No nuclear reactions occur in the interior of a white dwarf. its brilliance comes from stored heat. therefore, the fate of an isolated white dwarf is to slowly lose its stored energy and dim over a long period of time. however, if a white dwarf is a member of a binary-star system with specific properties, the white dwarf can become explosively active. label the components of such a binary-star system capable of producing a nova event.
mass-transfer stream
accretion disk
main-sequence or giant companion star
white dwarf

Space-time metric ds2= -dt2+at2dx2+bt2dy2+ct2dz2 (a)how does the area of a rectangle with vertices at ( x=0, y=0, z=0 ), (1,0,0 ), ( 0,1,0 ) and (1,1,0 ) changes with time? (b) if a photon moving in the x direction starts from the origin at t=1, when does it reach x=l? (ds=0 for the trajectory of a photon.) (c) the proper time for a particle is defined by cd=ds. what is the proper time for a particle to move along the trajectory ( x(t)=t, y(t)=0, z(t)=0 ) from t=0 to 1 ? what is the condition on the parameter a so that the velocity of the particle never exceeds the speed of light ?

Lymphocytes known as blastocysts make antibodies that fight infection. select the best answer from the choices provided t f

Complete the statement about memory improvement. ( )involves organizing and breaking down information into easier groups to expand capacity. rehearsal is the verbal repetition of information. these techniques are especially important for the improvement of ( ) memory.