Physics Discussion Thread

Drevin · Post by **Drevin** » 11 Aug 2009 21:39

Sanjay M · Post by **Sanjay M** » 12 Aug 2009 01:14

And it uses the Wii!

Meanwhile, NASA's Kepler probe is scanning the heavens, and Bad Astronomy's Phil Plait describes what's happening:

http://blogs.discovermagazine.com/badas ... ler-works/

India should send up its own version of a Kepler type of stargazing telescope, to do planet-finding.

Sanjay M · Post by **Sanjay M** » 13 Aug 2009 02:23

If we're going to figure out a way to travel FTL, it'll have to be by uncovering the structure of spacetime, which is what currently limits things to under lightspeed. There are various competing theories on how everything fits together, trying to connect Einstein's large-scale Relativity with the small scale of quantum behavior. So far, mankind lacks the kind of energy necessary to produce the extreme conditions that can uncover the hidden nature of spacetime, but there are powerful astronomical events occurring from time to time, which maybe able to shed some light on this.

Here's a good article on the powerful new detectors like MAGIC, HESS, MACE, and IceCube, which will help to uncover the structure of spacetime itself:

http://www.newscientist.com/article/mg2 ... de-of.html

A further gamma-ray telescope, the Major Atmospheric Cherenkov Telescope Experiment (MACE), 4500 metres up on the Tibetan plateau in the remote region of Ladakh, India, will open that observational window still further. When completed in 2011, MACE will be the highest-altitude gamma-ray telescope in the world, capable of observing gamma rays with a wide range of energies. "Then we will have another observatory 5 to 6 hours in front of MAGIC," says Wagner. "That could lead the way to a continuous, 24-hour observation of certain objects."

There are some amazing discoveries waiting to happen at these powerful detector sites placed at various locations around the world.

ISRO will also soon be launching Astrosat, which is a gamma-ray and x-ray detection probe capable of monitoring some of these high-energy emissions from space.

http://en.wikipedia.org/wiki/Astrosat

If science can come up with a detailed model of how spacetime works, then it may potentially open the way for engineers to develop means to modify or exploit the nature of spacetime for achieving FTL travel.

nikhil_p · Post by **nikhil_p** » 20 Aug 2009 02:41

I have done my BSc something like 5 years ago. Want to do my MSc but cannot as it is a full time course and I cant afford to leave my job...can someone please help with some information!
Physics is my first love...

negi · Post by **negi** » 20 Aug 2009 03:24

^ If you do not have any responsibility (dependents ,parents,wife or kid) then imho you should follow your heart and pursue a full time Msc or even an integrated Phd. I am unaware of career prospects in India in pure sciences after a correspondence course . After the 6th pay commission implementation the R&D and govt sector have become attractive avenues and there is pretty serious competition to get into relevant organizations and even academic institutions.

Ofcourse IIT's ,IISc and Jadhavpur Uty are the right institutes for Physics in India however if you wish to go abroad and money is an issue German Universities are pretty good ,cheap and yet qualitatively right up there (at least top German state universities) , however proficiency in German language is required .

Btw I have always wondered for pursuing masters while rest of the world uses a generic GRE exam , our institutes go by GATE scores which is pretty technical exam specially if one wishes to pursue Masters after a gap of several years.

paging folks in academics/science for more details/clarification.

Amber G. · Post by **Amber G.** » 21 Aug 2009 11:24

Also Online courses such as from MIT (physics as well as other subjects) are pretty nice.
http://ocw.mit.edu/OcwWeb/web/home/home/index.htm

(BTW Physics 8.01 has been one of the most popular course

.

(Also check out Feynman's materials - check my post on last page)
http://research.microsoft.com/apps/tool ... index.html

nikhil_p · Post by **nikhil_p** » 22 Aug 2009 00:13

Amber G. wrote:Also Online courses such as from MIT (physics as well as other subjects) are pretty nice.
http://ocw.mit.edu/OcwWeb/web/home/home/index.htm

(BTW Physics 8.01 has been one of the most popular course .

(Also check out Feynman's materials - check my post on last page)
http://research.microsoft.com/apps/tool ... index.html

Thanks...this is wonderful.

negi wrote:^ If you do not have any responsibility (dependents ,parents,wife or kid) then imho you should follow your heart and pursue a full time Msc or even an integrated Phd. I am unaware of career prospects in India in pure sciences after a correspondence course . After the 6th pay commission implementation the R&D and govt sector have become attractive avenues and there is pretty serious competition to get into relevant organizations and even academic institutions.

Ofcourse IIT's ,IISc and Jadhavpur Uty are the right institutes for Physics in India however if you wish to go abroad and money is an issue German Universities are pretty good ,cheap and yet qualitatively right up there (at least top German state universities) , however proficiency in German language is required .

Btw I have always wondered for pursuing masters while rest of the world uses a generic GRE exam , our institutes go by GATE scores which is pretty technical exam specially if one wishes to pursue Masters after a gap of several years.

paging folks in academics/science for more details/clarification.

I have the responsibilities

Plan to get a large bank balance and then pursue my dreams...

Rahul M · Post by **Rahul M** » 22 Aug 2009 00:20

nikhil do you want to just complete a masters or pursue physics as a career ?

nikhil_p · Post by **nikhil_p** » 22 Aug 2009 00:46

First complete my masters...then get into research...so i guess 'yes' to both questions.

negi · Post by **negi** » 22 Aug 2009 02:22

Rahul fwiw...please do post relevant info on this thread for everyone's benefit.

samuel · Post by **samuel** » 25 Aug 2009 08:36

nikhil_p wrote:I have done my BSc something like 5 years ago. Want to do my MSc but cannot as it is a full time course and I cant afford to leave my job...can someone please help with some information!
Physics is my first love...

Nikhil,
Physics is a wonderful subject and along with applied math it makes for potent preparation.
After some point in your research career or training, you will realize that there is really no such a thing as physics or computer science or math...everything merges into a holistic view of knowledge where there are puzzles and skills to master and a mind to exercise. You will see connections between pieces that appear quite far apart. Genes and chaotic dynamics, fluids and lie algebra, origami and graph theory. So, generally speaking the best approach is to pursue the thing you love with most love because that opens it all up the best.

You don't have to go to MIT to understand physics, in fact most students I meet are duds in the sense that it is all point a to point b for them. If you are in love, pick up a thin, paper-back book, and devour it. Ask one question that really intrigues and take it from there. You can do this in your spare time.

Best,
S

nikhil_p · Post by **nikhil_p** » 25 Aug 2009 19:54

samuel wrote:
nikhil_p wrote:I have done my BSc something like 5 years ago. Want to do my MSc but cannot as it is a full time course and I cant afford to leave my job...can someone please help with some information!
Physics is my first love...
Nikhil,
Physics is a wonderful subject and along with applied math it makes for potent preparation.
After some point in your research career or training, you will realize that there is really no such a thing as physics or computer science or math...everything merges into a holistic view of knowledge where there are puzzles and skills to master and a mind to exercise. You will see connections between pieces that appear quite far apart. Genes and chaotic dynamics, fluids and lie algebra, origami and graph theory. So, generally speaking the best approach is to pursue the thing you love with most love because that opens it all up the best.

You don't have to go to MIT to understand physics, in fact most students I meet are duds in the sense that it is all point a to point b for them. If you are in love, pick up a thin, paper-back book, and devour it. Ask one question that really intrigues and take it from there. You can do this in your spare time.

Best,
S

I agree to what you say...however I want to make a profession out of it as well and so I need a pg degree at the very least. I would not be able to work on the CERN collider or even at the GMRT or IUCCA or wherever unless I have a PG degree sheet under my arm...
I have a lot of theories which I work on in my spare time. That keeps me busy

Sanjay M · Post by **Sanjay M** » 30 Aug 2009 18:11

A single molecule, pentacene, has been visually imaged in unprecedented detail:

http://news.bbc.co.uk/2/hi/science/nature/8225491.stm

Here is the same molecule represented in a classical diagram:

You can see that the delocalized pi electrons actually spend most of their time on the outer ends of the molecule, in contrast to what the classical diagram implies.

Neshant · Post by **Neshant** » 30 Aug 2009 20:03

I have done my BSc something like 5 years ago. Want to do my MSc but cannot as it is a full time course and I cant afford to leave my job...can someone please help with some information!
Physics is my first love...

i'm in the same predicament but not with physics but rather with mathematics.

I wish i had taken more math in university. I find that i apply the little math i do know to solve quite a number of engineering problems daily. I can only guess how much more creative i could be if i knew more math.

Sanjay M · Post by **Sanjay M** » 12 Sep 2009 06:23

QuantumElectroDynamics by Feynmann:

Sanjay M · Post by **Sanjay M** » 13 Sep 2009 01:52

Scientists Describe Gravitational 'Tubes' to Reduce Propulsion Requirements

http://www.telegraph.co.uk/science/spac ... cient.html

So these are then useful transit corridors to facilitate movement, even though they're not necessarily fast. And of course since the planetary positions are always changing because of their orbital motions, the corridors are shifting around over time.

I think the challenge is to develop a model that would allow prediction and identification of useful corridors and when they would appear, in order to best facilitate space missions.

Sanjay M · Post by **Sanjay M** » 18 Sep 2009 10:58

Here's an interesting article about a new breakthrough in the manufacture of a superconducting radio-frequency cavity:

http://nextbigfuture.com/2009/09/superc ... avity.html

If this new cavity were tested for EMdrive purposes, could it reveal a new mechanism for propulsion? (the implication being propulsion without onboard propellant mass)

Sanjay M · Post by **Sanjay M** » 29 Sep 2009 08:59

So far the Top Quark has been produced in pairs, but now unambiguous evidence has been shown of single Top Quarks being produced by themselves - at a significance level of 5 standard deviations!

http://arxiv.org/ftp/arxiv/papers/0909/0909.4518.pdf

That's evidence of some new physics - perhaps even Higgs Boson.

Bade · Post by **Bade** » 30 Sep 2009 00:13

Production of single tops are not necessarily any sign of the existence of the Higgs Boson.

More details on why the decay product will be in pairs if to be found. The chances are higher since the branching fraction is higher.

More on Higgs decays.

Bade · Post by **Bade** » 06 Oct 2009 23:03

A great opportunity for Indian science

Calling young hands on board.

Rahul M · Post by **Rahul M** » 06 Oct 2009 23:40

a comment from ^^^

Will the good professor explain what "major discoveries" this behemoth will make? Actually, forget the plural and name a single discovery that this instrument is likely to make. This is an idea that is very late in the day, as is typical of Indian projects. Worldwide, INO will have to compete with large experiments like Double Chooz, Nova, Daya Bay, K2K, LBNE at DUSEL etc. What assurance does the Indian public have that such a Mega-Wastage has any chance of producing any discovery at all?
from: Abdul Okullah
Posted on: Sep 26, 2009 at 12:15 IST

perhaps we know this author ?

and a reply

At the outset, let me congratulate Prof. Rajasekaran for a wonderfully written article. I would like to address two issues. First, the question of environmental and ecological disturbance and second the question of "what major discoveries?" Regarding the former, the problem only pertains to the period of construction which will be at most 2-3 years. Once the cavern is built and the magnetized iron detector is in place, the traffic along the road to Masinagudi, the proposed site in the Nilgiris, will reduce to a trickle and will constitute little threat to the elephants or tigers. The INO collaboration, after intense study, has made a detailed environment and habitat sensitive plan of how the traffic is to be managed during the construction phase, i.e. how many truck trips per day etc, for taking in the construction material as well as the iron and taking out the debris. Experts in the environment ministries of both the Central and the State governments are involved in this and will ensure that all safety and sensitivity norms are adhered to. It should be pointed out that the State Government had earlier constructed a hydel power station there (adjacent to the proposed cavern) and has experience in transporting construction material to Masanagudi. Coming to the question of discoveries, there is a major yet-to-be achieved goal in the neutrino sector, namely the resolution of the octant ambiguity (i.e. whether the atmospheric neutrino mixing angle is less or greater that 45 degrees) that Double Chooz, Nova, Daya Bay, T2K and DUSEL will have problems finding. This is because all these detectors work wih baselines less that a thousand kilometers. ICAL (the magnetized calorimeter for INO and detecting atmospheric neutrinos) has the unique advantage of having the larger part of the earth with baselines of then order of many thousands of kilometers and can beat all of them in determining this unknown fundamental fact. Furthermore, once an intense muon neutrino beam (from a European neutrino factory) or beta beams from CERN, Geneva, are directed at INO, ICAL will have the unique advantage of sitting at the 'magic baseline' length of about 7500 kms where many media effects disappear and it may be possible to test whether neutrinos violate the CP symmetry, a fact crucial to the understanding of the genesis of the present matter (and not anti-matter) dominated universe. Finally, INO will not just be ICAL. Many other experiments will be done there.
from: Probir Roy
Posted on: Sep 29, 2009 at 11:54 IST

I guess the reply is from Prof Probir Roy of TIFR.

Bade · Post by **Bade** » 07 Oct 2009 01:01

The last comment is from prof roy from tifr for sure. Quite to the point.

Javee · Post by **Javee** » 07 Oct 2009 06:31

Water in Moon- Chandrayan's picture:

http://zuserver2.star.ucl.ac.uk/~idh/apod/ap090928.html
Water has been discovered on the surface of the Moon. No lakes have been found, but rather NASA's Moon Mineralogy Mapper aboard India's new Chandrayaan-1 lunar orbiter radios back that parts of the Moon's surface absorb a very specific colour of light identified previously only with water. Currently, scientists are trying to fit this with other facts about the Moon to figure out how much water is there, and even what form this water takes. Unfortunately, even the dampest scenarios leave our moon dryer than the driest of Earth's deserts. A fascinating clue being debated is whether the water signal rises and falls during a single lunar day. If true, the signal might be explainable by hydrogen flowing out from the Sun and interacting with oxygen in the lunar soil. This could leave an extremely thin monolayer of water, perhaps only a few molecules thick. Some of the resulting water might subsequently evaporate away in bright sunlight. Pictured above, the area near a crater on the far side of the Moon shows a relatively high abundance of water-carrying minerals in false-colour blue. Next week, the new LCROSS satellite will release an impactor that will strike a permanently shadowed crater near the lunar south pole to see if any hidden water or ice sprays free there.

Peek in to the center of Milky way:
http://astrosurf.com/sguisard/Pagim/GC.html
This image is a 1 billion pixel RVB mosaic of the galactic center region (340 millions pixels in each R,V and B color). It shows the region spanning from Sagittarius (with the Milky Way center and M8/M20 area on the left) to Scorpius (with colorful Antares and Rho Ophiuchus region on the right) and cat paw nebula (red nebula at the bottom). This mosaic was assembled from 52 different sky fields made from 1200 individual images and 200 hours total exposure time, final image size is 24000x14000 pixels. The images were taken with a SBIG STL camera + Takahashi FSQ106Ed f/3.6 telescope and NJP160 mount from the clear skies of ESO Paranal Observatory in Chile. This mosaic is one of the three parts of the ESO Gigagalaxy Zoom project together with this incredible whole sky mosaic image by ESO/S.Brunier and this fantastic ESO mosaic image of the Lagoon nebula region.

negi · Post by **negi** » 07 Oct 2009 21:16

Dr. Venkatraman Ramakrishnan has won the Nobel prize for Chemistry .

from TOI

57-year-old Ramakrishnan, born in the temple town of Chidambaram in Tamil Nadu, is the seventh Indian or of Indian origin to win the prestigious award.

Born in 1952, Ramakrishnan earned his B.Sc. in Physics (1971) from Baroda University in Gujarat and later migrated to the US to continue his studies where he later got settled and attained US citizenship.

He earned his Ph.D in Physics from Ohio University in the US and later worked as a graduate student at the University of California from 1976-78.

During his stint at the varsity, Ramakrishnan conducted a research with Dr Mauricio Montal, a membrane biochemist and later designed his own 2-year transition from physics to biology.

As a postdoctoral fellow at Yale University, he worked on a neutron-scattering map of the small ribosomal subunit of E Coli. He has been studying ribosome structure ever since.

Ramakrishnan, now a senior scientist at the MRC Laboratory of Molecular Biology in Cambridge has authored several important papers in academic journals.

In the August 26, 2000 issue of Nature, Ramakrishnan and his co-workers published the structure of the small ribosomal subunit of Thermus thermophilus, a heat-stable bacterium related to one found in the Yellowstone hot springs.

With this 5.5 Angstrom-resolution structure, Ramakrishnan's group identified key portions of the RNA and, using previously determined structures, positioned seven of the subunit's proteins.

In the September 21, 2000 issue of Nature, Ramakrishnan published two papers. In the first of these, he presented the 3 Angstrom structure of the 30S ribosomal subunit.

His second paper revealed the structures of the 30S subunit in complex with three antibiotics that target different regions of the subunit. In this paper, Ramakrishnan discussed the structural basis for the action of each of these drugs.

After his postdoctoral fellowship, Ramakrishnan joined the staff of Brookhaven National Laboratory in ther US. There, he began his collaboration with Stephen White to clone the genes for several ribosomal proteins and determine their three-dimensional structures.

He was also awarded a Guggenheim fellowship during his tenure there, and he used it to make the transition to X-ray crystallography.

This is humbling.

Amber G. · Post by **Amber G.** » 08 Oct 2009 03:31

Congrats!

Sanjay M · Post by **Sanjay M** » 09 Oct 2009 09:55

Move over Heim and Mach-Lorentz thrusters - there's a new propulsion system in town:

http://www.technologyreview.com/blog/arxiv/24211/

Meet Hilbert's Hypervelocity thruster, now resurrected by Frank Felber.

Hey, and it gives the Large Hadron Collider a new use. Even if it doesn't discover the Higgs Boson first, perhaps it could redeem itself by discovering a new mechanism of propulsion.

The Eurocrats will love it!

Sanjay M · Post by **Sanjay M** » 11 Oct 2009 23:59

It's just a Popsci article, but it too talks about Hilbert's Hypervelocity Drive:

http://www.popsci.com/technology/articl ... ell-theory

It sounds like something far-out and sci-fi, but it may be based on sound physics.

vina · Post by **vina** » 13 Oct 2009 07:31

Sanjay M wrote:Move over Heim and Mach-Lorentz thrusters - there's a new propulsion system in town:

http://www.technologyreview.com/blog/arxiv/24211/

Meet Hilbert's Hypervelocity thruster, now resurrected by Frank Felber.

Hey, and it gives the Large Hadron Collider a new use. Even if it doesn't discover the Higgs Boson first, perhaps it could redeem itself by discovering a new mechanism of propulsion.

The Eurocrats will love it!

Well, it looks like Bade Saar and Fizzyicysts of his ilk have been watching too many Terminator (1,2,3) kind of movies.

It must be our prediction that all Higgs producing machines shall have bad luck,” Dr. Nielsen said in an e-mail message. In an unpublished essay, Dr. Nielson said of the theory, “Well, one could even almost say that we have a model for God.” It is their guess, he went on, “that He rather hates Higgs particles, and attempts to avoid them.”

This malign influence from the future, they argue, could explain why the United States Superconducting Supercollider, also designed to find the Higgs, was canceled in 1993 after billions of dollars had already been spent, an event so unlikely that Dr. Nielsen calls it an “anti-miracle.”

..

Hmm. Bade Saar as the muscle bound Scharznagger Look alike out to save the world ? . Nice thought eh ?

Sanjay M · Post by **Sanjay M** » 12 Nov 2009 06:42

Stars which host planets are found to have much lower lithium content:

http://www.wired.com/wiredscience/2009/ ... t-hunters/

karthik · Post by **karthik** » 13 Nov 2009 22:37

Hello, I was wondering if our everyday micro wave oven works in the same principle of an Radar? Do all those materials that do not get heated or reflect micro wave can be taken as radar absorbent materials? I know its very basic but just curious.

Amber G. · Post by **Amber G.** » 17 Nov 2009 01:52

^^^^Hello Karthik yes. - Micowave heats up water (or polarized molecules) ( that's why some call it dielectric heating) .. the RF waves have approx same frequency as radar and in fact microwave heating was discovered as a byproduct of wartime radar .. (story goes one person (who was using magnetron ) had his chocolate melted in his pocket or something like that) ( (I even heard that one early (1950's? or 60's) microwave oven (produced by Raytheon) was called radarange..

(BTW, it might be typo on your part but - radar absorbent materials (by definition) absorb radar and thus will get hot, the reflecting materials bounces the energy back while transparent ones will let the waves through .

Bade · Post by **Bade** » 17 Nov 2009 02:19

I've heard the same story about the use of microwaves for heating. Wonder with the chocolate how much of the body could have got cooked too.

More than reflection, it can be emission after absorption. For instance, microwave sounding instruments are used in remote sensing. Or one can have passive instruments where one records the emission from a large water body illuminated with solar radiance.

Amber G. · Post by **Amber G.** » 21 Nov 2009 22:23

LHC starts again:
Beam Circulating in LHC Again!

Amber G. · Post by **Amber G.** » 10 Dec 2009 02:12

x post from other thread:
Noble prize winner "autographing the back of chair"

If you want to see the Noble lecture - " Decoding the Genetic Message" by Venkatraman Ramakrishnan

check out:http://nobelprize.org/mediaplayer/index.php?id=1208

Sanjay M · Post by **Sanjay M** » 17 Dec 2009 05:14

Earth-sized Watery World Found Orbiting Nearby Star

SaiK · Post by **SaiK** » 17 Dec 2009 19:11

only about 40 light-years away... [40 Light Years = 235145014927344.28 Miles]

q: what would be the fastest space craft that we can make that sling shot to this place at quickest possible time?

Amber G. · Post by **Amber G.** » 17 Dec 2009 23:08

^^^ That, of course, is 40 years (one way)

(Also BTW having 16 sig. figures there is sort of meaning less

- also 40.0000 light years translates to 2.35140 x 10^14 (and not 235145 ...)

SaiK · Post by **SaiK** » 18 Dec 2009 04:46

that would be google's fault.

Sanjay M · Post by **Sanjay M** » 19 Dec 2009 07:37

ISRO to Search for Exo-Planets

This is a superb idea. Our ancestors used to scrutinize the stars, and now our current and future generations will search for and study objects orbiting those stars.

Sanjay M · Post by **Sanjay M** » 25 Dec 2009 22:10

Scientists Say Alien Moons More Likely to Bear Life Than Planets

Hmm, so if you had a bunch of fertile moons orbiting a single large planet, then you could have a civilization emerging on at least one of them, and then spreading to the other adjacent moons to become a civilizational cluster.

What an interesting idea!

I can imagine this leading to an India-like situation, where you had these multiple feuding moons, which while being distinct from each other, nevertheless had more in common by being part of a common cluster.

This gives me a science fiction story idea...