On May 4, 1976, a spacecraft resembling a disco ball entered orbit almost 3,700 miles (6,000 kilometers) above Earth. This shiny, two‑foot‑wide (60‑centimeter) sphere called the Laser Geodynamics Satellite, or LAGEOS, is covered with 426 retroreflectors—small mirrored prisms designed to bounce laser light directly back to where it came from. Beneath its aluminum exterior sits […]
Posted on
May 4, 2026
Sign up for our newsletter:
Categories
10
11
4
1
7
51
613
24
287
140
13
6
1
23
3
2
2
18
1
2
1
253
52
31
1
3
13
340
15
117
1
10
1
1
6
1
4
10
4
215
12
2
1
11
1
29
1
26
15
166
1
188
1
1
9
1
4
2
15
1
6
93
2
8
3
50
3
3
2
14
1
1
1
41
205
1
10
131
6
18
29
17
1
2
4
149
3
377
3
1
25
31
1
1
2
25
64
37
18
1
18
81
1
29
41
10
20
15
4
43
6
2
1
349
2
14
102
1
42
1
6
153
100
1
1
16
4
101
1
1
3
38
10
2
57
1
3
3
189
133
1
10
9
1
1
11
5
6
10
3
1
11
35
22
2
5
9
1
5
40
2
2
1
330
2
4
336
12
20
1
25
1
1
106
1
3
1
2
14
1