Astral Projection
You and up to eight willing creatures within range project your astral bodies into the Astral Plane (the spell ends instantly if you are already on that plane). Each target's body is left behind in a state of suspended animation; it has the Unconscious condition, doesn't need food or air, and doesn't age.
A target's astral form resembles its body in almost every way, replicating its game statistics and possessions. The principal difference is the addition of a silvery cord that trails from between the shoulder blades of the astral form. The cord fades from view after 1 foot. If the cord is cut—which happens only when an effect states that it does so—the target's body and astral form both die. A target's astral form can travel through the Astral Plane. The moment an astral form leaves that plane, the target's body and possessions travel along the silver cord, causing the target to re- enter its body on the new plane.
Any damage or other effects that apply to an astral form have no effect on the target's body and vice versa. If a target's body or astral form drops to 0 Hit Points, the spell ends for that target. The spell ends for all the targets if you take a Magic action to dismiss it. When the spell ends for a target who isn't dead, the target reappears in its body and exits the state of suspended animation.
Astral Projection 5e 2024 vs. 2014 edition differences
The 2024 version ends instantly if already on the plane, while 2014 does not specify this. The 2014 version states the spell is "Special" duration, while 2024 is "Until dispelled." The 2014 version specifies the silver cord fades after 1 foot, while 2024 states it fades from view after 1 foot. The 2014 version emphasizes the astral form's separation from damage, while 2024 states effects have no effect on the body and astral form separately. The 2014 version mentions the spell can end early via dispel or 0 HP, while 2024 states the spell ends if the cord is cut or if either form drops to 0 HP.