La Lune

I've recently come across another cool website, this one is a click-able map of the moon. You can find it at inconstantmoon.com what makes this site better than say, Google moon, is simply the huge amount of data at your finger tips. As well as the usual, click-able and zoom-able maps, with overlays of craters and Apollo landing sites there are things like the map above, which shows the amount of TiO2 in the moons surface, others show the thickness of the crust or the gravitational anomalies. Unfortunately no magnetic data yet, so its not possible to search for any magnetic anomalies, especially in the Tycho region (note for non sci-fi buffs read 2001).

To have a play around click on atlas, then just press buttons on the side bar to the right.

Mega Science

The UKs latest large piece of Scientific hardware is now up and working. The Diamond synchroton will be used to probe the nature of materials on the smallest scales, allowing new insights into how materials behave on the atomic level, as well as probing the structures of biological samples. Hopefully leading to better smart materials and new pharmaceuticals. The BBC has a reasonably good story covering the main talking points over here.

A synchrotron works by accelerating electrons to near the speed of light, confining them with magnetic fields they are forced around and around a circular ring. As they travel round the synchrotron the electrons emit electro-magnetic radiation in the X-ray and gamma ray region of the spectrum. At speeds close to the speed of light strange things begin to happen, one of which is that the light emitted is affected by Special Relativity and is boosted in wavelength by relativistic effects, another is that the radiation pattern becomes highly collimated. Because of these two effects synchrotrons are the brightest known sources of X-rays. Just another real life example of how an abstract physical concept has real world application.

Oh and in case your wondering (in light of many recent posts), no, Autodynamics cannot explain the light given off by a synchrotron, in fact it can't even match the observed motion of electrons around the synchrotron, oops.

Online Games - Part 2

As if the last batch wouldn't cause major losses of productivity here are a few more games worth at least 5 minutes "contemplation". Without further ado, onto the list:


The Adventures of Fancy Pants Man - Simple platformer along the lines of sonic the hedgehog, pretty cool looking.



Novel Concepts TD - Not sure what the real name of this one is, its really simple, you have to kill a horde of "creeps" using cannon, towers etc. It looks easy but is incredibly difficult to master, just check out the forum, there are actually loads of people in there discussing strategy ffs. Despite this I like it.


Word Shoot - Fancy some education while you kill the rampaging hordes? No me neither, but here you go anyway, basically you have to type words as fast as you can. The words corresponding to enemies approaching, if you get the word right you kill them. Improved my touch typing in about 3 minutes.

AD Update

As it now seems that I am persona non grata over at the AD discussion board (my messages are blocked, not even any replies by email now) I think its about time I wrapped things up. To this end I'm working on a large post, listing the problems with AD that I and others, JPS, ibaDaiRon etc have spotted. Where possible I'm going to let the ADherents talk for themselves. I'm hoping that eventually the post will make it to the top of the Google search list for Autodynamics, so when it appears any help you out there can give would be gratefully appreciated. Thanks.

Note: I have just seen the latest from DdH over at the discussion board:

Where does the rage from the AD bashers come from?

I really wonder. If we are so crazy, then no one should waste their
time coming here to be dragon slayers.

If anyone has a good explanation, I'd love here it. I'd don't understand why these people wouldn't feel stupid or embarrassed.

Anyways, I will start banning these guys now that we know they have some real emotional issues. From the blogs, we know thaty have a fixaction on bashing AD (for no good reason other than being disfunctional), they have no interest in learning it, and they can't even grasp the simple concepts of physics let alone AD.

They are simpletons who are trying to find the golden sword to kill AD. These days it's the velocity sum.

I have already started rejecting their messages. Some are in the stage of "AD people are uncivil and therefore ruin any chance of having outside people study AD". Boy, that's NOT a new one.

Next is to ban them.

Get a life people! Do something good for human kind. Stop being so disfunctional.

-David

Unfortunately as DdH is not one to hear any dissenting opinions I can't respond to that on the message board, the sole purpose of which appears to be to hold a series of ass-kissing and toadying responses to DdH. So here is my response, I know he'll get to it in a day or so.

The reason I have taken an interest Dave, is because I'm a good old rational scientist, I believe that the best theory is the one that closest matches reality, using this as a yardstick AD is complete rubbish, the more people that have that explained to them the better. No one wants to end up like Carezani, wasting over 60 years and enduring many hardships because they didn't understand something, unfortunately there are plenty of people with too little knowledge of science and mathematics that your mumbo jumbo could confuse.

This is science not religion, all theories are not equal, just because you get prissy when someone points out problems with your theory is not going to stop anyone objectively examining it. There is no rage here, the word that best sums up my feelings towards your group is pity, you have gone too far to accept that you were wrong and will now waste the rest of your lives on a pointless pursuit, no amount of evidence, no logic or mathematics can now dissuade you from this path. Its such a waste. My only aim is to point out the obvious problems so that others do not waste their own time, I think the facts speak for themselves, people can decide for themselves once they have seen them. I am fairly sure what the outcome will be.

Oh and by the way, thanks for your continued patronage of this blog.

Cool Sky Map

I came across this cool bit of astronomy software the other day. There seems to be two versions about sky-map.org and wikisky.org. They seem to be identical. They allow you to slide around the night sky with or without constellations and to search for your favourite night sky objects (like NGC galaxies), so far, so like any other planetarium software. The cool thing with this software is that it also has the SDSS imaging survey built in. So you can switch to SDSS mode and look at the actual images produced by the Sloan survey. Unfortunately the SDSS doesn't cover the whole sky so many of my favourites aren't in it.

This is really only the start, we have been talking about software like this at work for awhile now, the ultimate (wet) dream for astronomers would be software like this that started in planetarium view but over layed survey areas from the various surveys, or even little symbols to show where the HST had been pointed at an object (The first steps have been made to do this in the Astro Photo section, check it out). You would then be able to click on the little links to take you directly to the data, it would make life much simpler than searching dozens of archives to find out if what you would like to do has already been done, saving time and money for eveyone, plus it would make a great toy for everyone to enjoy.

Give it a go, there's probably plenty of weird things to be seen in the SDSS images.

The Universe, All Of It On Your Screen

Here is an image that the ICCmofos had on their door a while back, showing distances to objects stretching from the Core of the Earth to the edge of the observable Universe. Using a logarithmic scale it shows the distances to objects such as Earth orbiting satellites, the planets, nearby stars, galaxies, clusters of galaxies, SDSS galaxies and the Cosmic Microwave Background. It is very cool in a very nerdy way. Unfortunately I can't seem to track down who made it right now.

Of particular note are the SDSS galaxies shown at the top of the page as blue dots, the filamentary structure of the Universe on large scales is immediately obvious. I still think it is pretty amazing that we're smart enough as a species to measure such things and then are able to plot the distances to anything in the Universe on only 3-4 sheets of A4.

Addictive Online Games

Thanks to the wonder that is stumble upon I have been coming across more and more fun but distracting online games. Give them a try at your peril, they are a major time sink.

Virus 2 - Simple board like game where you have to make your virus take over the whole board.

Tetris - The Daddy of them all. Needs no introduction.

Puki - Kill a rampaging horde of what appears to be toddlers, using a laser gun. Strangely reminiscent of a "philosophical/hypothetical" question raised by CMB, "how many 5 year olds could you kill, if they kept coming at you and you had to?".

Matter - Simple block arranging pattern matching game. Think along the lines of the challenges on the Krypton Factor, if you know what that is. My best so far is 1080 (Update: 1131) points.

Dots - Connect dots to make squares, make more squares than the computer.

More From The ADherents

So DdH has replied to my post on the discussion board, with an email, he apparently doesn't want the members of the board to see it. Here it is, with my response below.

Yes or no to the question: are you SINCERELY interested in learning about AD?

Thanks,

-David

My response:

Yes I am sincerely interested in learning about AD, that however does not mean that I believe it is correct.

What you actually mean is if you let me back in will I stop being a naughty boy and asking impertinent questions, right? The answer to that is categorically no. That is not how science works, all theories are fair game, if AD cannot withstand the rough and tumble of experiment and investigation then it doesn't deserve any further work.

I'm guessing this ends my participation in the group, its good to see others are continuing in a similar vein though.

Mispronounced Domain Names

A list of 5 of my favourite (to date) mispronounced domain names:

1. Therapistfinder.com - Er, need to find a therapist?
2. Whorepresents.com - Find out the agent for a particular performer.
3. Cummingfirst.com - Cumming First United Methodist Church.
4. Scatissues.com - The website of SCA tissues.
5. Penisland.com - Sells pens.

Does anyone else have any good ones?

Medical Madness

Every once in a while a story comes along and you have to check that its not April Fools day, this is one such example from the BBC. The President of the Gambia and his health minister claim to have a cure for AIDS that works in 3 days and is a secret blend of medicinal herbs. There are very few details except that they claim that patients taking their potion have put on weight and their physical condition has improved. One patient, university lecturer Ousman Sowe had this to say:

I've noticed I've increased weight substantially over the last 10 days. I am no longer suffering from constipation, but we have yet to receive result of the tests.

I have 100% confidence in the president and I'm taking the medication with all confidence.

Sounds convincing to me, don't get me wrong it would be great if a bunch of herbs could cure a disease modern science is still years away from destroying, but I just don't buy it. To me it sounds exactly what you would expect from the placebo effect, this guy believes that the President can cure him so he feels better. This is exactly the reason why medicines are tested using the double blind technique, where neither the patient or the doctor involved knows if the real medicine or a placebo is being given. A quote from the President himself makes me even more skeptical.

I am not a witch doctor and in fact you cannot have a witch doctor. You are either a witch or a doctor.

So it would appear that while the President doesn't believe in witch doctors, he does believe that witches are real. Wow, I thought the US had it bad with their choice of leader.

Scientific Independence

More examples of White House interference in Science are beginning to appear now that the Democrats are in charge of congress. In particular it appears that the WH has been changing the wording of reports and ordering scientists not to use the words global warming in their talks or papers. For the full story click here. The White House's response, that it is only trying to provide balance to the debate is utter nonsense, there is no debate amongst anyone who has looked at the issue seriously, global warming is happening and it is being caused by humans. The only people who seem to disagree all seem to be in the paid employment of Exxon or some other oil company, like the quote says "It is difficult to get a man to understand something, when his salary depends upon him not understanding it".

Also potentially worrying is that the New York Times reported last week the WH is planning to place appointed officials in US government institutions to "supervise the development of rules and documents providing guidance to regulated industries". What this actually means is that political appointees are going to decide policy in organisations such as the Environmental Protection Agency, so you will get another round of Bush appointing industry insiders to watch over their own industries. Just wait for the dirtier skies, polluted water and soaring profits for energy companies as all of the last two decades of legislation are undone. It amazes me that a President held in contempt by a majority of his population, whose ideas have been dramatically rejected in a recent election, can still have the balls to go about another huge power grab.

Dirty Windows

The inescapable backlash against Vista has begun, even the BBC has pitched in with this article about just what you agree too when you install Vista. Most worrying to my mind are two statements in the agreement:

"this agreement only gives you some rights to use the software. Microsoft reserves all other rights"

and

"you may not work around any technical limitations in the software"

Hmm, so they (Microsoft) actually reserve all rights for anything you do on your machine with Vista, and if the software has any problems (which of course it is loaded with them) you are not allowed to come up with any work arounds to deal with the problem.

I'll stick with my Mac thanks.

Scientific Debate?

So there has been plenty of action on the AD discussion board of late. So the background is that I had posted a point that AD couldn't possibly predict the motion of charged particles at velocities near the speed of light, the kind of thing done every day in particle accelerators, now the choice of magnetic field and accelerating electric field used is well known, even if you didn't have SR you could work it out by trial and error. My point was that as we know SR matches the observations perfectly then reasonably AD should too, I also enquired about the fact that with the neutrino gone all of particle physics breaks down, as do all of the conservation laws of particle physics, here is my post:

Thanks Will that was my next question as well. :)

As Will has pointed out the existence of the neutrino is not proven by one single experiment or one single interaction. The existence of the neutrino is an unavoidable consequence of the standard model of particle physics, it doesn't just carry off energy in the reactions that you deride, but also spin and lepton number, all of which must be conserved during reactions. Even if there hadn't been a problem with reconciling energy and momentum in reactions it still would have been postulated to account for the apparent non conservation of these quantities.

So how does AD deal with the requirement to conserve quantities such as these in reactions without the existence of the neutrino?

DdH replied with this:

Take a look at Nucleus-Nucleus Collision at:

http://www.autodynamics.org/main/index.php
?module=pagemaster&PAGE_user_op=view_p\
age&PAGE_id=20&MMN_position=27:17

There you will find an explanation of particle collisions without the neutrino using AD while still conserving energy and momentum.

A question to your statement which I have heard for many years now:

Where does the idea that "spin and lepton number must be conserved during reactions" come from?

First, you have to agree and prove that all of those leptons and properties of leptons truly exist before you can conserve them. If the neutrino doesn't exist, then either the leptons count is wrong, the properties of leptons are wrong, or the equations themselves are wrong. The AD answer is the equation is wrong and the lepton count is therefore wrong.

Since particle accelerators are calibrated using SR, they are using the wrong equations and force the creation of leptons. Use AD, the neutrino is not needed and all particle interactions are explainable without the neutrino.

Please read the above article.

-David

The link of course does not answer my question. I then replied with this:

I think we have got onto two different topics here.

First the cyclotron, or particle accelerator issue. I'm assuming you agree that we do know how high the magnetic field and electric field has to be to keep electrons confined, these values have to change as the electron increases in velocity (and the theoretical values take into account the SR mass increase). These numbers can be gotten experimentally by trial and error if needs be. So what I think your saying is that for SR to be wrong but still precisely predict exactly what is observed there needs to be some other processes going on that exactly balances the "error" in SR to make it match the observed values of magnetic field and electric field. Though of course in this picture the exact opposite must be true for AD, it cannot predict the values, as the fixed m/e ratio shows, therefore there must be some unobserved phenomena going on which included would make AD match the observations. Its getting awfully contrived by this point isn't it?

The second issue I believe is similar, you are saying that not only is SR/GR wrong but so is particle physics/QM, but for some reason these theories when combined manage to reproduce the observations to the most mind shattering levels of accuracy. You are saying that lepton number is not a real conserved quantity or is not understood, but again because SR predicts exactly the right numbers, it must be that the choice of magnetic and electric fields are are producing some new particle or phenomena that makes SR exactly reproduce the observations.

You must really not be keen on the money being spent on CERN right? Billions and billions being spent and as far as you're concerned the machine itself is masking the true process. Do you have an experiment that could show the difference?

You can see why this is to put it mildly just a little hard to swallow. Physics is one big discipline, it really is impossible to change one area without altering others, as we see here.

Thanks

To which DdH had this to say:

Dear Mark:

I do have to give you an award for showing your true colors:

"most mind shattering levels of accuracy"

Could you quantify that scientifically? To me, that statement gives you away as an obvious dragon slayer here in our egroup. I don't even believe ANY experiment can say that and never will be able to say that. Things can look pretty darn good but "mind shattering"?, that is for people like my brother who is a writer of fiction. Only emotion and love or hate can generate such a statement as your's above, not scientific thought or discipline. You are in love with Einstein!

Did you read the article and study what is there? It looks like you didn't even click on it. "Reply" is not the link. Try the link this time.

You ask a question, we answer and have a paper on it, and you ignore it completely. What a way to study and learn AD!

We don't need a lesson in what the establishment says about accelerators. Carezani knows it better than the physicists themselves. That is why he wrote the article in reference. That is why we have this egroup. Not to repeat the mantras and mistakes of SR and GR, but to find their problems, correct them, and go on to a great future instead of a brick wall and endless tweaking in dead-ends.

Randall Meyer in his interview on our Science Watchdogs podcast said it best: "You can tweak any theory to do anything you want." SR and GR and the big bang and black holes and the grand daddy of them all neutrinos - they are all theories that literally have been tweaked to death.

This is an AD group to help study AD. Not SR. Please study the article sent and come back with questions. The answers are there.

Before you post and repeat what is repeated a 100,000 times a year in the establishment and universities, come back after you read Carezani's papers on Nucleus-Nucleus collision.

I will reject messages that spout off what we already know: that SR works perfectly. If it did, then Carezani would be a mechanical engineer enjoying his grandkids somewhere in Argentina. Believe me, there are times when that would be simpler.

Are you here to learn or slay the mythical dragon? Do you want to learn AD? If you don't believe in AD and it is that wrong, ignore it! You don't do this in the flat-earth society do you? Why us? Normally rage comes from fear. What is the fear people have of Carezani's work? That it could be correct? We teach a real science attitude of questioning the fundamentals, not tweaks upon tweaks to try and save a dying theory. That is what we teach.

Simple question. Are you here to learn about AD. Please don't answer "yes BUT".

Yes or no please. I will reject anything but a yes or no from you in name of this group and all who want to learn about AD and who actually read and study it. One word. If this is not acceptable to you then you may leave. Then, if you DO want to learn about AD, then come back and show that yo have read the article I gave you to read.

Thanks in advance.

And oh yes, of course we hate the billions spent at Cern and around the world on fruitless, useless things. And the public should know we waste this money so we can spend it on better things for the human race. Yes that is important to me - not wasting money. And believe me, that will be in my movie to help motivate the public to all this.

ONE WORD REPLY PLEASE!

-David

P.S. We're not worried about loosing people on this egroup. We're worried about learning and reading here and gaining critical thinkers who study and read before they hit "reply" in this instant information age.

So not knowing if he wanted me to answer his questions or answer yes/no I sent this in response, we'll just have to see what comes of it.

Would you prefer I quantify "most mind shattering levels of accuracy" or answer yes or no? It will be pretty difficult to do that or answer any of your other questions in just one word, especially if the choice is limited to yes or no. I can't even explain whether I read the link in yes or no.

So I think that will be the end of my membership of the AD community. It appears that AD is guilty of exactly the same faults that it claims exist in the real scientific community, lack of openness, unwillingness to debate etc. You will notice that at no point was my question actually answered, how do you explain that AD can't explain the motion of charged particles near the speed of light. Just like in the 6 years the board has been in existence they have not yet managed to explain what the velocity sum equation means, beyond "think more deeply", "buy the book" and "your thinking along the line of SR".

Is There A Doctor In The House?

So as a previous post elaborated I have been in discussion with the ADherents over on the Autodynamics discussion board, its been interesting, DaveDH seems pretty reasonable and is taking the time to explain things, as is someone called Travis, thanks guys. Its a load of nonsense, but at least I can see past all the contradictions to what the actual claims are now, faster than light particles, c not a constant etc etc. I think most people on the board are generally trying to be helpful, which is nice, one in particular though is a little, how shall we say?, unhinged.

Some of the classics from Dr. Lucy Hayes (not sure what she is a Dr of) to date include the following, enjoy.

On the past/future:

I am happy now because you are happy with the actual wrong paradigm.

Happily Carezani thought us that AD is Historically right now but will be historically wrong in the future regarding a new paradigm.

The only difference with SR and GR is that the next Paradigm will start following AD, differently to what happen with AD that not follow from SR-GR. Contrarily, AD jumped over SR and GR starting from Lorentz misconception and following Newton.

Unfortunately, in the future,100, 200 or 300 years from now will be many Mark supporting AD and rejecting the New Paradigm, historically right to be replace historically ........ in ...... the .... future........

Er what was going on there? Think she may have been drifting off at the end. But I think that she was claiming my offspring will one day be ADherents against the next theory. Not likely, whats the point of having kids if you can't brainwash them to hate the things you hate?

Thanks to ibaDaiRon for picking this one up, it was so difficult to read the whole thing it slipped by me.

Probably you have not clear ideas as happen with c, C and Cc because you never bought a book or read a Magazine in the Scientific Library, but of course, is needed know how to read.

This one is probably true, I was always averse to going to the library when I was an undergrad, it was always rammed with pashmina wearing girls called Jemima, or smelly rugby playing blokes called Dobbo or suchlike and they always took up all the desks despite only having 6 hours of lectures a week, get a job.
Right rant over back on track, so I think she is claiming I'm illiterate, but the irony is that its so badly written itself I can't be sure. I'm guessing English is not her native language, I mean I hope it isn't.

On reality:

I am so sorry, dear Mark, but AD is dedicated to Scientific Problems no to fantasies of **current science** regarding the Cosmos or the Einstein's GR fantasies, which have been proven wrong.

We cannot waste our time with those fantastic tales to sustain what Carezani, the Experiments and the observation show wrong.

She hasn't actually come up with any experiments that disprove SR/GR even when I pointed out that "Nobel prizes are worth real money you know".

Disaster

This is what ACS looks like on the ground...

Disaster, the main instrument on the Hubble Space Telescope died on Saturday. The camera, the Advanced Camera for Surveys (ACS) is the most in demand instrument on the telescope. The last call for proposals which only closed on Friday had 747 proposals to use HST, 498 (one of which was mine dammit) of which were to use ACS, thats 67% to you stat lovers. It looks like its not going to be possible to repair the instrument, at least not before the next servicing mission sometime next year, and even then there probably isn't enough time to do much while they are there. This is going to prove to be a huge loss to the astronomical community as no other instrument is capable of the fine resolution over a relatively large field of view that ACS provided. The servicing mission will install a new camera WFPC3, but this just won't be as sensitive as ACS at certain wavelengths (like the ones I'm interested in).

... and this is what it could do when in space.

It looks like we can kiss goodbye to our HST proposal, unless we can come up with a clever way to use one of the other instruments. Hmm, back to work.

Through The Looking Glass

Contact has been made, I'm now a fully signed up member of the Autodynamics Yahoo group. Fear not I haven't been assimilated, or turned to the dark side but it does provide an opportunity to ask some interesting questions. You can see my posts starting here, as you can see I haven't been very original with my screen name. As they already knew who I was, from this very blog, there didn't seem much point in trying to hide my identity. Should I turn up murdered, by a hail of electro-muons (WTF are they supposed to be anyway?), you'll know two things, that they were right after all and that what you don't believe in can still hurt you.

I have only had a few posts so far but have managed to discern certain features already. So far most of the people posting seem very keen to help, in sort of the creepy way you get with religious fanatics, you know what I mean, they offer you loads of free tea and biscuits, you sit there quietly nibbling on a rich tea but all the while you know they're eyeing up your soul, figuring out what it must be worth in the afterlife. Some of the responses are simply mistaken, some confused and some to put it mildly simply bat-shit mad, as in naked man running down the street claiming he can't get the spiders off mad, for example this one.

I have already learned several interesting "facts" about AD, like the fact that in AD E=mc^2 is believed to be true but c can change. So it applies differently to different objects, for electrons/protons c is the speed of light, but if they need to postulate (that's a fancy word for make up) a new particle that can travel faster than light, say the pico-graviton then c can actually be anything, like 27, 100 or the average IQ of and ADherent (50) divided by the number of times electro-muons detected in actual experiments (0) = infinity times the speed of light (Apologies just couldn't resist). Yes I know that's mental, but there you have it. To date I have had ignored the points where AD just doesn't work with what we know about the Universe, things like the existence of neutrinos, in favour of looking for inconsistencies in the theory itself, but I have learned that it isn't so much a theory as a bunch of ad hoc bolt ons, so if you disprove one they just stick another one on, like the non constancy of c as a speed limit. In future I think I may well bring in the selective way they apply their theory, any experiments they can match are good, any they cannot must be wrong etc.

So far its been fun, its forcing me to understand real Physics better, which is good (and useful in my line of work), but I think its also quite interesting to see the dynamics (no pun intended) of the group and how they respond to queries, so far mostly through constant exhortations to buy the book. Which of course I have no intention of doing.

A Short History Of The Dark Side - Part 3

The Hubble Ultra Deep Field, a view of the distant Universe, at a time before the influence of Dark Energy began to be felt, we think.

I think its time to finally round off the long running "Dark Side" trilogy, and like all final chapters it has to be bigger better and more exciting. So sorry but this one is pretty long.

When we left off we had been investigating the properties of the mysterious Dark Matter that permeates the Universe, despite being strange (only interacting through the force of gravity) DM is nevertheless a physical entity, in most theories some form of elementary particle. The next constituent of the Dark Universe is much weirder, being some strange form of energy which exerts a negative pressure on the Universe causing it to expand. Now I think many Astronomers are happy to admit that they are not happy about Dark Energy, everyone seems reasonably happy to admit the existence of Dark Matter, it simply turns up too often on too many scales, but the properties of Dark Energy at present are known from only one or two methods and even then not too accurately, making naturally cautious Astronomers worry about conclusions being drawn from them. Nevertheless the history and implications of a Dark Energy dominated Universe are interesting, so lets have a look at them.

Hubble's observation that essentially all galaxies are receding from us with a velocity that is proportional to the distance between the Milky Way and them was a vital discovery that provided the first evidence that the Universe was expanding. Naturally the idea of a finite age for the Universe (revolutionary at the time) intrigued people, what had happened in the past and what would happen in the future? For a long period of time the belief in the astronomical community was that the Universe started in a Big Bang and that over time the force of gravity would begin to counteract the expansion and slow it.


Hubble's original plot showing that distance to a galaxy and recessional velocity (or redshift) are related.

The mathematical formalism that determines the behaviour of the Universal Expansion shows that in this picture there are 3 possibilities for the fate of the Universe:

1. The Universe is not dense enough to halt the expansion and the Universe expands forever.
2. The Universe is exactly dense enough to overcome the expansion when the Universe reaches infinite size. It has the so called "critical density".
3. The Universe is more than dense enough to counteract the expansion and the Universe re-collapses.

Astronomers were therefore keen to determine which of these fates awaited the Universe. To do that they could make use of one of the best standard candles: Type 1a supernovae. In Type 1a supernovae a dense white dwarf that has been accreting matter from a companion suddenly passes over a limiting mass: the Chandrasekhar mass. At this mass the star becomes unstable, undergoes rapid runaway fusion and blows itself apart. Because the Chandrasekhar limit is so precisely defined it means that all Type 1a supernovae have almost exactly the same intrinsic brightness, they also have unique signatures in there spectra that mean they can be separated from other non-uniform SN, hence they can be used as standard candles. Put simply, one supernovae that is observed to be a quarter as bright as another must be twice as far away. To make this technique even more useful these things are bright, as in bright enough to be seen across billions of light years.

In the mid 1990's two groups were using these Type 1a supernovae as standard candles, in attempt to measure how much the expansion of the Universe had slowed since the Big Bang. To do this they combined the physical distance information from the supernovae with the redshift of the galaxy in which the supernovae occurred, this redshift through Hubble's law is also a distance but one that depends on the expansion of the Universe. Hence by plotting one against the other you get a plot of how the expansion of the Universe has changed over time, in essence you are looking for how Hubble's linear relation changes or curves over larger times/distances. When both groups plotted their results they both found the same puzzling result: instead of the rate of the expansion slowing over time it has actually been increasing. Damn it, I'm sure both teams thought as they contemplated all the extra work involved. But very rapidly it probably occurred to them that there's a Nobel prize in it for someone, hence a healthy dose of rivalry between the two teams.

You can see this in the top half of the figure above, which shows the results from the two surveys, what you see is the magnitude of the supernovae (a distance indicator) plotted against its redshift (a measure of the expansion of the Universe). The three lines show three predictions for the constituents of the Universe. Two dashes are for a Universe where the entire critical energy density is made up by mass (matter and dark matter), the three dashes are for a Universe where only 30% of the critical density exists in mass, and the solid line (which is best fit by the data) is for one where the Universe has the critical density, 30% being due to mass and 70% due to dark energy. New data on more and more supernovae at larger and larger distances has all agreed very well with the original results, meaning the Dark Energy has slowly become accepted as just another constituent of the Universe.

So what could be this strange Dark Energy? To date there are two main contenders, A cosmological constant and quintessence.

The cosmological constant can be thought of as a pressure of a vacuum, particle physics in fact predicts that empty space should have vacuum fluctuations that provide exactly the type of negative pressure required, unfortunately the predictions from particle physics for the level of this pressure are out by up to 120 orders of magnitude, often called the most incorrect prediction in history, oops. The problem is how to cancel out most of this pressure but not all of it, to date no one is sure how to do this. The implications of a cosmological constant are that the expansion will necessarily increase without end, as space is what is causing the expansion the more space there is the more expansion there is. Eventually all structures not gravitationally bound will be separated by so much space light will never be able to pass between them, turning the Universe Dark. In other words in a Milky Way in the distant future, all of the galaxies beyond out local group will slip beyond this distance and disappear forever. Not a very cheerful thought, but hey, who said existence had to be cheerful?

Quintessence is thought to be some sort of particle-like excitation with a possibly dynamical nature. In other words it need not be a constant value per area of space as the cosmological constant, it could vary in strength over time and possibly have different strengths in different areas of the Universe. This is similar to the behaviour of the field that is thought to have caused the intense period of expansion in the early Universe known as inflation. Quintessence could even reverse and cause a contraction of the Universe at some point.

So where does that leave us? What is the eventual fate of the Universe? The truth is that we really don't know for sure, our theoretical knowledge of what is causing the accelerating expansion is not good enough to allow us to determine with certainty what the Universe in the very distant future will be like. The best we can do at present is to try to determine if either of the two cases above can be ruled out. The trick to determining which of these two cases is correct (if either is) is to extend the observations of Type 1a SN to higher redshift and track how the speed of expansion changes. There are many studies ongoing to try to do this to higher and higher precision, expect more interesting results in the coming years.

More Gravity Fun - Update

So it looks like the good people over at the Autodynamics discussion group have decided to answer my queries (specifically this one) in the most emphatic way possible; by totally ignoring it. They have posted a response to a previous question without allowing my message to be published. Now maybe this is because they are trying to come up with a solution, but that really shouldn't matter, they should be open about the issues raised and see if any of the other 165 members of the board can come up with a solution.

I'm going to repost the message tomorrow, if it is blocked again I'm going to have to put this down to yet more hypocrisy on their part, after all they are always claiming mainstream science ignores or suppresses alternative views.

Britain On The Web

Whilst searching for pictures for my previous post I came across this little gem: geograph. The aim of the site is simple, to collect at least one photograph of the main geographical features of every 1km x 1km grid square in the UK ordinance survey maps. So far they have over 300,000 images covering almost 150,000 square km of the UK (or about 62% of the surface area of the UK). Whats cool about the site is that you can search by postcode/placename, or by clickable map and find any photograph taken within that area.

As you would expect most photographs in a given area tend to focus on the same areas, so the grid square for Durham City is of course dominated by pictures of the castle and cathedral. However there is also an attempt to show the real use of areas as well, so the Durham grid square has pictures of the annual miner parade, London has views of gridlocked cars etc.

The question now is whether or not Google already offers this, and if not how long until it does.

New Links.

I'm planning on periodically adding to the links section on the sidebar to the right, I'm not sure how often this will be, it all depends on how much work I have on. Anyway, here is the first set of new links, all to do with pictures of Science:

The Hubble Heritage site has a very good selection of some of the HST's greatest hits, many will be familiar but there are one or two new ones, and others that have changed slightly since they were first released. See them in all their glory here.

In a similar vein, but looking the other way, here is a link to the US Geological Survey's image gallery, check out the galleries called Earth As Art.

The Earth Science Picture of the Day, is set up along much the same lines as the Astro-Picture of the Day, in particular check out the archives for many spectacular pictures of the Earth and natural phenomena.

The National Geographic also has a picture of the day, the archive found here is again worth a look (its where the picture at the top comes from).