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0
votes
1answer
25 views

Sloan Digital Sky Survey (SDSS) spec file headers

I downloaded spectra from Sloan Digital Sky Survey (SDSS), which has the following column headers flux, loglam, ivar, and_mask, or_mask, wdisp, sky and model (...
4
votes
2answers
58 views

Combining two data points with different uncertainties

I have two separate algorithms (call them "A1" and "A2") which reconstruct the $(x, y)$-position of an event in a particle detector. I can test both of these algorithms on simulated events from a very ...
16
votes
2answers
893 views

How to deal with zero uncertainties?

Suppose you measure quantity $x$ with an uncertainty ${\rm d}x$. Quantity $f$ is related to $x$ by $f=x^2$ . By error propagation the uncertainty on $f$ would be ${\rm d}f=2x{\rm d}x$. If a certain ...
1
vote
1answer
33 views

Gamma Ray Burst data

I wanted to know if there was some database for gamma ray burst (GRB) data. I would like to get the luminosity and duration of recorded GRBs. So far, I have come across this website, but since I do ...
2
votes
1answer
33 views

How would you read memristor data?

According to many experts; memristors have the potential to change and drastically improve data storage and processing power of computers. But there is one small thing that doesn't fully make sense to ...
1
vote
0answers
50 views

Current length of the solar day?

As can be seen in this diagram, the length of the solar day has varied Question considerably the last century. But the diagram is incomplete and doesn't show the very last years. Can anyone tell me ...
0
votes
0answers
38 views

Inconsistencies in data: magnetic field in solenoid

In lab for our Calculus based Electricity and Magnetism course we are, for one portion of our lab, exploring the relationship between increasing the number of loops in a solenoid and the magnetic ...
0
votes
0answers
42 views

How many atoms do we need to store a bit?

And which kind of storage (HDD, flash, blue-ray, etc) has the most efficient atoms/bit ratio?
1
vote
0answers
24 views

Data acquisition from Pins ( 5Volt) [closed]

I'm trying to creat a data acquisition system using: computer Geosig ve-53 KPci3101 from the seismic sensor's manual we can see that every pin's output is a 5 volt (or 10?), my question is, how ...
15
votes
3answers
4k views

Can gravitational wave be used for data transmission?

Imagine an advanced civilization which can manipulate gravity like we manipulate electromagnetic radiation. Could they already be using gravitational waves for data transmission across different ...
3
votes
0answers
51 views

Data storage in flash drives

In a pen drive, I have read that data is stored by trapping the electrical signals sent from the computer in silicon dioxide chambers. But what I dont understand is that how does the electrical signal ...
0
votes
0answers
16 views

Data: decoherence time

Searching for experimental data on decoherence time. For example, this type of data can look like (but is not limited to): atomic species (eg. Carbon) vs. decoherence time. Physics stackexchange ...
0
votes
0answers
23 views

Data arrival from another observable universe [duplicate]

If we received data transmitted from far, far away e.g. 250 million light years, could it convey information regarding the then past state of the observable universe from the perspective of that ...
4
votes
3answers
73 views

Raw data acquirable from amateur astrophotography

What raw data can I possibly acquire from an 8" Classical Dobsonian Telescope, and a DSLR? Could anything eye-opening to amateur astronomers be computed or calculated first-hand with such equipment? I'...
1
vote
3answers
556 views

Why we don't use gamma rays, x-rays or ultraviolet to transmit data?

The greater the frequency range of a transmission medium, the greater the number of bits per second it can transmit. In other words, the bigger the bandwidth in hertz available, the bigger the ...
0
votes
1answer
56 views

NED vs. SIMBAD: Which is more accurate?

I'm doing some research on M33. NED lists the luminosity as 6.27. SIMBAD gives it as 5.27. First, it looks odd to me that the difference is exactly 1. Second, I've seen other differences comparing ...
1
vote
1answer
44 views

Reading ensdf files

I understand that this is more of a computing question, but I still think the appropriate place to ask it is here. The Evaluated Nuclear Structure Data Files are on the internet, available for ...
1
vote
1answer
124 views

SDSS spectra FITS format: what do the rows mean?

This might be in the FITS Header, but I couldn't find it. I am looking at the FITS files for SDSS 1D spectro images from DR7 using the SDSS Data Archive Server at das.sdss.org (there might be an ...
3
votes
1answer
83 views

Effects of magnets on memory cards

I have always believed in keeping magnets and data storage devices far away from each other. Friends say I'm excessively cautious about it, but I seem to have a lot less data loss than they do! As ...
-1
votes
1answer
210 views

Did we get near Pluto with our current technology? [closed]

I was sent from Skeptic to here. We all know that NASA has successfully carried out the mission for getting near Pluto. More here. It is very difficult for me to accept that we already have the ...
0
votes
2answers
98 views

How to find time when temperature crossed certain threshold?

I have a data from experimental system concerning temperature of molten lead. In this system, temperature is increased in one place and then is measured when this increase of temperature travels to a ...
0
votes
3answers
93 views

Database of experimental cross sections for atomic collisions

Does the atomic-physics community keep a comprehensive database of experimental data (cross sections) for atomic collisions? I am looking for data about Bremsstrahlung, ionization, elastic and ...
15
votes
1answer
431 views

Does my green laser pointer emit three distinct frequencies, or is my measurement flawed?

I was playing around with a cheap diffraction grating and my set of laser pointers, and I noticed that while the red and the blue pointers produce a single point in the spectrum, my green laser ...
1
vote
1answer
100 views

Quantum anharmonic ocscillator $E_0(\lambda)$ curve or table

I am looking for the exact data on $E_0(\lambda)$ for the anharmonicity $\lambda x^4$. The perturbative expansion is the following: $E_0(\lambda)\approx 0.5(1+1.5\lambda -5.25\lambda ^2+41.625\lambda^...
0
votes
1answer
78 views

Can Black Holes Maintain Data Entropy When Formed By a Data Storage System?

It's been shown that black holes don't destroy information. There's a little-known scenario in computer science (Specifically AI) where an advanced civilization creates an artificial intelligence that ...
3
votes
1answer
174 views

What does 'channel' mean?

I see many plots like the following that graph counts per channel, I know what a 'count' is, but I don't know what a 'channel' is. Could somebody please explain to me? My guess is that it is that ...
0
votes
1answer
39 views

What does a goniometer (sound) show?

In looking into 2D representations of audio, I came across a tool called a goniometer. I'm aware that a goniometer refers also to a device for measuring angles, but in this context it refers to one ...
0
votes
1answer
43 views

Data processing Data [closed]

Is there anything in the world that data, processes the data? I meant that instead of full utilization of CPU, is there any data or program that handles data/logic processing?
-1
votes
1answer
87 views

Energy stored in hard disk [closed]

What is the type of energy stored in hard disk when data is stored? And Can we use it for electric power production?
1
vote
5answers
486 views

Why is microwave better than visible light for point to point data communication?

In the electromagnetic spectrum, it appears that the shorter the wave length, the better the bandwidth due to higher frequency. Some communication systems utilize microwave to transmit data to offer ...
0
votes
0answers
45 views

Create a transmission protocol to transfer both data and energy(Wireless Communication)

Is there a protocol by which we can design systems that jointly transfer both data and energy ? Some kind of gadget that collects the received energy, temporarily stores it in a battery and later uses ...
1
vote
2answers
965 views

Sellmeier Refractive Index of Standard Air

The question: What is the Sellmeier description of the refractive index of air at some reasonable temperature, pressure, and water content? The description must be in the following form:$$ n^2(\...
0
votes
0answers
48 views

Milky Way Density Profile

Does anyone know where I can find either a printed version or, better, a downloadable dump of data giving me the density profile of the Milky Way? I'm looking to put together a quick-and-dirty ...
0
votes
0answers
83 views

Is there a machine readable format of the data tables in Particle Data Group PDFs?

Is there a machine-readable format of the tables of data in PDG documents such as this one? http://pdg.lbl.gov/2011/download/rpp-2010-booklet.pdf Something such as JSON, XML, CSV, HTML, or anything ...
28
votes
8answers
10k views

Since cables carry electricity moving at the speed of light, why aren't computer networks much faster?

Why can't cables used for computer networking transfer data really fast, say at the speed of light? I ask this because electricity travels at the speed of light. Take Ethernet cables for example, I ...
0
votes
1answer
36 views

Nuclear Compton Scattering Data

Is there a repository where one can find unpolarized nuclear Compton scattering data $\gamma (Z,N)\rightarrow \gamma (Z,N)$ for specific nuclei $(Z,N)$? or even some parametrization of structure ...
4
votes
2answers
357 views

Computer parsable table of nuclides

I am looking for an computer parsable (CSV, XML, JSON, since I didn't find anything, I am happy with almost everything) file (or collection of files) that contains the information you can find in a ...
1
vote
1answer
68 views

What is the correct way to handle significant figures when calculating compound uncertainties? [duplicate]

When processing experimental data, and calculating an uncertainty value in multiple steps, should intermediary uncertainties be used to a certain number of significant figures or kept to the full ...
0
votes
2answers
492 views

List of experimental band gap

does anyone know where one can find a list, database, book of experimental bandgap values of semiconductors? Is there such a collection? Or do I need to scour papers one at a time to get the values?
2
votes
3answers
417 views

Measurements for thermal diffusivity of graphene?

We have known for a long time that graphene has in-plane thermal conductivity ranging between 2000 and 4000 $W m^{-1} K^{-1}$. But in order to model heat transport on a sheet of graphene, we need more ...
0
votes
2answers
355 views

Debye temperature for the steel?

I'm looking for data on Debye temperature of steel (ideally with a known carbon concentration, structure, and set of phases), but find only data on elements. Do You happen to meet the data in papers, ...
2
votes
0answers
84 views

Where can I get latest full updated list of supernovae candidates from the SDSS-II Supernova Survey?

I am doing a project where I need the list of supernovae candidates from the Sloan Digital Sky Survey II (SDSS-II) supernova survey. One list is available as part of the data-release-7 (DR7) website. ...
1
vote
1answer
55 views

Does speed of writing data on an optical disk affect the speed of reading data? [closed]

Does speed of writing data on an optical disk ( like DVD ) affect the speed of reading data from that disk ? even a little?
1
vote
2answers
424 views

Is there a star catalog for download?

Is there a downloadable star catalog which not only includes positions, but also spectral class, size, etc.? A CSV file would be great for the sake of easiness.
12
votes
1answer
323 views

Statistical analysis of data in Physics

Analysis of data is integral in bridging the gap between theory and experiment. How much do the results of the analysis depend upon the choice between Bayesian and frequentist methods? For instance, ...
1
vote
1answer
96 views

Transmutation with cosmic radiation possible?

Can cosmic radiation (alpha radiation) transmute the material of a space craft, particular carbon, titanium and aluminum? Where can i find transmutation tables or formulas to calculate the ...
2
votes
0answers
110 views

Intensity of particles with zenith angle dependence

The intensity of particles come to sea level depend to the zenith angle $I=Iv (\cos(z))^n$, where $z$ is the zenith angle and $n$ depend to the particle. I know the vertical intensity depend to the ...
1
vote
1answer
74 views

Astronomical measurements and data

For the sub-nuclear physics there is a database of the Particle Data Group, I was wondering if there was a similar on-line collection for astrophysics, such as energy absorption and emission spectra ...
1
vote
1answer
6k views

How is data physically written, read and stored inside hard drives?

How is data physically written, read and stored inside hard drives? Is it stored as differing spin of atoms inside the drive? Is that method the same in flash drives and SSDs?
3
votes
0answers
98 views

Where does one find pair-correlation functions for various materials?

What is the canonical source for finding pair-correlation functions for atoms in various materials? I am interested in both numeric computations and experimental measurements (like might be obtained ...