Notes and summary: colonising space and gravity

Notes

Title: Difficulties of colonising space

1. Main claim: colonising space is harder than imagined
2. Nervous system
   • Children born in space may have permanent nervous-system damage unless exposed to Earth-like gravity at key stages
   • Trouble learning to walk on Earth (low-gravity development); adults may also struggle to readjust
3. Gravity and development
   • Gravity affects cell metabolism, brain development, DNA synthesis
   • Pregnant women cannot go to space
   • Mice study: 18 pregnant mice, ~200 foetuses; development and cell reproduction slowed; smaller brains, fewer nerve cells
4. Muscle wasting
   • Seen in astronauts; cause unclear (gravity on muscle cells or lack of use)
   • Strength loss temporary; no confirmed long-term illness
5. Conclusion: more study of gravity needed before people are sent to colonise space

Summary

Colonising space may be harder than expected because gravity is vital to human development. Children born in space may suffer permanent nervous-system damage and may be unable to walk properly on Earth, while adults may find it hard to readjust. Gravity also affects cell metabolism, brain development and DNA synthesis; in experiments, mouse foetuses grown in space developed more slowly and had smaller brains. Astronauts suffer muscle wasting, though it seems temporary. Further study is therefore needed before people are sent to colonise space.

(About 95 words.)