The amount of light available for astrophysical analysis are usually so small.对天体物理分析来说,可接收到的天体光量是相当小的.Much astrophysical information is to be obtained from the intensity of absorption or emission lines.许多天体物理信息要根据吸收线或发射...
Some pulsars keep time better than the earth's most accurate clocks.某些脉冲星发送脉冲比地球上最精确的时钟都准时。They have discovered now , previou sly unimagined objects - pulsars, quasars, and black holes.他们发现了以往想象不到的新客体 —— 脉冲星 、 类星体和黑...