How long does it take to die in space?

As an expert in the field of space medicine and human physiology, I can provide a detailed answer to your question. When considering the scenario of an astronaut without a suit exposed to the vacuum of space, several factors come into play that would affect the timeline of a person's survival. Here's a breakdown: 1. Oxygen Depletion: The human body carries a certain amount of oxygen in the bloodstream and alveoli of the lungs. Without a suit, an astronaut would have about 15 seconds of consciousness before the oxygen in the bloodstream is depleted, leading to unconsciousness. This is a critical point, as the lack of oxygen to the brain is the primary immediate threat. 2. Pressure Difference: The pressure difference between the human body and the vacuum of space can cause the body's gases to form bubbles, which can lead to a condition known as decompression sickness or "the bends." However, the body's tissues are also elastic and can expand to some extent without causing immediate harm. 3. Temperature Extremes: Space is extremely cold, but the vacuum does not conduct heat away from the body quickly. An astronaut would not freeze instantly but could suffer from heat loss over time, especially if exposed to direct sunlight or shaded areas. 4. Acute Radiation Exposure: Without the protection of a space suit or a spacecraft, an astronaut would be exposed to high levels of radiation from the sun and cosmic rays. This could lead to radiation sickness and increase the risk of cancer. 5. Asphyxiation: After losing consciousness, the astronaut would not be able to breathe due to the lack of air pressure. The body would continue to use up the remaining oxygen in the body, leading to asphyxiation. Considering these factors, an astronaut without a suit in space would likely lose consciousness after about 15 seconds due to oxygen depletion. After losing consciousness, the body would eventually succumb to asphyxiation, though the exact time frame for this is less clear and would depend on the individual's health and the specific conditions of exposure.

At most, an astronaut without a suit would last about 15 seconds before losing conciousness from lack of oxygen. (That's how long it would take the body to use up the oxygen left in the blood.) Of course, on Earth, you could hold your breath for several minutes without passing out.