Horizons: Exploring the Universe
Michael A. Seeds
Format: PDF / Kindle (mobi) / ePub
With their best-selling astronomy textbook, HORIZONS, authors Mike Seeds and Dana Backman help you understand your place in the universe--not just your location in space but your role in the unfolding history of the physical universe. To achieve this goal, they focuses on two central questions: "What Are We?" which highlights your place as a planet dweller in an evolving universe, guiding you to better understand where we came from and how we formed; and "How Do We Know?" which provides insights into how the process of science can teach us more about what we are.
Low-mass stars form in such a cloud, but low-mass stars are not powerful enough to keep the star formation going. When massive stars form, however, their intense radiation and eventual supernovae explosions push back the surrounding gas and compress it. This compression in turn can trigger the formation of more stars, some of which will be massive. Thus, a few massive stars can drive a continuing cycle of star formation in a giant molecular cloud. A collapsing cloud of gas breaks up because of.
Proﬁle 9 | Uranus 359 363 369 Celestial Proﬁle 10 | Neptune 395 401 CONTENTS xi How Do We Know? 20-1 The Nature of Scientiﬁc Explanation Part 5: Life 426 20-2 UFOs and Space Aliens 438 Chapter 20 | Life on Other Worlds 425 20-1 THE NATURE OF LIFE 426 20-2 THE ORIGIN OF LIFE 430 20-3 COMMUNICATION WITH DISTANT CIVILIZATIONS Concept Art Portfolios 437 DNA: The Code of Life AFTERWORD 428–429 443 APPENDIX A UNITS AND ASTRONOMICAL DATA APPENDIX B OBSERVING THE SKY GLOSSARY 445.
Change in the heavens and therefore 50 PART 1 | THE SKY had to lie below the sphere of the moon. In that case, the new star should show parallax, meaning that it would appear slightly too far east as it rose and slightly too far west as it set. But Tycho saw no parallax in the position of the new star, so he concluded that it must lie above the sphere of the moon and was probably on the starry sphere itself. This contradicted Aristotle’s conception of the starry sphere as perfect and.
Unchanging. No one before Tycho could have made this discovery because no one had ever measured the positions of celestial objects so accurately. Tycho had great conﬁdence in the precision of his measurements, and he had studied astronomy thoroughly, so when he failed to detect parallax for the new star, he knew it was important evidence against the Ptolemaic theory. He announced his discovery in a small book, De Stella Nova (The New Star), published in 1573. The book attracted the attention of.
Ultraviolet and X-ray part of the spectrum. Since then many space telescopes have made high-energy observations from orbit. CHAPTER 5 | LIGHT AND TELESCOPES 89 ■ Hubble Figure 5-21 The Hubble Space Telescope orbits Earth only 569 km (353 mi) above the surface. Here it is looking to the upper left. The James Webb Space Telescope, planned to replace Hubble, will be over six times larger in collecting area. It will not have a tube but will observe from behind a sun screen. The infrared.