PCS 182 Lecture Notes - Lecture 4: H I Region, Rare Earth Hypothesis, Kardashev Scale

• School: Ryerson University
• Department: Physics
• Course: PCS 182
• Professor: Margaret Buckby

Document Summary

Inner regions contain more material denser : mo(cid:396)e (cid:396)adiatio(cid:374) . Recall the space-fa(cid:396)i(cid:374)g ta(cid:396)dig(cid:396)ades e(cid:454)posed to uv but unfazed: radiation might be beneficial. Would cause mutations and possibly speed up evolution: jupiter-sized exoplanets could gravitationally attract comets/ asteroids. Which endanger / impact smaller planets in same stellar system our jupiter protects us. Alien civilizations: genome: (cid:272)o(cid:373)plete he(cid:396)edita(cid:396)(cid:455) i(cid:374)fo e(cid:374)(cid:272)oded i(cid:374) dna . Or rna: chimps and human genomes are more than 98% identical, chimps are our nearest relatives, small percentage% difference in dna huge difference in intellect. Is alien culture and technology comprehensible: would they even notice us?, will they. Hyroxyl radical = oh: uv radiation photodissociates h20 o is a byproduct. Travel is very unlikely: cold neutral hydrogen clouds in space emit wavelength. Spin-flip of hydrogen: a = 21 cm, f= 1420 mhz. Fo(cid:396)(cid:272)es a(cid:374)d (cid:373)asses of all pla(cid:374)ets i(cid:374) the s(cid:455)ste(cid:373) and