Universe: Stars And Galaxies
6th Edition
ISBN: 9781319115098
Author: Roger Freedman, Robert Geller, William J. Kaufmann
Publisher: W. H. Freeman
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Chapter 24, Problem 29Q
To determine
The possibility for alien astronomer for observing the blazar and explaining it with the help of a drawing.
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Most of the stars we can see with the unaided eye in our night sky are hundreds or even thousands of lightyears away from Earth. (The very closest ones are only a few dozen lightyears away, but most are much further.) The vast majority of stars in our galaxy are many tens of thousands of lightyears away. IF intelligent life existed on planets orbiting some of these stars – and that’s a huge IF! – comment on the likelihood and practicality of (a) visiting, (b) communicating with, or (c) verifying the existence of those life forms. Describe how you might go about approaching EACH of these three tasks, or if you think they are even possible. (One or two sentences for each part would be appropriate.)
Please answer the question and its subquestions entirely! This is one question with two subquestions. According to the official Bartleby guidelines, I am alowed to have up to two subquestion!
1)
Astronauts orbiting the earth in the space shuttle experience a force of gravity that is
several times greater than the Fgrav experienced on Earth's surface.
several times smaller than the Fgrav experienced on Earth's surface.
a fraction greater than the Fgrav experienced on Earth's surface.
a fraction smaller than the Fgrav experienced on Earth's surface .
... nonsense! Orbiting astronauts do not experience any gravitational pull from the earth.
a)
A space shuttle is in orbit about the earth at an altitude where the acceleration due to gravity is 8.70 m/s 2. What is the shuttle's speed at this altitude?
2.65 × 10 3 m/s
7.45 × 10 3 m/s
7.68 × 10 3 m/s
7.91 × 10 3 m/s
b)
A 9 × 10 3 kg satellite with an…
In a globular cluster, astronomers (someday) discover a star with the same mass as our Sun, but consisting entirely of hydrogen and helium. Is this star a good place to point our SETI antennas and search for radio signals from an advanced civilization?
Group of answer choices
No, because such a star (and any planets around it) would not have the heavier elements (carbon, nitrogen, oxygen, etc.) that we believe are necessary to start life as we know it.
Yes, because globular clusters are among the closest star clusters to us, so that they would be easy to search for radio signals.
Yes, because we have already found radio signals from another civilization living near a star in a globular cluster.
No, because such a star would most likely not have a stable (main-sequence) stage that is long enough for a technological civilization to develop.
Yes, because such a star is probably old and a technological civilization will have had a long time to evolve and develop there.
Chapter 24 Solutions
Universe: Stars And Galaxies
Ch. 24 - Prob. 1QCh. 24 - Prob. 2QCh. 24 - Prob. 3QCh. 24 - Prob. 4QCh. 24 - Prob. 5QCh. 24 - Prob. 6QCh. 24 - Prob. 7QCh. 24 - Prob. 8QCh. 24 - Prob. 9QCh. 24 - Prob. 10Q
Ch. 24 - Prob. 11QCh. 24 - Prob. 12QCh. 24 - Prob. 13QCh. 24 - Prob. 14QCh. 24 - Prob. 15QCh. 24 - Prob. 16QCh. 24 - Prob. 17QCh. 24 - Prob. 18QCh. 24 - Prob. 19QCh. 24 - Prob. 20QCh. 24 - Prob. 21QCh. 24 - Prob. 22QCh. 24 - Prob. 23QCh. 24 - Prob. 24QCh. 24 - Prob. 25QCh. 24 - Prob. 26QCh. 24 - Prob. 27QCh. 24 - Prob. 28QCh. 24 - Prob. 29QCh. 24 - Prob. 30QCh. 24 - Prob. 31QCh. 24 - Prob. 32Q
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- In this experiment, as a form of sheltering-at-home fantasy, we adopt a science=fiction scenario. It’s the year 2520 and you are an astronaut working for a private entity simply called The Company. The CEO of The Company is the 8th clone of Elon Musk. Elon 9 has provided you with a small interstellar spacecraft about a million times faster than anything we can conceive of today. It is your job to check out the potential habitability of a few relatively near potentially habitable planets to see if human colonies can be established there to mine materials for the latest version of the Tesla automobile. But there is a problem. Shortly before your launch, a solar-system-wide pandemic ground human economy to a standstill. So Elon 9 had to cut corners. The only device he could afford for you to measure gravity acceleration on the subject planets is a pendulum with a length of 100 cm. After landing, you will determine the gravitational acceleration at the surface of…arrow_forwardSuppose we find an Earth-like planet around one of our nearest stellar neighbors, Alpha Centauri (located only 4.4 light-years away). If we launched a "generation ship" at a constant speed of 1500.00 km/s from Earth with a group of people whose descendants will explore and colonize this planet, how many years before the generation ship reached Alpha Centauri? (Note there are 9.46 ××1012 km in a light-year and 31.6 million seconds in a year.arrow_forwardSuppose a hypothetical universe is expanding (at some moment in time) at a rate of H. What would the density of this universe need to be (at this same moment in time) in order for it to be spatially flat? Value: H = 80 km s-1 Mpc-1 Give your answer in units of (kg m-3), in scientific notation with one decimal place (two sig figs). Please show work because I have trouble following alongarrow_forward
- 1.004 1.002 1.000 0.998 0.996 0.994 0.992 0.990 10 20 30 40 50 t-2458543 (BJD] From the data, determine: A. The orbital period of the planet (in years) B. The orbital distance of the planet (in AU) C. The radius of the planet (in Jupiter radii, where 1 Jupiter radius = 0.10049 solar radii) Relative FLuxarrow_forwardA galaxy's rotation curve is a measure of the orbital speed of stars as a function of distance from the galaxy's centre. The fact that rotation curves are primarily flat at large galactocen- tric distances (vrot(r) ~ constant) is the most common example of why astronomer's believe dark matter exists. Let's work out why! Assuming that each star in a given galaxy has a circular orbit, we know that the accelera- tion due to gravity felt by each star is due to the mass enclosed within its orbital radius r and equal to v?/r. Here, ve is the circular orbit velocity of the star. (a) Show that the expected relationship between ve and r due to the stellar halo (p(r) xr-3.5) does not produce a flat rotation curve. (b) Show that a p(r) ∞ r¯² density profile successfully produces a flat ro- tation curve and must therefore be the general profile that dark matter follows in our galaxy.arrow_forwardUsing our example from the previous unit, let's try to determine the Hubble time for this example universe. You were given that a good representative galaxy receded at a speed of 4000 km/s and was found to be 20 Mpc away. With that in mind, what would the age of that universe be in years (aka what is that universe's Hubble time)? Go ahead and take the number of kilometers per Mpc to be approximately 3.1*10^19 km/Mpc. While this problem may look scary at first, this is really just bringing you full circle to one of the unit conversion problems you encountered at the beginning of this course.arrow_forward
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