Star Definition and 1000 Threads

Homework Statement The problem is assume Andromeda and the Milky Way are going to collide. the relative speed of them moving is 10^6m/s. assume each star has the radius of our sun (6.955*10^8m) the distance between each star is 3.1*10^18 m. how long will it take for a star to collide with...

National Geographic is featuring this star trail picture this week on their wallpaper page (found here http://ngm.nationalgeographic.com/your-shot/weekly-wrapper/2012/img/0812wallpaper-week-4-1_1600.jpg). In the picture though I was wondering why the star trails appear so much more dense on the...

Homework Statement In the context of image reconstruction using backprojection by CT scanners - Why / how does backprojection cause star blur? Homework Equations Figure 13 of http://depts.washington.edu/nucmed/IRL/pet_intro/intro_src/section4.html and Figure 25-16 of...

”True” proximity in plane and space (”Island and star best friends”) ”True” proximity in plane and space (”Island and star best friends”) (To read this post in a more pleasant format, click here. My questions are in that document though, you will find them in this post.) Recently I was on...

Homework Statement A 415V, 50 Hz three phase supply supplies three balanced loads which draw a total apparent power (S) of 38 kVA at a power factor of 0.78 lagging. The three loads are as follows: LOAD 1 (STAR): 10.6 kVA at a power factor of 0.57 lagging; LOAD 2 (DELTA): 20 kW...

Any help on where I start with this question. Need to convert each force into its horizontal and vertical components, but don't know any angles apart from the 70N force acting straight down.

Hi all. I have a question. Is there a way to calculate the altitude and azimuth of a star at a given time using as an input the altitude and azimuth of that star at an earlier time, without having to convert those coordinates to RA and DEC? The problem is that I want to calculate the position...

How does one analytically estimate star formation rate in a plasma cloud? Could someone lead me to original references? Kennicutt-Schmidt Law, I guess, is empirical.

How does one analytically estimate star formation rate in a plasma cloud? Could someone lead me to original references?

Homework Statement Under some circumstances, a star can collapse into an extremely dense object made mostly of neutrons and called a neutron star. The density of a neutron star is roughly 10^{14} times as great as that of ordinary solid matter. Suppose we represent the star as a uniform, solid...

Homework Statement A large, spherically symmetric collection of point particles of mass m move in circular orbits about a common center each with the same kinetic energy. If the only force acting is the mutual gravitational attraction of the particles, find the particle density (in the...

From the following, can anybody tell me where I am going wrong in my thinking? Cosmologists tell us that our telescopes can detect starlight that left a star 13.4 billion years ago. I say that is impossible for the following two reasons: 1. The Big Bang occurred 13.4 billion years. At...

Hi there! I'm developing a game that involves simulating a star system. I'm using the Unity engine and its physics engine. I've got gravity working perfect. I've also developed an algorithm that works out how much force you would need to apply to a body to start it orbiting around another...

Ok, I know neutron stars are mainly composed of neutrons. But also, they have some protons and normal nuclei at their surfaces. Is this crust of protons needed to keep the neutrons below stable? As in, if it disappeared, would the neutrons below start decaying back to protons to form its...

what creates the "star points" in telescope pictures of stars? it's a basic question. e.g. see this hi-rez Hubble Deep Space pic: http://upload.wikimedia.org/wikipedia/commons/9/9b/Hs-2004-07-a-full_jpgNR.jpg i count about three bright objects with pointy cross-like projections from...

When does helium fusion occur in an evolution of star? Well, i just need help in this confusing part of a star's life. First of all, when the sun finishes the H-fuel at core, why doesn't it immediatly use the H-fuel on the surface.. And then another doubt is, what causes the expansion of the...

It's given in my book that from the width of spectral lines you can determine whether or not it is a main sequence star... Not sure if astro-como or quantum.. Anyway, i need a detailed easy explanation of what is the width of spectral lines.. Secondly, if we know that how will we determine...

hey folks, i was wondering if anyone could give me help on a wee problem i have. using a distance of a star of 2.6pc from earth, how would one calculate the time it took for light to be seen on Earth today... ............... my books have rounded that 1pc = 3.3 ly so i would take 2.6...

Hey, So i just read 2 articles, the first talked about the mathematical problem of 'packing', IE how many smaller objects of the same size can fit inside a shape without overlapping or covering the boundaries of the shape. and the second article was talking about a recent neutron star that...

Yet to be confirmed, but they've discovered a star system with 9 planets! (And those are just the big detectable ones!) The two latest are (nearly) super Earths. (well, 12x and 32x Earth's mass...), probably rocky...

Hey guys, Been struggling with this for ages any help would be awesome. In Electrical engineering; Suppose you have a balanced multiphase star system with a given line voltage. The impedance of each phase is also know. If one of the coils is short circuited, calculate the line...

Hey guys, in class today we learned about the life cycle of a star and at the very first stage gravity pulls the helium or Hydrogen nuclei at such a speed that they fuse (nuclear fusion). As I understand it there is little gravity in space so where is this extra gravity coming from? Thanks...

The acretion process between a white dwar binary and blakc hole binary is significantly different as the black hole has no solid surface. So am I right to presume that a neutron star binary should be the same process but with higher energies than than white dwarf case?

Homework Statement Star A and B are at rest relative to Earth. Star A is 27 ly from Earth, and as viewed from Earth, Star B is located beyond (behind) star A. (a) Star A is 27 ly from Earth. A spaceship makes a trip from Earth to star A at a speed such that the trip from Earth to Star A takes...

Hello. I am wondering what are the properties of matter at the core of a neutron star. I read that it could be quark matter of strange matter, but overall uncertain. How can strange matter form if strange quarks decay very quickly into up quarks (the state of matter would last very shortly), and...

Assume there is a neutron star, it has a mass that is just short of what is required for it to collapse into a black hole. Now suppose there is an observer orbiting the neutron star. Assume that the neutron star and the observer are traveling at a very high velocity with respect to a second...

If only some stars become black holes what sets them apart from other stars, is it just size?

I have a qualitative question to ask: The Schwarzschild radius of matter is proportional to its mass. The actual radius of the matter, assuming it is spherical, is proportional to the cube root of its mass. This implies that the density required to form a Schwarzschild radius decreases as...

a. it rotates faster b. it is smaller c. it is more luminous d. it has stronger pulses I'm stumped on this practice question for my final. I'm thinking that a. and d. contradict each other since doesn't an older, slower rotating neutron strong emit longer, stronger pulses? C. seems to...

With its current mass, can Jupiter become a stable star? Suppose Jupiter was artificially compressed to only a fraction of its present size (a hypothetical situation occurring in at least one work of science fiction), would the gravity-radiation pressure equilibrium be reached at all? It appears...

Homework Statement An open cluster is observed to contain 1000 stars. Clusters contain many more low mass stars compared to high mass stars, reflecting the star formation process. This depen- dence of the number of stars formed in a given mass range is expressed in the so-called initial mass...

are all stars in some galaxy? i now get interested in the universe could anyone recommend some basic textbooks for me? i have a doctor degree in theoretical physics.

Homework Statement Suppose that you decide to look at a known binary star system. The system is too far away to resolve the individual stars, so it appears to be just one point of light. By looking at the spectrum of the system, though, you should be able to use the Doppler shift to determine...

How would someone find the mass of an AGN when a solar luminosity is given? I know you can't simply use the mass-luminosity relationship since that only applies to main sequence stars, right? Thanks.

Homework Statement Problem 4: http://www.nspsmo.org/_data/global/images/2010-11%20Sample%20Problems.pdf Homework Equations Second to last page in same document. The Attempt at a Solution I know how to solve everything but the minor chord lengths: CD, DE, EF The only thing I could think of...

Homework Statement How fast (as a percentage of light speed) would a star have to be moving so that the frequency of the light we receive from it is 11.0% higher than the frequency of the light it is emitting? Homework Equations (f_L)= (f_s)*(v+v_L)/(v+v_s) The Attempt at a...

I used to watch Dark Shadows when I was little. I can still hear the music. RIP Barnabas. http://www.tvguide.com/News/Darks-Shadows-Star-Jonathan-Frid-Death-Obit-1046239.aspx Oooh, Johhny Depp as Barnabas, I can't wait!

I have no problem with description of a small star's formation by gas and dust accretion. The problem I have is with a massive star. When enough material has accumulated to start the fusion of the star, a stellar wind will start and will clear away the gas and dust nearby. A heavier star would...

H3+ The original mothercloud was mostly H2 and He. It didn't have molecular species containing C, N, and O that are good at radiating away heat they pick up by jostling each other when the cloud contracts. So it was hard for the early clouds to contract by their own gravity, because they...

Can the star positions be predicted with any degree of accuracy? If so are there any variables that woukld dramaticaly challenge said predictions? I say they can be but i am being challenged on it and i don't have any sources to back it up. Anyone? Thanks i am just ! :shy: newbie and dummie...

Hi I am little confused by star resistors configuration. The problem is asking for equivalent resistor for the circuit. I have attached the image below (Image is little sloppy because I can't draw with a mouse :D). My logic is as follows: First I calculated R1 and R2 as parallel...

Homework Statement If a big star gives of wind , forming shock and then a bubble .. And then this bubble is driven by pressure Also as the bubble expands the surrounding mass gets added to it Does it make sense for the Total energy to increase ? Homework Equations The Attempt at a Solution

An image of a point source (star) at infinity produces an image using a converging lens of diameter 50mm and focal length 500mm. Calculate the diameter of the resulting image.(take wavelengthof light to be 4x10^-7m) I ask this because it is to do with seeing stars through a telescope. I think...

Is there a well-established theory for temperature and cooling processes of neutron stars as a function of time?

Problem: Relatively low mass stars can be shown to have their radii dependent on their mass as; R\proptoM1/2 From this, show that the temperature in kelvin at the centre of such a star can be estimated to be \approx24\times106(M/Msolar)1/2 Relevant Equations...

I am a writer of science fiction and I need to know some basics about space travel. I've read that it would take a ship 40 years to travel 1 parsec (3.26 light years) if the ship moved at 10% the speed of light. Does that sound right? Given that a futuristic ship could travel at this speed...

I have a set a of stars, each of which have a magnitude in the K band ( K ) and a 1 sigma uncertainty ( dK ) associated with it. For a program I'm writing, I need to see whether each star lies within a maximum K magnitude (K_max ) and a minimum K magnitude ( K_min ). I also need to find a...

I'm a yr 12 student doing a full year research assignment and i have decided to find the age of the star, Sirius. I have access to a pretty good telescope and equipment but I am not sure where to start. Suggestions anyone?

Neutron star is said to have masses so compact that 10 miles of it would have more mass than the sun. For example two neutron star collides, can a small fragment be separated from it forming a meteor? And if a small piece were to enter Earth atmosphere and reach land. Would the neutron star as...

Homework Statement What is the temperature of a star if the flux at 450 nm is measured to be 1.3 times the flux at 650 nm Homework Equations To determine monochromatic flux I use: 2πhv3/c2 ex-1 x= hv/kT The Attempt at a Solution So basically I plug in the...