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The Cosmic Perspective (9th Edition)
- Problem 1. Mass-Energy conversion in the Sun (Palen, et. al. 3rd Edition, Chapter 11, problems 38, 39) The Sun produces energy by converting mass m into energy E according to E = mc2 where c is the speed of light (c = 300,000 km/sec). Show that if the Sun produces 3.85 × 1026 joules (J) of energy per second, it must convert 4.3 billion kg of mass per second into energy. Note that 1 J/s is a watt (W), which may be more familiar to you. How much mass has the Sun lost over its lifetime (4.5 billion years)? The current mass of the Sun is 2 × 1030. What fraction of this mass has been converted into energy during the Sun’s lifetime?arrow_forwardAssume the observable Universe is charge neutral, and that it contains n nuclei (hydrogen plus helium nuclei, ignoring other elements). Take the helium mass fraction as 1/4. How many electrons are there in the observable Universe? Enter your answer in scientific notation with one decimal place. Value: n = 4*1080arrow_forwardWhite Dwarf Size II. The white dwarf, Sirius B, contains 0.98 solar mass, and its density is about 2 x 106 g/cm?. Find the radius of the white dwarf in km to three significant digits. (Hint: Density = mass/volume, and the volume of a 4 sphere is Tr.) 3 km Compare your answer with the radii of the planets listed in the Table A-10. Which planet is this white dwarf is closely equal to in size? I Table A-10 I Properties of the Planets ORBITAL PROPERTIES Semimajor Axis (a) Orbital Period (P) Average Orbital Velocity (km/s) Orbital Inclination Planet (AU) (106 km) (v) (days) Eccentricity to Ecliptic Mercury 0.387 57.9 0.241 88.0 47.9 0.206 7.0° Venus 0.723 108 0.615 224.7 35.0 0.007 3.4° Earth 1.00 150 1.00 365.3 29.8 0.017 Mars 1.52 228 1.88 687.0 24.1 0.093 1.8° Jupiter 5.20 779 11.9 4332 13.1 0.049 1.30 Saturn 9.58 1433 29.5 10,759 9.7 0.056 2.5° 30,799 60,190 Uranus 19.23 2877 84.3 6.8 0.044 0.8° Neptune * By definition. 30.10 4503 164.8 5.4 0.011 1.8° PHYSICAL PROPERTIES (Earth = e)…arrow_forward
- Models of the first star-forming clouds indicate that they had a temperature of roughly 150 K and a particle density of roughly 400,000 particles per cubic centimeter at the time they started trapping their internal thermal energy. ▼ Part A Estimate the mass at which thermal pressure balances gravity for these values of pressure and temperature. Express your answer in kilograms. —| ΑΣΦ Mcloud Submit Part B = Mcloud How does that mass compare with the Sun's mass? Express your answer in solar masses. Submit Request Answer = ΤΙ ΑΣΦ Request Answer ? ? kg MSun Reviewarrow_forwardWhen observed from Earth, the wavelengths of light emitted by a star are shifted toward the red end of the electromagnetic spectrum. Why does this redshift occur? A The star is at rest relative to Earth. The star is moving toward Earth at decreasing speed. The star is moving toward Earth at increasing speed. D The star is moving away from Earth. DOOOarrow_forwardA star of mass 7x 100 kg is located at m and is moving with a velocity of 1.3x10, 1.1 x 10,0 m/s. Part 1 Your answer is partially correct. (a) During a time interval of 1 x 10 seconds, what is the change in the planet's velocity? i21.2258002 -21.2258002 > m/sarrow_forward
- Let us imagine that the spectrum of a star is collected and we find the absorption line of Hydrogen-Alpha (the deepest absorption line of hydrogen in the visible part of the electromagnetic spectrum) to be observed at 656.5 nm instead of 656.3 nm as measured in a lab here on Earth. What is the velocity of this star in m/s? (Hint: speed of light is 3*10^8 m/s; leave the units off of your answer) Question 4 of 7 A Moving to another question will save this response. 1 6:59 & backsarrow_forwardA stellar black hole may form when a massive star dies. The mass of the star collapses down to a single point. Imagine an astronaut orbiting a black hole having eight times the mass of the Sun. Assume the orbit is circular. a. Find the speed of the astronaut if his orbital radius is r = 1 AU. b. Find his speed if his orbital radius is r = 11.8 km. c. CHECK and THINK: Compare your answers to the speed of light in a vacuum. What would the astronauts orbital speed be if his orbital radius were smaller than 11.8 km?arrow_forwardThe meter was redefined as a reference to Earth, then to krypton, and finally to the speed of light. Why do you think the reference point for a meter continued to change?arrow_forward
- 1. Your friend recorded the location of a certain explosion at (11 [m] , 13 [m]). If he is aboard a bus moving at a velocity 0.6 with respect to your reference frame, what is the coordinates of the event in your reference frame? A. (8 (m] , 4 [m]) B. (4 [m] ,8 (m]) C. (24.5 [m] , 23.5 [m]) D. (23.5 (m] , 24.5 [m]) 2. Kim celebrated his birthday at (12 [m] , 13 [m]). If he took the exam at (6 [m], 10 [m]), what is the (time interval, space interval) of the two events for a person in a rocket moving at 0.50 to the left? A. (3/3 (m],0 [m]) B. (0,3/3 (m)) C. (5V3 [m], 4v3 [m]) D. (4/3 [m], 5v3 [m]) 3. A charged particle is observed in two inertial reference frames. Which of the following statements is/are TRUE about the particle? I. The charge is covariant. II. The mass is invariant. III. The momentum is invariant. А. П only B. I and II only C. II and III only D. I, II and IIIarrow_forwardGalaxy B moves away from galaxy A at 0.501 times the speed of light. Galaxy C moves away from galaxy B in the same direction at 0.729 times the speed of light. How fast does galaxy C recede from galaxy A? Express your answer as a fraction of the speed of light. Galaxy C recedes from Galaxy A at Carrow_forwardThe Andromeda Galaxy, M31, is the closest large spiral Galaxy to our Milky Way. When we lookat its chemical spectrum, we see that it's hydrogen alpha emission line has an observed wavelength of 655nm. a. Calculate z, being careful with the sign b. How fast is it moving in km/s c. Is it redshifted or blueshifted? Is it moving toward or away from us?arrow_forward
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