1.  Interplanetary space is cold, lonely, and hostile.

2.  Otherwise the planetesimals would not have been cold enough to trap the volatile gases, which would have been dispersed among the other tenuous matter in interplanetary space.

3.  Primitive bacteria could have hitched a ride on rock fragments crossing interplanetary space and seeded life on Earth, he says.

4.  Ripples in magnetic fields wafting through interplanetary space have been detected by a space probe and converted into sound you can hear online.

5.  They knew that interplanetary space is an active region of dust and gas, winds of charged solar particles, micrometeorites, asteroids and comets.

6.  Japan is only the third country after the United States and Russia to attempt an interplanetary space mission.

7.  Japan is only the third nation after the United States and Russia to have attempted an interplanetary space mission.