Lagrange-2 point,
1
Lange, Andrew,
1
Lawrence Berkeley Laboratory,
1
,
2
Leavitt, Henrietta,
1
Lemaître, Georges,
1
,
2
light
darkness at night,
1
speed of,
1
types,
1
wave/particle nature,
1
wavelengths and distance measurement,
1
,
2
wavelengths defined,
1
see also
cosmic background radiation
;
photons
;
spectra
light horizon, cosmic,
1
Local Cluster,
1
Lowell Observatory,
1
Lubin, Phil,
1