no matter which way they went. http://www.shrapnelgames.com/ubb/images/icons/icon7.gif

--------------------------------

Black hole detection:
If your black hole didn't have an accretion disk, and there was nothing in orbit (or even nearby), then it would be difficult to see indeed.
There would be a slight distortion from gravitational lensing around the edge of the hole, but you'd have to be looking right at it.
The ship would be slightly stressed from gravitational shear, but it it was noticeable over the air & people inside, it would be too late anyways...

But the main thing is:
This black hole is in the middle of nowhere, since there is nothing in the area to form an accretion disk. That means you'd have no reason for going there in the first place, & would never be in that position.

If you were travelling through an SE4 warp point to get to a BH system, then you'd have something to compare your movement to.
Since the WP is at a fixed distance from the hole, and likely provides no momentum to your ship, you would immediately start falling towards the hole.
What you would see is the WP moving away from you.
So, you:
A) full thrust for the WP & go home right away.
B) Assume you're being pulled by gravity & not an alien tractor beam, so you thrust sideways and go into orbit.
From your orbit & seeing the motion of the stars, you figure out where the hole is & what its mass is. Having mapped the system, you look for other WPs and then report to the empire for further instructions.
Note that the orbiting of the hole is easy & immediate.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Black holes are tecnically a pain in the *** to detect,<HR></BLOCKQUOTE>
Well, Black holes are a pain to detect, sitting on your home planet http://www.shrapnelgames.com/ubb/images/icons/icon7.gif if you're flying around in your spaceship inside the BH system, and have a WP to compare to, its mindless busywork to detect and map the thing.

[This message has been edited by suicide_junkie (edited 02 April 2001).]

Re: Balck Holes too soft
 

I thought they found black holes by looking for what was not there, no light where there should be some. I know they use x-rays and heat measurements also but I thought the absence of light was the main indicator.

Re: Balck Holes too soft
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>I thought they found black holes by looking for what was not there, no light where there should be some. I know they use x-rays and heat measurements also but I thought the absence of light was the main indicator.<HR></BLOCKQUOTE>
Very good.
the point you're missing is that they knew something is there, just not what it could be. If you look out into the depths of space at a black hole, you don't see much at all, and move on. If you see a star going in little circles, but nothing else, then you look closer and find that theres got to be a star-sized mass right there, but we don't see any light. Probably a black hole.

If the hole is sitting all alone, then it is almost impossible to detect. When your ship goes through the warp point, the hole is no longer alone, you and the warp point are there, & you can quickly see somethings amiss and conclude that it's a Black hole

Re: Balck Holes too soft
 

Of course I ment detection from Earth, but a quick point of order all black holes have an accreation disc, this area in with space is warped by the intence gravity exists wether there is something there on not the size of this area is determined by the overall desity of the hole the shape is determined by its rotation, also time is warped arount the hole this may affect how quickly the crew of a ship can respond and how quickly the signal they transmit will reach the general empire but in general loosing a ship to a black hole wouldn't be a common thing if the captain has some idea of stellar cartography and how vectors work, if he/she doesn't he/she shoudent be in space!

Now to the statment that black holes are in the middle of nowhere, not really, black holes are thought to exist in the center of our galaxy. Since early stars witch would form early in the universe time scale would be massive black holes should be damn near everywhere, assuming that the large stars were even half as plentiful as the ones witch exist now they may in fact be in the area of several thousand in the general vacinity of Sol (an estimate I will admit).

Suicide Junkie may I ask where you knowlege of stellar phenomenon is derived?

Re: Balck Holes too soft
 

Tee-hee-hee, cool thread! To throw another twist in, did you know that is it perfectly possible (at least theoretically) to make minute BHs?

A BH forms when the gravitational forces in a region of space become so large that the energy required for anything to escape becomes infinite.

Normally, the only way to do that is to pile so much mass up in a small volume that gravitational collapse results (ie big stars going nova, then collapsing back all the way)

But...on totally the other end of the scale, hands up those who know which parameter of a photon is inversely related to its energy?...Yes, you boy

Please Sir, wavelength!

Correct, boy! So, as wavelegth decreases, energy increases. As e=mc^2, we see that a photon of a given energy can be said to possess the equivalence of a certain amount of mass (as well as a tiny amount of "real" mass - thats why solar wind works).

A photon can also be said to occupy (on average) a small, finite volume of space at any time. It therefore possesses a calculable "density" (mass/volume=density, e=mc^2, =&gt;(e/c2)/volume=density).

If its wavelength can be sufficiently reduced, and its energy thus increased to the point where that density is high enough to cause gravitational collapse, voila, a microscopic BH!

In case you are wondering, yes photons DO undergo gravitational interactions, hence the already referred-to "gravitational lensing" effect, so this is (sort of!) feasible

I seem to remember reading that the particle accelerator that could actually get a photon up to the required speeds would need to stretch out about as far as the orbit of Pluto... so no worries just yet!

Re: Balck Holes too soft
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by TallTroll:
But...on totally the other end of the scale, hands up those who know which parameter of a photon is inversely related to its energy?<HR></BLOCKQUOTE>

Actually, I suspect you wouldn't be able to get a photon pumped up to a high enough energy to collapse it into a black hole. High-energy gamma rays have a tendancy to decay into electron-positron pairs (the reverse of the antimatter annihilation reaction), with the chances of pair formation going up with the photon's energy. I've never heard of the possibility of black hole formation, so I suspect that photons would decay before they reach that point.

Re: Balck Holes too soft
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Now to the statment that black holes are in the middle of nowhere, not really,
...
they may in fact be in the area of several thousand in the general vacinity of Sol (an estimate I will admit).
Suicide Junkie may I ask where you knowlege of stellar phenomenon is derived?<HR></BLOCKQUOTE>This is kind of late, but since the thread's resurfaced, and I've noticed that comment, I should respond.

Sirkit, you have almost answered your own question here.
I was not implying that all black holes are "in the middle of nowhere", or denying that there were any near any specific place.
I merely said that the ones that happen to be solitary are hard to detect. If the hole is drifting alone, it will not have an appreciable accretion disk (since there is no nearby source of gas, such as a red giant), and its gravitational influence on its distant neighbours will be minor.
Gravitational lensing would be noticable, but you'd have to be looking right at the hole while stars move behind it.

And yes, I do know that the center of the galaxy is likely a giant black hole, but we were discussing star-scale BHs, so I didn't mention it.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>also time is warped arount the hole this may affect how quickly the crew of a ship can respond and how quickly the signal they transmit will reach the general empire<HR></BLOCKQUOTE>Sure, a little bit, but even if your black hole was large enough that you could survive the gravitational shear past the event horizon, the delay would only become noticable to humans (fractions of a second) when the ship is less than a few seconds from the event horizon. (eg. from aBHoT)
More important would probably be the fact that the message would take decades to reach home without using the Warppoint you arrived from.

Most of my info in this thread came from "A brief history of time" - S. Hawking (some good blackhole stuff & I belive I quoted it somewhere below), or "Scientific American" magazine for general ideas.

Re: Balck Holes too soft
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by BeeDee10:
Actually, I suspect you wouldn't be able to get a photon pumped up to a high enough energy to collapse it into a black hole<HR></BLOCKQUOTE>

I thought they were designing a new super collider for that very purpose? i have been hearing an awful lot about 'mini black holes' in the press in the Last 12 months or so. or is that a different principal that is being discussed in the popular science rags these days? I recall them also theorizing that they could use a laser to create mini-black holes.. probably in effect by adding energy to photons, id guess.

------------------
"...the green, sticky spawn of the stars"
(with apologies to H.P.L.)

Re: Balck Holes too soft
 

Puke,

I think you are right. Check this link
http://www.nature.com/nsu/011004/011004-8.html

The Large Hadron Collider at the CERN physics lab near Geneva is 27 kilometers in diameter. The article states that they will create a black hole every second.


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In difficult ground, press-on;
In encircled ground, devise stratagems;
In death ground, fight.
Sun Tzu (circa 400 B.C.)

Re: Balck Holes too soft
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Kadste:
The Large Hadron Collider at the CERN physics lab near Geneva is 27 kilometers in diameter. The article states that they will create a black hole every second.<HR></BLOCKQUOTE>

Right, but photons are not hadrons. They're leptons, IIRC. Hadrons are big, massive things like protons. They can be accelerated to any energy level one likes; it's only when they're collided at high speeds that black holes might get made, depending on how physics turns out to work (it's not _known_ that black holes will be produced, it's only predicted by some of the proposed theories).

Re: Balck Holes too soft
 

&gt;&gt; High-energy gamma rays have a tendancy to decay into electron-positron pairs

True, the Pair Formation Threshold is only 1.022 MeV, but note that this only makes it POSSIBLE for a high-energy photon to decay. An interaction with matter is required to trigger the decay.

Pair production is a collision process, so as long as you are able to keep your photons away from heavy nuclei, you'll be fine.

The real problems occur when you consider that you need either a ridiuclously strong field, or a massive accelerator to achieve the required energy.

We either need to learn to produce stable magnetic fields many orders of magnitude stronger than anything we can manage today, or produce really high quality vacuums. If you need an accelerator than can realistically be measured in AU, you don't have much chance of getting a photon to survive the round trip without hitting something, unless you can COMPLETELY empty the chamber. Even interstellar space has a density of about 1 - 100 atoms/cm3.

As Pluto is about 38.5 AU away (approx. 3.6 billion miles, I think), you can see that you need a VERY clean acceleration chamber for any significant chance of a photon surviving the trip.

Theoretically possible to do it then, but much engineering needed first

Re: Balck Holes too soft
 

Going back to the original topic of this thread I would say that Black Wholes should neither pull in ships or leave them be. If we were talking in the game sense doesn't a turn just stop time for you and start it for the next player? I would say that in this case the black whole should only slow down the ships perhaps makeing movement half of normal. The damage that they do should also be increased to compensate for the new larger ships being built in the various mods that have been released. No ship should be able to survive a black hole no matter what the size!!!

Re: Balck Holes too soft
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by TallTroll:
True, the Pair Formation Threshold is only 1.022 MeV, but note that this only makes it POSSIBLE for a high-energy photon to decay. An interaction with matter is required to trigger the decay.<HR></BLOCKQUOTE>

Cool, I wasn't aware of that detail.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>you can see that you need a VERY clean acceleration chamber for any significant chance of a photon surviving the trip.<HR></BLOCKQUOTE>

But how does one "accelerate" (actually, add energy to) a photon directly once it has been emitted, without having it interact with matter? The only thing I can think of offhand would be by dropping it down an intense gravity well, and it seems somewhat perverse to contemplate sending a photon into a black hole in order to boost it to the energy level necessary for it to turn into a black hole. http://www.shrapnelgames.com/ubb/images/icons/icon7.gif
I suppose you could also accelerate _yourself_ to near lightspeed, so that the photons you encounter along the way will appear to be so intensely blueshifted that they turn into super-high-energy gamma rays from your frame of reference, but I suspect it will be hard to report what you observe afterward.
I just dabble in this stuff, though, so if I've made any further oversights I will renounce my skepticism gracefully. http://www.shrapnelgames.com/ubb/images/icons/icon7.gif