Sublight Speed Reference Table

(Updated 12 November 2012)

Colloquial Term

Percent
of
Light

Velocity

Rate of Travel in Astronomical Units

Time Dilation

m/sec

kps

AU/Hour

AU/Day

AU/Month

Time
Dilation
Slowdown
Factor

Tau (τ)
Factor

Point Nine Nine Light

99.00%

296,794,533

296,795

7.14

171.41

5,217.3

7.088812050083

0.141

Point Nine Light

90.00%

269,813,212

269,813

6.49

155.83

4,743.0

2.294157338706

0.436

Point Eight Light

80.00%

239,833,966

239,834

5.77

138.52

4,216.0

1.666666666667

0.600

Point Seven Light

70.00%

209,854,721

209,855

5.05

121.2

3,689.0

1.400280084028

0.714

Point Six Light

60.00%

179,875,475

179,875

4.33

103.89

3,162.0

1.250000000000

0.800

Point Five Light

50.00%

149,896,229

149,896

3.61

86.57

2,635.0

1.154700538379

0.866

Point Four Light

40.00%

119,916,983

119,917

2.89

69.26

2,108.0

1.091089451180

0.917

Point Three Light

30.00%

89,937,737

89,938

2.16

51.94

1,581.0

1.048284836722

0.954

Point Two Light

20.00%

59,958,492

59,958

1.44

34.63

1,054.0

1.020620726160

0.980

Point One Light

10.00%

29,979,246

29,979

0.72

17.31

527.0

1.005037815259

0.995

Point Oh-Five Light

5.00%

14,989,623

14,990

0.36

8.66

263.5

1.001252348644

0.999

Point Oh Two Five Light

2.50%

7,494,811

7,495

0.18

4.33

131.75

1.000312646561

1.0~

Point Oh One Light

1.00%

2,997,925

2,998

0.07

1.73

52.7

1.000050003750

1.0~

--

0.50%

1,498,962

1,499

0.04

0.87

26.35

1.000012500234

1.0~

--

0.25%

749,481

749

--

0.43

13.17

1.000003125015

1.0~

--

0.10%

299,792

300

--

0.17

5.27

1.000000500000

1.0~

--

0.05%

149,896

150

--

0.087

2.63

1.000000125000

1.0~

Mars-Earth Reentry Speed
(Upper End)


21,336

21

--

0.012

0.38

1.000000002533

1.0~

Mars-Earth Reentry Speed
(Lower End)


15,240

15

--

0.009

0.27

1.000000001292

1.0~

Lunar-Reentry Speed


10,973

11

--

0.006

0.19

1.000000000670

1.0~

Earth LEO Speed


7,800

8

--

0.005

0.14

1.000000000338

1.0~