It is hard to imagine that making bubbles could be anything more than a fun and innocent childhood activity. When you think of bubbles, the first thing to pop into your mind may be a line of kids running across a field with bottles of soapy water, outstretched arms, and laughter. Yet, in a much different context (i.e. the vacuum of space), making bubbles is a dangerous process that can occur in the body and can lead to a condition known as decompression sickness.
Before learning about decompression sickness (DCS) in outer space, let us view it in a more familiar context here on Earth: scuba diving. As a scuba diver descends further and further below the surface of the water, the pressure rises around them[1]. This increase in pressure occurs because the deeper one goes, the “more” water is on top of them. It turns out that as pressure increases, the scuba diver breathes in more air molecules than they typically do because high pressures cause the air to be compressed. The additional oxygen from this extra air can be used by the body, but the additional nitrogen molecules in the air accumulate in the body [2]. The high pressure essentially allows for the nitrogen molecules to become dissolved, but that changes when the scuba diver returns to the surface [3]. As the diver ascends and the pressure decreases, the nitrogen will try to escape their body, and whatever is not expired ends up turning into nitrogen bubbles inside the body [2],[3].These bubbles are dangerous, as they can cause inflammation that leads to pain in muscles/joints and even obstruct blood vessels [2]. In the case of a diver experiencing DCS, one treatment option is hyperbaric oxygen therapy through a hyperbaric chamber. Essentially, in this treatment option, the affected person will sit in a chamber at a high initial pressure and the pressure will gradually decrease (allowing the nitrogen to freely exit the body rather than forming bubbles) [1].
The effects of DCS are not merely restricted to diving. Space is a very low-pressure environment, so special concerns related to DCS must be taken into account by astronauts. The pressure of the International Space Station (ISS) is 14.7 psi, which is about the same atmospheric pressure experienced at sea level on Earth. So if an astronaut has to exit the ISS in order to participate in extravehicular activity, there would be a drop in pressure [4]. To counteract the negative effects this may have, prior to leaving for their spacewalk, astronauts undergo a special breathing regimen consisting of 100% oxygen [4]. This prevents nitrogen gas from forming bubbles in the body since, hypothetically, there would be no nitrogen gas in the body. Such a measure is important as it helps prevent astronauts from having to experience DCS in space.
Pressure really can affect the body extensively, especially in the context of DCS. Thankfully, there are methods and interventions to help prevent and alleviate issues arising from it. So, the next time you see children playing with bubbles, don’t forget how bubbles can turn out to be harmful to the body. You can pass on telling them about it though; they’re probably not in any high pressure stakes at the moment.
References
Healthwise staff. U of M Health. https://www.uofmhealth.org/health-library/abo0894 (accessed February 2022).
Moon, Richard E. Merck Manual Consumer Version. https://www.merckmanuals.com/home/injuries-and-poisoning/diving-and-compressed-air-injuries/decompression-sickness (accessed February 2022)
Cooper, Jeffrey S.; Hanson, Kenneth C. Decompression Sickness. In StatPearls; StatPearls Publishing; Treasure Island (FL), updated 2021. https://www.ncbi.nlm.nih.gov/books/NBK537264/ (accessed February 2022)
Canadian Space Agency. https://www.asc-csa.gc.ca/eng/astronauts/space-medicine/decomp.asp (accessed February 2022)
NASA-Imagery / 29 images. Pixabay. https://pixabay.com/photos/space-walk-astronaut-nasa-aerospace-991/ (accessed February 2022)