Blue Fire

The fact of the matter is that we have never observed the complete evolution of a star or galaxy. Thus we cannot know with 100 percent certainty what that process is. But, there are sooooo many stars in varying stages of development, and there are soooooo many galaxies in varying stages of development, and therefore we have had soooooooooooo many observations that we are pretty darned sure about what the whole story is. Sooooo sure that most astronomers are willing to accept it as fact.

 

Even a child who has not witnessed the entire life cycle of a tree and who has not been educated about it either can look at a forest and be pretty darned sure that he sees seedlings, saplings, young trees, old trees and dead trees - after, of course he has seen a bunch of them in a bunch of forests.

Perhaps a visit to Wikipedia will help: http://en.wikipedia.org/wiki/Cosmological_redshift

 

The discovery of the linear relationship between redshift and distance coupled with a supposed linear relation between recessional velocity and redshift yields a straightforward mathematical expression for Hubble's Law as follows:

 

v = H_0 \, D,

 

where

 

* v is the recessional velocity, typically expressed in km/s.

* H0 is Hubble's constant and corresponds to the value of H (often termed the Hubble parameter which is a value that is time dependent) in the Friedmann equations taken at the time of observation denoted by the subscript 0. This value is the same throughout the universe for a given comoving time.

* D is the comoving proper distance from the galaxy to the observer, measured in mega parsecs (Mpc), in the 3-space defined by given cosmological time. (Recession velocity is just v = dD/dt).

 

Hubble's law is considered a fundamental relation between recessional velocity and distance. However, the relation between recessional velocity and redshift depends on the cosmological model adopted, and is not established except for small redshifts.

 

For distances D larger than the radius of the Hubble sphere rHS objects recede at a rate faster than the speed of light:[14]

 

r_{HS} = \frac{c}{H_0} \ .

 

Inasmuch as the Hubble "constant" is not constant at all, but varies with time in a manner dictated by the choice of cosmological model, the radius of the Hubble sphere may increase or decrease over various time intervals. The subscript '0' indicates the value of the Hubble constant today.

The key concept here is that the Hubble constant is not really constant. If I understand your question correctly (and there's no guarantee of that since you say I didn't answer your question with my previous post), then the variation of the Hubble constant over time and the Hubble sphere increasing or decreasing over time seems to have it covered. If I still don't understand your question, then I'm afraid I'll have to give up and admit defeat.

[snip]

Mars had water. In fact, Mars had more water per ratio than Earth, which could mean that the same number of comets carrying water impacted Mars as they did Earth, since Mars is smaller, it would have more water.

Indeed we know Mars had water, and we know it still does have water at least in ice form and probably water vapor (as ice sublimates to vapor), but I'm wondering where you got your information that Mars had More water per ratio than Earth? I did a quick search on this and came up with only vague guestimates and speculation with no definite claim to how much water Mars had in the past. I'd be interested in any further info you could point me to.

My understanding is that gravitational fields ARE curved spacetime. Mass curves spacetime. Using the phrase "gravitational fields" is just another way of referencing curved spacetime. Spacetime curvature is the result of Mass. So, spacetime curvature and gravitational field are essentially the same thing. Gravity is often referred to as a "force". But this isn't strictly true according to Einstien - there is no "force" between the Earth and the Sun, for example. The Sun has lot of mass and thus curves the spacetime around it. Earth is revolving around the Sun because it is following a "straight" line in curved space. Travel in a straight line around the the Earth and you will find that you are actually traveling in a curve around the curved surface/space of the surface of the Earth.

 

So, light definitely is affected by a gravitational field - this has been confirmed by observation many, many times. But that gravitational field is simply the curvature of spacetime that massive bodies cause.

 

Light from distant galaxies (or near ones) or light from any source no matter how far away (or how close) travels in as straight a line as possible in curved spacetime. The light from a street lamp travels to your eyes in a slight (VERY slight, insignificant really) curve because it is following the curved spacetime that Earth itself causes.

 

The speed of light never changes in a uniform medium. In the empty expanding spacetime between distant galaxies, the speed of light never varies. Of course, if the space it is traveling through is expanding, then it will take longer to get through it only because it has farther to travel. Also of course, there will indeed be a red shift in this case.

I would submit that often routing and air traffic control would have a big impact. Flights in the U.S. often do not fly the exact same route to and from destinations in order to avoid airspace conflicts according to air traffic control. Thus, one direction may indeed take longer because the airplane is traveling a slightly different and longer route that you may not notice as a passenger.

[snip]

However, when the light interacts with gravity and is time dilated, that is only relative to some other / external reference frame.

 

So, the answer is no. A photon interacting with gravity will not travel back in time.

How is light time dilated by gravity? My understanding is that a photon always travels at c regardless of one's frame of reference - anyone in any reference frame will always measure the speed of light to be c, if the light isn't impeded by some medium (see below). A photon passing close to a black hole is not slowed down - it's path will be severely bent according to the curvature of space caused by the extreme gravity of the black hole but it's velocity won't change. Light will, of course, slow down inside some medium it is passing through (like glass) but that is because the individual photons are getting absorbed and re-emitted continually.

 

Is my understanding flawed?

... [snip]

And you are always moving through time.

Unless, of course, you are a photon, in which case you would be moving entirely through space and not through time. It may be helpful to note that everything moves through spacetime at c. Of course, for most things, movement consists of some movement through space and some movement through time - sort of like traveling northeast in a car. Some part of your motion is north and some part is east. And some things like light travel due east (assuming east is space) with no motion north (time).

I knew some people that had a grand scheme, a big picture, and an ultimate plan. They believed that everyone and thing around them were part of it all. Alas, they are all dead now and their plans didn't pan out in the end.

 

Sorry, couldn't resist it.

 

Seriously though, any grand scheme would seem to require a grand schemer in whom (or what) I don't happen to believe.

Just a note about being able to tell the difference between gravity and acceleration:

assuming (from the OP)

if you were in a sealed windowless box (that had extraordinarily good vibration dampening) would you be able to tell if the box was simply sitting on the ground and you feel the 1g pull of the Earth or if you were in a rocket accelerating at 1g in a flat spacetime?

Yes! That is, if you had extremely sensitive/accurate measuring tools in the box with you. If you drop two balls, one from each of your outstretched arms, then you would find that each ball would drop toward the center of the Earth and thus trace out intersecting paths, if you were sitting on Earth. If you were simply undergoing acceleration (as in a rocket), the balls would drop exactly parallel to each other. Granted that, on Earth, the non-parallel drop of the balls would be very difficult to measure, but still detectable in theory.

It couldn't just be an "ordinary" human who happened to be a Primordial dwarf?

I'd say that would be highly unlikely since remains of multiple individuals were found of widely varying ages at the time of death, each consistent with the diminutive size range of these people.

 

And, now this from SciAm Observations:

The Palau bones certainly underscore just how variable modern humans are. But do they really spell trouble for the theory that the Flores hobbits represent a new human species? I don't think so. Although Berger estimates that the Palau people had a brain size close to the low end of the modern human range, that's still a lot bigger than LB1's brain, which was on par with a chimp's. And hobbit critics have yet to come up with a genetic disorder that can account for LB1's diminutive brain size and all of her other odd traits. Furthermore, some aspects of LB1's skeleton are simply not found in H. sapiens. Her wrist bones, for example, look just like a chimpanzee wrist and nothing like our own. This is particularly strong evidence for LB1 belonging to a different species, because the wrist takes shape in the first trimester of pregnancy, well before most growth disorders could affect it. According to the National Geographic report, Berger's team has yet to study the wrist bones of the Palau folks.

 

One last tidbit: according to a story on ScienceNOW, other excavations on Palau have turned up individuals of normal body size that are the same age as the tiny people Berger found. To quote from the story:

 

"...archaeologist Scott Fitzpatrick of North Carolina State University in Raleigh, who has worked in Palau for a decade, says he doesn't think the bone beds represent a true population. In a site only 4 kilometers from Berger's caves, he has excavated the burials of Palauans of similar age--and normal stature. That would seem to rule out isolation and island dwarfing, he says. 'It would be very unusual to have a group of people living in close contact with a normal size population who evolved to be smaller.' Instead, 'the most parsimonious explanation is that they were Palauans with a genetic anomaly leading to small people who were buried in a clan or family plot.'"

From this it would seem that the "doubts" are still in favor of the "Hobbits".

National Geographic Channel is running a special on the discovery of Homo floresiensis right now as I write. I think it has been on before and that I've seen it before, but there's always something ya miss the first time around.

I used to have a thing against titles like Dr. in a college setting. I was an older student when I returned to college for an advanced degree, and I noticed that some instructors would introduce themselves to their class by writing "Dr. so-and-so" on the blackboard and then proceed to address their students by first names. The first time one of those instructors did that to me, I politely corrected him with "Ah... that's Mr. Me, please." After that we got on quite well on a first name basis for everyone.

 

I then tried an experiment at 2 different highschools for which I subsequently did substitute teaching. In school A, I followed school policy in insisting on a "Mr." in front of my name. In school B, I asked the students to call me by my first name. I found the students in school B more difficult to control at first, but in the long run, I had even more control of and respect from the school B students because it apparently was a more personal affront to me (from the student's point of view) to misbehave and/or disrespect me. I was able to be much more effective as a teacher/leader when it was all personal instead of the formal air inherent in the use of titles at school A.

 

Just my 2 cents.

I don't think all the evidence is in quite yet - there will surely be more excavations and finds to argue over. Note that the "new finds" that the OP mentions were found on a different island. And, the article at NewScientist also presents opinions that cast doubt on those casting doubt that Homo floresiensis is a new species of human. I'm sure the debate will continue in earnest in scientific circles to get at the truth even as media reports continue to hype all hints of controversy on such a unique subject as "hobbits."

I used to think that time was merely the speed at which the mind thinks. But I'm better now.

Ranting can be cathartic! And sometimes, when you look back at that ranting, it can inspire a useful perspective.

 

It may be that you are here, in this forum and in college, for a similar reason that I'm here: as Socrates once said, "The unexamined life is not worth living." So, I examine it. And I find that thinking for myself is worth it, even if I don't find the answers as I'd like them to be. And, I've learned that I'd rather be miserable with the truth than blissful with ignorance. But that's just me.

Just a slight correction, since you mentioned Einstein and that gravity is a force of attraction. Einstein theories actually blew that notion (that gravity is a force of attraction) away many decades ago. Accordingly, contrary to Dictionary.com, gravity is Not a force of attraction. Gravity is the effect that mass has on spacetime. Mass Warps space and time (spacetime) - the greater the mass, the greater the warping of space time. Envision a cannonball sitting on a trampoline. The cannonball "warps" the fabric of the trampoline like the Sun warps the fabric of spacetime. Now flick a marble toward the cannonball from the side of the trampoline. Picture the marble "falling" into the depression (warping) that the cannonball makes on the surface of the trampoline. The marbles dips into the depression and rolls around and around the cannonball. As you can see, it does this not because of any attraction between the cannonball and the marble but rather because the marble is simply following a "straight line" on the curved surface of the trampoline. Thus the Earth is simply moving through the curved space around the sun - there is no force of attraction keeping the Earth in orbit around the sun.

If the universe is expanding, what is it expanding into?

 

Until now, I always thought it was *space*-time expanding into something. The post above is a new thought for me, space is already there, matter/energy expanding into it.

The universe is expanding because space itself is expanding. In general, galaxies are moving away from one another because the space between them is expanding - they are not moving Through space, they are simply moving with the expansion of space. This is similar to the way pennies that are pasted onto a balloon will move away from each other as the balloon gets bigger and bigger. The pennies aren't moving across the surface of the balloon, they are just moving as a result of the expansion of the balloon's surface. If you can imagine that the surface of the balloon Is the universe, then you can see that the surface isn't expanding Into anything - the surface is all there is. Now try to translate this into thinking about a hypersphere (4D, excluding time) expanding. That might help to understand the theory. At the time of the Big Bang (meant to be an inclusive term of inflation theory), there was no space, no time - they were created and continued to expand, and this was all there was to our universe. Of course it is possible that our universe expanded and continues to expand into something "else" but that something else would not be our universe as we understand it now.

After some more research, I found this at Sky & Telescope:

Early Danjon-number estimates that we're getting range from 2.5 to 3. Roger Sinnott, our lunar-eclipse data master, used the reversed-binocular method to get a preliminary brightness estimate at mid-eclipse: magnitude –3.4. (His final value awaits his calibration of how much the binoculars actually diminish light when reversed, done by comparing stars.) In Brazil, experienced lunar-eclipse observer Willian C. de Souza used the same method and got magnitude –2.4 at mid-eclipse, though with cloud interference. John Bortle got magnitude –3.2.

According to NASA [http://sunearth.gsfc.nasa.gov/eclipse/OH/Danjon.html]:

The French astronomer A. Danjon proposed a useful five point scale for evaluating the visual appearance and brightness of the Moon during total lunar eclipses. 'L' values for various luminosities are defined as follows:

L = 0 Very dark eclipse.

Moon almost invisible, especially at mid-totality.

L = 1 Dark Eclipse, gray or brownish in coloration.

Details distinguishable only with difficulty.

L = 2 Deep red or rust-colored eclipse.

Very dark central shadow, while outer edge of umbra

is relatively bright.

L = 3 Brick-red eclipse.

Umbral shadow usually has a bright or yellow rim.

L = 4 Very bright copper-red or orange eclipse.

Umbral shadow has a bluish, very bright rim.

The assignment of an 'L' value to lunar eclipses is best done with the naked eye, binoculars or a small telescope near the time of mid-totality. It's also useful to examine the Moon's appearance just after the beginning and before the end of totality. The Moon is then near the edge of the shadow and provides an opportunity to assign an 'L' value to the outer umbra. In making any evaluations, you should record both the instrumentation and the time. Also note any variations in color and brightness in different parts of the umbra, as well as the apparent sharpness of the shadow's edge. Pay attention to the visibility of lunar features within the umbra.

[bold above is mine]I would have rated this eclipse at about L=3.5 because I saw mostly orange and just a tinge of blue on the Moon's edge just after totality began. I can only think that the atmospheric properties/effects directly between an observer (like moisture content, density, etc.) and the Moon do indeed have significant impact on what different observers see, With or WithOut equipment, though I have yet to see any specific explanation in print anywhere yet. Maybe I'm not looking hard enough. On the other hand, it appears to be a valid phenomenon since (from NASA site):

Observers are encouraged to make Danjon brightness estimates and to report them to Sky and Telescope and to Dr. Richard Keen (richard.keen@colorado.edu).

I've also read that you might see some turquoise color at the edges of the moon just before and after totality in a lunar eclipse. I thought I could make out just a tinge of turquoise myself. This is supposed to be due to the light reaching the moon through the Earth's ozone layer which tends to absorb red but allows blue to pass more easily.

I've noted discrepancies in reported brightness and color of the eclipse between observers at various locations. For example, some say the Moon was brighter than previous eclipses and some say it was darker. The Sky & Telescope website reports that it was brighter and has a comparison pic of last year's eclipse and this one. Their pic of this year's eclipse pretty closely matched what I saw.

 

Is it possible that the viewing location would account for widely varying observation reports of a total lunar eclipse? I can, of course, imagine the effects of light pollution, cloud cover, etc., but even those folks who say they had dark skies and no cloud cover disagree over brightness and color.

That shot of the Moon dipping behind a peak is indeed inspiring! I got to see the vast majority of the eclipse (some clouds for a while), but alas I didn't get any pictures. So I appreciate everyone else's efforts. I never get tired of lunar eclipses, and I've see a few in my time. I don't understand why everyone doesn't get into them, but I have several friends who just never bother keeping track of these things and don't look up.

 

I couldn't detect the turquoise band with my naked eyes, but my 12x binoculars did the trick.