Scientists in the US have proposed a fascinating - if terrifying - new theory on what happens to us after we die.
Researchers at New York University's Langone School of Medicine have claimed that the mind continues to be aware of what is happening around it - even when the body has stopped showing any signs of life.
Theoretically, this means that we may be able to hear our time of death being announced by doctors.
In order to arrive at the theory, researchers led by Dr Sam Parnia, director of critical care and resuscitation research at Langone, have been studying people who technically died after suffering a heart attack - only to be revived later.
Speaking to Live Science, Dr Parnia said some of those involved in the study were aware of full conversations going on around them after their heart had stopped and they were pronounced dead.
Their accounts of those conversations were then verified by the nursing staff who were present during their "death."
"They'll describe watching doctors and nurses working; they'll describe having awareness of full conversations; of visual things that were going on, that would otherwise not be known to them," he said.
He said death is generally defined as the moment at which blood flow to the brain is cut off.
"Technically speaking, that is how you get the time of death," he said. "It is all based on the moment when the heart stops."
“Once that happens, blood no longer circulates to the brain, which means brain function halts almost instantaneously.
“You lose all your brain stem reflexes; your gag reflex, your pupil reflex - all of that is gone.”
He said the "thinking part" of the brain - the cerebral cortex - begins to slow down the moment the heart stops and flatlines within two to 20 seconds.
Brain cells then experience a chain reaction of processes that eventually result in their death - although this can take hours to occur.
In 2013, researchers at the University of Michigan found that animals experience a surge in brain activity in the minutes after death.
Through studying the electrical signals inside the brains of nine anaesthetised rats who were having induced heart attacks, researchers saw patterns that are linked to a “hyper-alerted state” in the brief period after clinical death.
Dr Parnia said his team was trying to understand exactly what people experience when they die, "because we understand that this is going to reflect the universal experience we're all going to have."