The masses of the objects and the distance between them
-hope it helps
Galactic is referring to the galaxy and cosmos! :)
Gamma radiation have the most penetrating power. It can penetrate through human body, aluminum and other metals. It can be stopped by lead. Hence, the radioactive waste are stored in lead container for safety purposes. The beta ray has more penetrating power than the alpha but less than gamma. The beta radiations can be stopped by aluminum. The alpha radiations have least penetrating power and it can be stopped by human hands.
Answer is: the atom is the smallest known particle of matter.
John Dalton claimed that atom is indestructible and a<span>ll atoms of a given element are identical in mass and properties.
</span>Thomson discovered electron and found the first evidence for isotopes<span> of a stable element.</span>