Christensen / De Martin / Shida Cosmic Collisions

The Hubble Atlas of Merging Galaxies
1. Auflage 2010
ISBN: 978-0-387-93855-4
Verlag: Springer
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 142 Seiten

Like no other telescope ever invented, the NASA/ESA Hubble Space Telescope has given us magnificent high resolution views of the gigantic cosmic collisions between galaxies. Hubble's images are snapshots in time and catch the colliding galaxies in different stages of collision. Thanks to a new and amazing set of 60 Hubble images, for the first time these different stages can be put together to form a still-frame movielike montage showing the incredible processes taking place as galaxies collide and merge. The significance of these cosmic encounters reaches far beyond aesthetics. Galaxy mergers may, in fact, be some of the most important processes that shape our universe. Colliding galaxies very likely, hold some of the most important clues to our cosmic past and to our destiny. It now seems clear that the Milky Way is continuously undergoing merging events, some small scale, others on a gigantic scale. And the importance of this process in the lives of galaxies is much greater than what was previously thought.

Autoren/Hrsg.

Christensen, Lars Lindberg

De Martin, Davide

Shida, Raquel Yumi

Inhaltsverzeichnis

1;Table of Contents;8
2;Prerace;10
3;Chapter 1 Galaxies: The Big Picture;12
3.1;'' Mapping the Milky way is much like trying to map a crowded, foggy city from a single vantage point inside the murk,'';13
3.1.1;Discovery of the Milky Way;13
3.1.2;Measuring and Weighing the Milky Way;17
3.2;"Galaxies are islands floating in the large cosmic ocean, each filled with myriads of stars.";18
3.3;"A speck of dust near a rice grain in a disk one and a half times greater than the Moon's orbit-that's our place in the Milky Way!";19
3.4;"The Great Debate was arguably as important to our world view as some of the discoveries made by the explorers at sea in the seventeenth century.";21
3.4.1;Other Island Universes;21
3.5;"The protagonists left the auditorium in New York without a resolution to the immensely important problem of the scale of the universe.";22
3.6;"The Milky Way is just one of many galaxies scattered throughout the universe.";23
3.6.1;Different Types of Galaxies;23
3.7;"These oddball galaxies were largely ignored by astronomers until the mid-1950s, but have since turned out to be crucial for our understanding of how galaxies evolve.";25
3.7.1;Spiral Galaxies;27
3.8;"In the currently favored picture of galaxy formation, called the merger hypothesis, present-day ellipticals formed as a result of merger between these earlier building blocks.";28
3.9;"The origin of the spiral structure has been a matter for vigorous discussion among scientists for decades.";30
3.10;"Despite the smooth, featureless appearance and the slower motion of their stars, elliptical galaxies are quite exciting dynamical systems.";34
3.10.1;Elliptical Galaxies;34
3.11;"The Atlas of Peculiar Galaxies was a pioneering attempt to solve the mystery of the bizarre shapes of galaxies observed.";39
3.11.1;Irregular and Peculiar Galaxies;39
3.12;"Astronomers are now convinced that the galaxy collisions play a fundamental role in establishing the many different galaxy shapes.";41
4;Chapter 2 How do Galaxies form and evolve?;44
4.1;"Galaxy clusters are the largest gravitationally bound object we know.";46
4.2;"The first galaxies formed within the first five percent of the universe's lifetime. Compared to an average human lifespan the universe had not yet reached school age.";48
4.2.1;In the Bebinning;48
4.3;"The creation of the supermassive black hole appears to play a key role in actively regulating the growth of a galaxy.";49
4.3.1;Evolution of Galaxies;49
4.3.2;Evolution of sprial Galaxies;49
4.4;"After the collision, the captured stars rock back and forth and form the faint shells just as water forms ripples when we toss a rock into a pond.";51
4.4.1;Evolution of Elliptical Galaxies;51
4.5;"The resulting galaxy is dominated by stars that orbit the center in a complex, and random, web of orbit, just the behavior we see in elliptical galaxies.";53
5;Chapter 3 Galaxy collisions;56
5.1;"Our usual impression of the starry night sky is that of a nearly motionless dome. A single human life span is just the blink of an eye on a cosmological time scale.";57
5.2;The First Observations;57
5.3;"During the early part of the Second World War, Homberg devised an extraordinarily clever experiment in a darkned barn in Sweden.";60
5.3.1;The First Simulations;60
5.4;"A major aspect of this extra star formation in colliding galaxies was only properly revealed when Hubble's sharp eyes were turned towards selected systems.";64
5.4.1;Star Birth;64
5.5;"A supermassive black hole located at a galaxy's core feeds on the gas and disrupted stars coming from the surrounding galaxy.";67
5.5.1;Feefing Black Holes;67
6;Chaptetr 4 The Colliding Galaxies Movie;74
6.1;" It is clear that much of the diversity of observed galaxy collisions is due in part to the varying angles we observe them from and different times in their lives at which we observe them." ;75
6.2;" The outcome of a collision depends not only on how close the galaxies come to each other but also on how the approach angle and the spin of the galaxies align. " ;80
6.3;" Just as a pebble thrown into a pond creats an outwardly moving circular wave,a propagating density wave is generated at the point of impact and spreads outward. ";83
6.3.1;Splashing Collisions;83
6.3.2;Messy Mergers;83
6.3.3;Galaxy Groups;86
6.4;" When two galaxies pass close by each other the gravatational force affecting the stars nearest to the approaching galaxy is vastly greater than that experienced by that stars at the other end.";88
6.4.1;Tidal Traumps;88
6.4.2;Destroying Dwarfs;91
7;Chapter 5 The End;94
7.1;Milkomeda, the End of the Milky Way ;95
8;Chapter 6 Gallery;102
9;The Authors;139
10;Resources;141
11;Image Credits;142