<Tr> <Th_colspan="2"> Observation data </Th> </Tr> <Tr> <Th> Type </Th> <Td> Sb, Sbc, or SB (rs) bc (barred spiral galaxy) </Td> </Tr> <Tr> <Th> Diameter </Th> <Td> 100--180 kly (31--55 kpc) </Td> </Tr> <Tr> <Th> Thickness of thin stellar disk </Th> <Td> ≈ 2 kly (0.6 kpc) </Td> </Tr>

Number of stars in the milky way nasa