The core of a star collapses during what event, forming a neutron star?
gravitational
spark
blast
supernova
The average particle energy needed to observe 19 GeV . (a) What unification of forces is estimated to be 10 is the rest mass in kilograms of a particle that has a rest mass 19 of 10 GeV/c 2 ? (b) How many times the mass of a hydrogen atom is this? 14. The peak intensity of the CMBR occurs at a wavelength of 1.1 mm. (a) What is the energy in eV of a 1.1-mm photon? (b) 9 There are approximately 10 photons for each massive 9 particle in deep space. Calculate the energy of 10 such photons. (c) If the average massive particle in space has a mass half that of a proton, what energy would be created by converting its mass to energy? (d) Does this imply that space is “matter dominated”? Explain briefly. (a) What Hubble constant corresponds to an approximate 10 age of the universe of 10 y? To get an approximate value, assume the expansion rate is constant and calculate the speed at which two galaxies must move apart to be separated by 1 Mly (present average galactic separation) in a time of 10 10 y. (b) Similarly, what Hubble constant corresponds to a 10 universe approximately 2×10 -y old? 16. Show that the velocity of a star orbiting its galaxy in a circular orbit is inversely proportional to the square root of its orbital radius, assuming the mass of the stars inside its orbit acts like a single mass at the center of the galaxy. You may use an equation from a previous chapter to support your conclusion, but you must justify its use and define all terms used. The core of a star collapses during a supernova, forming a neutron star. Angular momentum of the core is conserved, and so the neutron star spins rapidly. If the initial core radius 5 is 5.0×10 km and it collapses to 10.0 km, find the neutron star’s angular velocity in revolutions per second, given the core’s angular velocity was originally 1 revolution per 30.0 days. Using data from the previous problem, find the increase in rotational kinetic energy, given the core’s mass is 1.3 times that of our Sun. Where does this increase in kinetic energy come from? 19. Distances to the nearest stars (up to 500 ly away) can be measured by a technique called parallax, as shown in Figure 34.26. What are the angles θ 1 and θ 2 relative to the plane of the Earth’s orbit for a star 4.0 ly directly above the Sun? 20. (a) Use the Heisenberg uncertainty principle to calculate the uncertainty in energy for a corresponding time interval of.