Astronomy Definition and 833 Threads

Homework Statement Hello I wanted clarification on freeman's law and the Tully fisher relationship. Am i correct to say that the tully fisher relationship that states L=kv^4 where L=luminosity of galaxy and v= max rotational speed of galaxy. only applies to edge-on spiral galaxies...

Homework Statement If at 09:30 21st may what would the RA of stars be at the zenith? I'm not sure if we can say that they are at 3.5hrs since we are in may? If a star is at RA 5hrs would at 09:30 would it be observable at 00:00. My thoughts are that you just add on 14.5 hrs to the...

Hi, I need to find an important, very recent paper in observational astronomy for a journal club presentation. It would help if it is short and easy to read :) . Could someone please suggest one to me? Thanks.

Homework Statement A double star located at a distance of 10 light years from us. The maximum angle between the stars, as seen from Earth, is 2 arcseconds. (1 arcsecond = 1 / 3600 degrees), we can assume that the stellar orbit is circular and that this angle gives us the real distance between...

Title is a little strange I know, let me explain better. I am doing my undergrad by the way. How can people, who for example are not in school for Physics/Astronomy, or don't have access to expensive telescopes, discover new things in Astronomy? For example, a while back a nine year old...

Homework Statement The measured velocities in elliptical galaxies pertain to the spread in random velocities of the stars; in spirals, to the rotational velocities of either the stars or the gas about the galaxy's center. When a spectrum is taken of an elliptical galaxy, we measure not the...

Hi, I'm looking for papers and general or specific information about the topic Astronomy in UV and X-ray Spectrum. Other than Wikipedia and Google sources, I would be interested in understanding the optical spectrum range and its limits, with respect to the materials used in this astronomy...

I want to study astronomy/astrophysics. But only two of the University of California offers astronomy or astrophysics. Would it be possible to major in physics and get a job in an astronomy related field or later get a masters in astronomy/astrophysics with a BS in physics?

Hello everyone, I am currently a freshman undergrad physics major at Stony Brook University. However, I've been having some doubts lately. I've been taking the advanced freshman physics courses last semester and this semester, and they more challenging than I expected. I'm not failing them...

Hi, I'm reading about the discovery of the cosmic microwave background radiation and don't understand this part ... What power does a source called with liquid helium produce and how is it related to the amplifier circuits ? I don't get what they did and why ? Thanks !

So I already graduated with a BS in Physics, but am considering applying to Astronomy grad schools. I don't have any coursework or research projects in it, but plan to start research with an Astro prof soon. As far as coursework, how necessary is it to have some when applying to Astro grad...

Homework Statement The question asks for the fraction of all 2M(sun) stars ever made in the Galaxy that are still burning on the main sequence. It assumes star formation at constant rate. The age of the Galaxy is 10GYRS To do this I imagine you use the salpeter IMF and find the constant...

Hi, I'm a high school junior and have the for as long as I can remember been interested in the sciences. In the past few years my love for science has focused in on space. I've been starting to plan for college and have been mostly looking at getting into astronomy. However, physics and...

Hello! I'm going to apply for a bachelor in a year. I haven't decided what I want to major in, but my top choices are astronomy (astrophysics) and nanotechnology (the course is called "Nanotechology, energy and materials"). I myself am more interested in the universe, space etc. I was almost...

I teach a semester-long Astronomy elective for juniors and seniors at an independent college preparatory high school. For the past few years, I have used Chaisson and McMillan's Astronomy: A Beginner's Guide to the Universe, which has served my purposes well. The course will be changing so...

So I heard that some physics and astronomy graduate programs are going through major funding issues right now. For example, one school I know only accepted about 5 students out of 150 for the phD admissions this year for their Astronomy dept (they're haven't been super-competitive like that in...

For my undergraduate, I'll be majoring in physics, with the intent to move on to graduate school for astronomy. In doing this, how helpful would it be to attend a school that offers an emphasis or track in astronomy or astrophysics alongside the physics major? Should I consider it to be a...

Typical motions of one plate relative to another are 1 centimeter per year. At this rate, how long would it take for two continents 3,000 km apart to collide? I don't know where to start or what formula to use.

Moon rocks containing uranium 238, decays to lead with a half life of 4.5 billion yrs. The lunar rock sample you're invistigating contains half of the original uranium 238. How old is the rock? How would I go about solving this? What formula should I use?

Hello! I am a physicist. Although I think I understand quite well the laws of Newtonian physics and general relativity that explain the observable universe, I am a complete dummy in what concerns doing measurements in the universe. For instance, I have no idea how to measure the distance to a...

I would like to start a thread where we can post artistic or computer generated images of planets, stars, etc. This is mainly for artistic merit and not neccesarily realism in the photos. If you want, you can also post real astronomy images. Be sure to not break any copyrights. If you are...

What do people think of astronomy binoculars like the Celestron Skymaster 20x80? Are these too big for casual use, for example to take camping? I'm going to Arizona soon and I'm looking for something portable that gives me the most bang for my buck. Should I just get some smaller binoculars...

This is just a small part of one of my problems. I need to find the luminosity of a stellar population containing 100 solar mass stars and one 20 solar mass star. I think that the 20 solar mass star will dominate, but I am not sure. Here is the formula to use: L/Lsun = (M/Msun)^3.5 I...

A space probe initially moving in a 1 AU circular orbit around the sun (i.e. moving with the earth). The aim is to put this space probe in an orbit that will encounter Mars, using the least possible expenditure of rocket fuel (energy). This orbit, it turns out, is one in which perihelion...

I've often wondered why there is so much misinformation around the topic of the reasons that very massive main sequence stars are so luminous. It even shows up in books, but if we restrict to seemingly reliable internet sites, I'll bet that in 10 google hits of sites that offer an explanation...

Need helping comming up with an Astronomy Project - Its open to anything ? Hey guys, Man this year in a certain Astronomy Class, our year end project is not on something specific, its wide open. Anything to do with astronomy: Like, a poster on something certain, but our instructor...

Most of the sites here aren't very helpful for learning astrophysics. However, they are amazingly useful for learning more about astronomy in general (and many cover far more than what you will find in any book or textbook) http://www.solstation.com/ - amazing amounts of detail for many stars...

Need helping comming up with an Astronomy Project - Its open to anything ? Hey guys, Man this year in a certain Astronomy Class, our year end project is not on something specific, its wide open. Anything to do with astronomy: Like, a poster on something certain, but our instructor...

Hi...am pursuing B.tech 2nd yr in Civil Engineering from India. I am very much interested in Astronomy and Astrophysics. But as I am already into my engineering, I don't find any way for my interests. Can anyone help me with this? Please let me know if a Civil Engineering under graduate can...

if anyone could help with either of these questions, it would be greatly appreciated, thank you (: 1) how long does a day on the moon last and why? 2) how many times larger does the Earth look if you were on the moon,compared to seeing the moon from earth? (provide calculation) thanks a...

I am a mechanical engineering student but my passion has always been astrophysics, astronomy, and cosmology (I literally get butterflies when I learn about it). I chose not to get a degree in it because I was concerned about future job security as it is an extremely competitive field. My...

A light source has uniform intensity I(with respect to wavelength) within a circle of diameter 3 arcmin on the sky. The flux of radiation reaching the observer is 10^(−16) erg cm^(−2) s^(−1). Calculate the intensity of the light from this source. Relevent Equations: This is where my...

So I'm curious as to how much upper-div and graduate-level physics is actually used in astronomy (grad-level courses), since I hear a lot that they're very related. I'm pretty interested in the research in numerical simulations of star and galaxy formation. I've seen some general lecture notes...

I've been lurking these forums for a long time, but I never really bothered to sign up until recently. I am far from the level that most people are on here, but here goes anyway..also, apologies for the super long post. I wanted to be sure I explained as much as possible. I am attempting to...

http://weareallinthegutter.wordpress.com/2010/12/22/astronomy-bottlenecks What are your thoughts on this?

I have some very basic atronomy questions that either I did not get answers to when I googled it or did not get very good explanation on the subject. So asking it here in this forum. I hope you guys do not mind answering such basics. 1) When I get out of my house at night and look at the...

The situation is, a lot ppl that studied Astronomy in universities did at last not get a job that very much relevant to their specialities, but, if not some but most of them, had to choose a career in relatively Mathematics oriented field, like market analysis. The payscale is good, not much...

I didnt find an astronomy subforum on the Homework section so I decided to post here. If I have the period of a cepheid (2.5 for instance), how to find apparent and absolute magnitude ?

Didnt know if this is the write palce to put this, but I am stuck on this assingment and i think it must have an easy solution so if someone could point me in the right direction then it would be much appreciated. Homework Statement Using an appropriate software package, quantify the...

Hi, I hope this finds you all in good health. I am telecommunications engineer but now want to pursue my age old interest in astronomy. So I am planning to go for a Masters degree in September 2011 session from US. In this regard I seek answers to these questions: 1. What are the...

Astronomy -- pressures Homework Statement The gas pressure of the photosphere changes substantially from its upper levels to its lower levels. Near the top of the photosphere and the temperature is about 4500 K and there are about 1.6x10^16 gas particles per cubic centimeter. In the middle...

Hello all, I am studying for an Introductory Astronomy final and I came across an old exam with a few True and False Questions Supermassive black holes are found in the centres of large galaxies (Supermassive is tricky here, not sure on this) Inflation is the name we give to...

Hello All, I am studying for my introductory astronomy exam and I came about these two question; Galileo discovered a) radioactivity b) some moons of saturn c) 2 moon of Mars d) some moons of Jupiter e) the telescope I know he discovered 4 moons of Jupiter but "some" is a bit...

There's always a lot of talk about mathematical physics and mathematical biology within the topic of applied mathematics, but I've never heard of astronomy being thrown into the mix... Why is this? Are there applied mathematicians working in astronomical fields? What about celestial...

the late 19th century - were people aware of all the planets? did anyone have any idea of what the Earth looked like? the moon? other planets? when did someone first see the Earth and all the continents? what about telescopes...how were they in the late 1880s? could your average joe look at...

I have applied for this year's Astronomy Olympiad to be held on 28th November, 2010. I am 17 and study in my 12th grade. Now, I have just bought a Physics Olympiad book. Now, the problem is that I only have 9 days to prepare myself for the exam. Can anyone suggest on how should I go on to...

Homework Statement Compute the speed of debris seen hitting the inner ring of Supernova 1987A. Assume radius of inner ring is 0.7 light years. Homework Equations The Attempt at a Solution I'm not quite sure where to start. I thought about just using kinetic energy = 0.5mv^2 because I...

it is possible to do a masters degree in us in astronomy or astrophysics with a mechanical undergrad? Profile mechanical engineer with 60% aggregate and 10 backlogs// gre general test(440+790+3.5)// toefl 85+(exp) right from my childhood i was interested in space sciences and space programs...

Homework Statement A typical dust grain has a radius of 10-7 m and a mass of 10-14 g. How many dust particles are there in a molecular cloud containing 1000*Masssun of dusty gas if 1% of the cloud's mass is in the form of dust grains? Homework Equations The Attempt at a Solution...

First, these are not homework questions. I need to make a "quick" study guide (as to teach someone basics of astronomy) Kinda like a pocket reference Can someone answer these in "SHORT" form ? As simple and to the point as possible. ? What effect does Earth's rotation have on the...