1
00:00:02,000 --> 00:00:04,000
This is the ESOcast!

2
00:00:04,260 --> 00:00:07,890
Cutting-edge science and life behind the scenes of ESO,

3
00:00:07,890 --> 00:00:10,310
the European Southern Observatory,

4
00:00:10,500 --> 00:00:17,980
exploring the ultimate frontier with our host Dr J, a.k.a. Dr Joe Liske.

5
00:00:20,000 --> 00:00:23,500
Hello and welcome to this special episode of the ESOcast.

6
00:00:23,500 --> 00:00:27,850
Leading up to ESO’s 50th anniversary in October 2012,

7
00:00:27,850 --> 00:00:30,630
we will showcase eight special features

8
00:00:30,630 --> 00:00:35,560
portraying ESO’s first 50 years of exploring the southern sky.

9
00:00:39,080 --> 00:00:43,000
Finding Life

10
00:00:45,500 --> 00:00:48,470
Have you ever wondered about life in the Universe?

11
00:00:48,470 --> 00:00:51,600
Inhabited planets orbiting distant stars?

12
00:00:51,600 --> 00:00:54,500
Astronomers have — for centuries.

13
00:00:54,500 --> 00:00:58,950
After all, with so many galaxies, and each with so many stars,

14
00:00:58,950 --> 00:01:01,140
how could the Earth be unique?

15
00:01:02,500 --> 00:01:07,110
In 1995, Swiss astronomers Michel Mayor and Didier Queloz

16
00:01:07,110 --> 00:01:11,660
were the first to discover an exoplanet orbiting a normal star.

17
00:01:12,000 --> 00:01:16,490
Since then, planet hunters have found many hundreds of alien worlds.

18
00:01:16,490 --> 00:01:21,780
Large and small, hot and cold, and in a wide variety of orbits.

19
00:01:22,600 --> 00:01:26,800
Now, we’re on the brink of discovering Earth’s twin sisters.

20
00:01:27,290 --> 00:01:33,290
And in the future: a planet with life — the Holy Grail of astrobiologists.

21
00:01:39,590 --> 00:01:43,070
The European Southern Observatory plays an important role

22
00:01:43,070 --> 00:01:45,310
in the search for exoplanets.

23
00:01:46,290 --> 00:01:50,560
Michel Mayor’s team found hundreds of them from Cerro La Silla,

24
00:01:50,560 --> 00:01:53,880
ESO’s first Chilean foothold.

25
00:01:54,890 --> 00:01:56,880
Here’s the CORALIE spectrograph,

26
00:01:56,880 --> 00:02:00,120
mounted on the Swiss Leonhard Euler Telescope.

27
00:02:02,030 --> 00:02:07,940
It measures the tiny wobbles of stars, caused by the gravity of orbiting planets.

28
00:02:07,940 --> 00:02:14,910
ESO’s venerable 3.6-metre telescope is also hunting for exoplanets.

29
00:02:16,200 --> 00:02:19,320
The HARPS spectrograph is the most accurate in the world.

30
00:02:19,320 --> 00:02:23,680
So far, it has discovered more than 150 planets.

31
00:02:28,750 --> 00:02:30,360
Its biggest trophy:

32
00:02:30,360 --> 00:02:36,950
a rich system containing at least five and maybe as many as seven alien worlds.

33
00:02:48,330 --> 00:02:50,960
But there are other ways to find exoplanets.

34
00:02:59,130 --> 00:03:05,350
In 2006, the 1.5-metre Danish telescope helped to discover a distant planet

35
00:03:05,350 --> 00:03:08,350
 that is just five times more massive than the Earth.

36
00:03:12,500 --> 00:03:16,200
The trick? Gravitational microlensing.

37
00:03:17,040 --> 00:03:22,150
The planet and its parent star passed in front of a brighter star in the background,

38
00:03:22,150 --> 00:03:24,320
magnifying its image.

39
00:03:26,420 --> 00:03:31,660
And in some cases, you can even capture exoplanets on camera.

40
00:03:34,960 --> 00:03:41,240
In 2004, NACO, the adaptive optics camera on the Very Large Telescope,

41
00:03:41,240 --> 00:03:45,220
took the first image ever of an exoplanet.

42
00:03:45,220 --> 00:03:51,020
The red dot in this image is a giant planet orbiting a brown dwarf star.

43
00:03:54,880 --> 00:03:59,650
In 2010, NACO went one step further.

44
00:04:01,440 --> 00:04:05,330
This star is 130 light-years away from Earth.

45
00:04:05,330 --> 00:04:12,080
It is younger and brighter than the Sun, and four planets circle around it in wide orbits.

46
00:04:13,900 --> 00:04:18,970
NACO’s eagle-eyed vision made it possible to measure the light of planet c

47
00:04:18,970 --> 00:04:23,490
—  a gas giant ten times more massive than Jupiter.

48
00:04:25,070 --> 00:04:27,450
Despite the glare of the parent star,

49
00:04:27,450 --> 00:04:31,450
the feeble light of the planet could be stretched out into a spectrum,

50
00:04:31,450 --> 00:04:34,380
revealing details about the atmosphere.

51
00:04:36,270 --> 00:04:42,740
Today, many exoplanets are discovered when they transit across their parent stars.

52
00:04:42,740 --> 00:04:46,020
If we happen to see the planet’s orbit edge-on,

53
00:04:46,020 --> 00:04:49,390
it will pass in front of its star every cycle.

54
00:04:49,390 --> 00:04:53,870
Thus, tiny, regular brightness dips in the light of a star

55
00:04:53,870 --> 00:04:57,310
betray the existence of an orbiting planet.

56
00:05:00,010 --> 00:05:04,600
The TRAPPIST telescope at La Silla will help search for these elusive transits.

57
00:05:05,250 --> 00:05:06,570
Meanwhile,

58
00:05:06,570 --> 00:05:13,120
 the Very Large Telescope has studied a transiting planet in exquisite detail.

59
00:05:13,910 --> 00:05:21,820
Meet GJ1214b, a super-Earth 2.6 times larger than our home planet.

60
00:05:24,010 --> 00:05:30,040
During transits, the planet’s atmosphere partly absorbs the light of the parent star.

61
00:05:34,200 --> 00:05:39,740
ESO’s sensitive FORS spectrograph revealed that GJ1214b

62
00:05:39,740 --> 00:05:44,000
might well be a hot and steamy sauna world.

63
00:05:46,920 --> 00:05:51,060
Gas giants and sauna worlds are inhospitable to life.

64
00:05:51,060 --> 00:05:54,060
But the hunt is not over yet.

65
00:05:55,010 --> 00:05:59,420
Soon, the new SPHERE instrument will be installed at the VLT.

66
00:05:59,420 --> 00:06:05,490
SPHERE will be able to spot faint planets in the glare of their host stars.

67
00:06:06,200 --> 00:06:12,140
In 2016, the ESPRESSO spectrograph will arrive at the VLT

68
00:06:12,140 --> 00:06:16,110
and greatly surpass the current HARPS instrument.

69
00:06:18,000 --> 00:06:21,850
And ESO’s Extremely Large Telescope, once completed,

70
00:06:21,850 --> 00:06:26,170
may well find evidence for alien biospheres.

71
00:06:33,480 --> 00:06:36,390
On Earth, life is abundant.

72
00:06:37,960 --> 00:06:46,640
Northern Chile offers its share of condors, vicuñas, vizcachas and giant cacti.

73
00:06:48,910 --> 00:06:53,830
Even the arid soil of the Atacama desert teems with hardy microbes.

74
00:06:57,970 --> 00:07:02,300
We’ve found the building blocks of life in interstellar space.

75
00:07:03,000 --> 00:07:05,790
We’ve learnt that planets are abundant.

76
00:07:10,110 --> 00:07:15,190
Billions of years ago, comets brought water and organic molecules to Earth.

77
00:07:17,540 --> 00:07:21,250
Wouldn’t we expect the same thing to happen elsewhere?

78
00:07:26,500 --> 00:07:28,400
Or are we alone?

79
00:07:30,040 --> 00:07:32,080
It’s the biggest question ever.

80
00:07:33,480 --> 00:07:36,530
And the answer is almost within reach.

81
00:07:46,000 --> 00:07:49,990
This is Dr J, signing off from this special episode of the ESOcast.

82
00:07:49,990 --> 00:07:53,260
Join me again next time for another cosmic adventure.

83
00:07:55,730 --> 00:07:57,500
ESOcast is produced by ESO,

84
00:07:57,500 --> 00:07:59,300
the European Southern Observatory.

85
00:07:59,300 --> 00:08:01,500
ESO, the European Southern Observatory,

86
00:08:01,500 --> 00:08:03,000
is the pre-eminent intergovernmental science and technology organisation in astronomy.

87
00:08:03,000 --> 00:08:05,000
Among both ground- and space-based observatories, ESO is the most productive observatory in the world.

88
00:08:08,350 --> 00:08:13,240
Transcription by ESO; translation by —