The objection identifies a real physical difficulty only if Jesus' ascent is assumed to occur by ordinary human means. The Quran, however, presents it as an act of divine deliverance, so the argument does not show a contradiction; it shows that the event is miraculous.
The objection stated fairly
The strongest form of the objection is this: a living human body cannot simply rise through the atmosphere into space. As altitude increases, oxygen and air pressure fall, and an unprotected person would lose consciousness and die. Therefore, if the Quran means that Jesus was physically alive when Allah raised him, the account appears biologically impossible. The Muslim is then said to face a choice: accept that Jesus really died, contrary to the Quran, or appeal to a miracle that the text does not explain.
What the Quran actually says
They did not kill him, nor did they crucify him, but it was made to appear so to them... Rather, Allah raised him up to Himself. And Allah is Almighty, All-Wise.
Quran 4:157-158
The passage directly denies that Jesus was killed by his enemies and contrasts their failure with Allah's act of raising him. The mainstream interpretation of the early Muslim scholars is that this refers to a bodily raising while Jesus was alive. Later, authentic reports in Sahih al-Bukhari and Sahih Muslim speak of Jesus descending before the Last Day, reinforcing that understanding.
The verse does not describe the route, speed, altitude, atmospheric conditions, or biological mechanics of the event. Nor does it say that Jesus rose by the unaided power of an ordinary human body. It attributes the event to Allah. "To Himself" does not mean that Allah occupies a physical location; Allah is not contained by space. It means that Jesus was raised by divine command and protection, into Allah's care and honor.
Why this is not a logical contradiction
The objection quietly assumes that all events must follow the usual physical order. That assumption would rule out every miracle before examining the evidence for one. If Allah created the laws governing oxygen, pressure, and bodily life, He can preserve a person from their ordinary effects or remove him from the situation in an extraordinary manner. A miracle is not a claim that the normal process happened unaided; it is a claim that Allah acted beyond that process.
Calling this "unexplained" also needs precision. The Quran does not provide a scientific account of how Jesus was protected, but it does identify the agent and purpose: Allah rescued him from those who sought to kill him. Many events can be meaningfully affirmed without their mechanism being described.
What the argument does and does not establish
It establishes that a literal bodily ascension is not an ordinary physiological event. It does not establish that the event is logically incoherent, nor that the Quran contradicts itself. To refute the Islamic claim, one would need to show that divine preservation or miraculous raising is impossible, not merely that an unprotected ascent would be fatal.
The question therefore turns on whether one allows miracles and whether the Quran's testimony is trusted, not on a contradiction within the claim itself.