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What is a standard candle?
What is a standard candle?

... We can use this equation to find the distances to objects in the universe using the concept of a standard candle ...
ph507lecnote06
ph507lecnote06

... At first glance, the spectra of different stars seem to bear no relationship to one another. In 1863, however, Angelo Secchi found that he could crudely order the spectra and define different spectral types. Alternative ordering schemes appeared in the ensuing years, but the system developed at the ...
Binaries
Binaries

... Gravitational force: ...
Astronomy 112: The Physics of Stars Class 1 Notes: Observing Stars
Astronomy 112: The Physics of Stars Class 1 Notes: Observing Stars

... However, we’re usually more interested in the total number of atoms of a given type than in the number that are in a given quantum state. One way of figuring this out would be to try to measure lines telling us about many quantum states, but on a practical level this can be very difficult. For examp ...
1/20/09 301 Physics Chapter 12 The Family of Stars Triangulation
1/20/09 301 Physics Chapter 12 The Family of Stars Triangulation

... – Superimposed on this orbital motion are small random motions of about 20 km/sec – In addition to their motion through space, stars spin on their axes and this spin can be measured using the Doppler shift technique – young stars are found to rotate faster than old stars ...
stellar spectra instructor notes
stellar spectra instructor notes

OUR SOLAR SYSTEM
OUR SOLAR SYSTEM

... our universe is. To give a sense of its vast scale, we’ve devoted the bottom of this and the next four stories to a linear scale of the cosmos. The distance to each object represents the amount of space its light has traversed to reach Earth. Because the universe is expanding, a distant body will ha ...
Presentation file
Presentation file

... 4. Sub-photospheric – violent mode or strange mode instabilities Glatzel et al, Guzik, Stothers & Chin Caused by increase in opacity due to Fe at base of photosphere leading to ionization induced instability ...
STELLAR CLASSIFICATIONS: TYPE “O” STARS
STELLAR CLASSIFICATIONS: TYPE “O” STARS

... enough so that when the star dies, its core turns into a neutron star. The most massive class “A” stars weigh in at 2.1 times that of the sun. This is enough mass to cause the core to collapse into a black hole. Luminosity: While heavy, these stars only shine 5 to 25 times brighter than the sun. Thi ...
Chemical Evolution
Chemical Evolution

... All stellar components of the Milky Way contain very old stars (but where are first stars?)  Little evidence for variations in stellar IMF, over wide range of metallicity, age, local density…  Small-scale problems with CDM persist, but things are evolving rapidly and the next few years will reall ...
Triangulation Trigonometric Parallax
Triangulation Trigonometric Parallax

... – Superimposed on this orbital motion are small random motions of about 20 km/sec – In addition to their motion through space, stars spin on their axes and this spin can be measured using the Doppler shift technique – young stars are found to rotate faster than old stars ...
THE GALACTIC GAZETTE The Astronomical Society of Southern New England Next Meeting
THE GALACTIC GAZETTE The Astronomical Society of Southern New England Next Meeting

... a radius of about 103 million miles—about 10% larger than Earth’s orbit—with a resolution of 30,000 miles, only 0.03% of the radius. Live fast, die young…leave no corpse The simulations revealed that a supermassive star burns hydrogen at a furious rate for under 2 million years—a mere blink of a cos ...
Project 4: The HR diagram. Open clusters
Project 4: The HR diagram. Open clusters

... stars do not fall randomly on the graph; rather they are confined to specific regions. This  tells you that there is some physical relationship between the luminosity and temperature  of a star. From the figure, one sees that most stars fall along a diagonal strip from high  temperature,  high  lumi ...
X-ray binaries
X-ray binaries

SGR and AXP – are they magnetars?
SGR and AXP – are they magnetars?

... accelerating the particles being inversely related to the spin period. Pair production will stop when the potential drops below a threshold, so the models predict that radio emission will cease when the period exceeds a value that depends on the magnetic field strength and configuration. Here we sho ...
Stars A globular cluster is a tightly grouped swarm of stars held
Stars A globular cluster is a tightly grouped swarm of stars held

... night sky far from city lights, you can see only about 3,000 of them without using binoculars or a telescope. Stars, like people, have life cycles -- they are born, pass through several phases, and eventually die. The sun was born about 4.6 billion years ago and will remain much as it is for another ...
X-ray binaries
X-ray binaries

... Many sources are found in globular clusters. Also there are more and more LMXBs found in more distant galaxies. In optics the emission is dominated by an accretion disc around a compact object. Clear classification is based on optical data or on mass function derived from X-ray observations. If a so ...
H-R Diagram
H-R Diagram

... A star’s energy comes from nuclear fusion, a process in which two hydrogen atoms join to form a helium atom. ...
Lecture 17
Lecture 17

... This is really tiny. We cannot resolve multiple images when the separation is only 1 miliarcsecond. This regime of lensing is called “microlensing”. For experiments trying to detect stellar-mass lenses in the Galactic halo using stars in the Large Magellanic cloud (LMC) which is 50 kpc away, you can ...
Stellar Evolution
Stellar Evolution

... from the Earth • all the stars formed at about the same time Determining the distance and age to a globular cluster is much easier than trying to find the distances and ages of a million random stars! Laboratories for understanding how stars of different masses evolve ASTR 1120: Spring 2005 ...
Cepheid Variable Star RS Puppis
Cepheid Variable Star RS Puppis

Measuring Stars` Properties - Test 1 Study Guide
Measuring Stars` Properties - Test 1 Study Guide

... •  For a few close, big stars, they can be seen in a telescope as non-point objects •  Measure angular size; if know distance then get size of star Example: Betelgeuse 300 times larger radius than the Sun •  If further away but a binary star, get size of stars when they eclipse each other ! length o ...
Measuring Astronomical Distances
Measuring Astronomical Distances

... The Ancient Universe Stars and other “heavenly bodies” move on transparent spheres The Earth is the center of the universe Aristotle 350 BC ...
What we can measure
What we can measure

The Formation of High Mass Stars
The Formation of High Mass Stars

... Two new mechanisms to overcome radiation pressure barrier to achieve high mass star formation  high mass binary system — 3-D Rayleigh-Taylor instabilities in radiation driven bubbles appear to be important in allowing accretion onto protostellar core — Protostellar outflows resulting in optically t ...
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Future of an expanding universe

Observations suggest that the expansion of the universe will continue forever. If so, the universe will cool as it expands, eventually becoming too cold to sustain life. For this reason, this future scenario is popularly called the Big Freeze.If dark energy—represented by the cosmological constant, a constant energy density filling space homogeneously, or scalar fields, such as quintessence or moduli, dynamic quantities whose energy density can vary in time and space—accelerates the expansion of the universe, then the space between clusters of galaxies will grow at an increasing rate. Redshift will stretch ancient, incoming photons (even gamma rays) to undetectably long wavelengths and low energies. Stars are expected to form normally for 1012 to 1014 (1–100 trillion) years, but eventually the supply of gas needed for star formation will be exhausted. And as existing stars run out of fuel and cease to shine, the universe will slowly and inexorably grow darker, one star at a time. According to theories that predict proton decay, the stellar remnants left behind will disappear, leaving behind only black holes, which themselves eventually disappear as they emit Hawking radiation. Ultimately, if the universe reaches a state in which the temperature approaches a uniform value, no further work will be possible, resulting in a final heat death of the universe.
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