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Destination Tomorrow - DT15 - Titan

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Subido el 28 de mayo de 2007 por EducaMadrid

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NASA Destination Tomorrow Segment exploring a newly discovered moon called Titan that revolves around the planet Saturn.

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Hello everyone, I'm Brad Breckenridge, filling in for Steel McGonagall. 00:00:00
And I'm Kara O'Brien. 00:00:07
Welcome to Destination Tomorrow. 00:00:08
This program will uncover how past, present, and future research is creating today's knowledge 00:00:11
to answer the questions and solve the challenges of tomorrow. 00:00:16
We begin with a look at a fascinating moon called Titan, which is orbiting around the 00:00:19
planet Saturn. 00:00:23
This moon has become the subject of much scientific speculation in recent years, since it was 00:00:25
discovered to have an atmosphere roughly four times thicker than Earth's. 00:00:29
About half the size of Earth, this small planet-like moon has an atmosphere that contains large 00:00:34
amounts of nitrogen and carbon. 00:00:39
This is important because these chemicals are considered by many scientists to be the 00:00:41
building blocks for life as we know it. 00:00:45
Little is known about Titan's surface because its thick atmosphere hides it from view. 00:00:48
To help us learn more about Titan, NASA scientists have launched an intriguing mission to explore 00:00:53
this distant moon. 00:00:58
This mission, called Cassini-Huygens, was launched from Kennedy Space Center on October 00:00:59
15, 1997. 00:01:03
Once at Saturn, the Cassini-Huygens spacecraft will not only study Saturn's atmosphere and 00:01:06
its other moons, but will also drop a small lander onto the surface of Titan. 00:01:10
While Cassini-Huygens will dramatically boost our knowledge of Titan, it will likely lead 00:01:16
to more questions about this interesting moon. 00:01:20
Tonya St. Romain spoke with researcher Dr. Marianne Rudisill to find out more about the 00:01:24
current mission and possible future missions to Titan. 00:01:29
One of NASA's stated goals is to search for life and life-enabling conditions such as 00:01:36
water and lifelike chemistry throughout the universe. 00:01:41
In recent years, the task of searching for life has become much easier with the development 00:01:45
of tools like the Hubble Space Telescope and advanced sensors aboard spacecraft. 00:01:49
With these technology advancements, NASA scientists are now able to better identify 00:01:54
so-called hotspot locations in the universe. 00:01:59
A hotspot location is simply a celestial body, that is, a planet or a moon, that may have 00:02:02
conditions that are conducive to the origin and existence of life. 00:02:08
Scientists have located a number of potential hotspots in our solar system, though one of 00:02:12
the most intriguing is a moon orbiting the planet Saturn named Titan. 00:02:17
Titan is very exciting because unlike most moons in our solar system, it actually has 00:02:22
an atmosphere. 00:02:27
In fact, many scientists believe that Titan's atmosphere closely resembles early Earth's 00:02:28
atmosphere three and a half billion years ago, when life was just beginning on our planet. 00:02:34
The chemicals that make up Titan's thick, hazy atmosphere include nitrogen and carbon, 00:02:40
elements considered by scientists to be the building blocks or raw materials for life 00:02:45
as we know it. 00:02:50
With this in mind, NASA and European Space Agency scientists are working on a mission 00:02:51
called Cassini-Huygens, which will study Saturn and some of its moons, including Titan. 00:02:56
The Huygens probe will descend into the thick Titan atmosphere to study its composition 00:03:02
and look for signs of prebiotic chemistry. 00:03:07
I spoke with Dr. Marianne Rotesel at NASA Langley Research Center to find out why this 00:03:10
distant moon is such an important place to study. 00:03:15
Titan's a really interesting place to explore for a number of reasons. 00:03:18
It's a very large moon. 00:03:21
It's larger than two of our planets, Mercury and Pluto, but the most interesting thing 00:03:22
about it actually is that Titan has a very dense atmosphere, and this atmosphere has 00:03:27
a lot of chemistry, interesting chemistry going on. 00:03:32
Most of the atmosphere at Titan is nitrogen, a lot like Earth's. 00:03:36
It has methane, but it also has a lot of complex organic types of molecules going on, and it 00:03:40
has weather as well. 00:03:48
We think that potentially there are actually clouds on Titan that kind of rain organic 00:03:49
molecules down onto the surface and kind of lay out an organic sludge along the surface 00:03:56
of Titan. 00:04:01
A lot of scientists believe that in some important ways, Titan might actually be very much like 00:04:03
what Earth was like in its early days prior to life on our planet, so it's an interesting 00:04:10
place to go to kind of look at those processes and understand how life originated on our 00:04:15
planet in that type of physical environment. 00:04:20
One of the reasons Titan is of great interest to scientists is because it's the only moon 00:04:23
in the solar system known to have clouds and a thick, planet-like atmosphere. 00:04:27
Because Titan's atmosphere contains nitrogen and high percentages of smog-like chemicals 00:04:32
such as methane and ethane, it may actually rain gasoline-like liquids onto the surface, 00:04:37
forming shallow, methane-filled lakes. 00:04:43
Although the smog-like atmosphere would be harmful to humans and other forms of complex 00:04:46
life on our planet, the organic nature of Titan's atmosphere is much like the prebiotic 00:04:50
environment from which life arose here on Earth. 00:04:56
Simply put, these conditions may actually be laying the foundation for life on Titan 00:04:59
sometime in the future. 00:05:04
Dr. O'Donnell, is there potential for life on Titan? 00:05:05
Well, that's a really interesting question, actually, and maybe yes and maybe no. 00:05:09
And I say that because of this. 00:05:14
Maybe yes, because Titan has, as I said, some really interesting and complex organic chemistry 00:05:16
going on. 00:05:21
But the problem is that chemistry isn't all that it takes to have life. 00:05:22
Titan is very far away from our sun, and so it's a very, very cold place. 00:05:28
So the problem is that everything is ice. 00:05:32
And life, as we know, it needs access to liquid water. 00:05:35
And it also needs a source of energy. 00:05:39
So on the one hand, yes, the chemistry could potentially support early life on Titan, but 00:05:43
it's not warm enough. 00:05:50
It's too cold, and it doesn't have access to water and energy that it would need. 00:05:51
But you could speculate about some other ways, perhaps, that it could have liquid water. 00:05:56
We know, for example, that meteorites have come to Titan and hit the surface, generating 00:06:02
heat and bringing energy with it. 00:06:08
And perhaps for certain amounts of time, then that would mean that there could be pools 00:06:10
of liquid water there. 00:06:13
So it's really interesting to think about and speculate about the possibility of life 00:06:14
in other parts and other locations of our solar system. 00:06:18
And Titan is a very interesting place to look into those questions, and that's why we're 00:06:22
going there. 00:06:26
Once the spacecraft gets to Saturn, how will it collect data? 00:06:27
Will it use rovers like the Mars rovers? 00:06:30
No, actually, it's going to be rather different from the Mars mission. 00:06:32
We're not sending rovers like Spirit and Opportunity. 00:06:36
It won't be trundling around on the surface like we did on Mars. 00:06:39
First, we're sending the Cassini spacecraft, and it's an orbiter. 00:06:43
And when it reaches Saturn, it'll actually spend the next four years there kind of doing 00:06:47
a grand tour through a Saturn system. 00:06:52
And one of the things it will do is about 40 flybys near Titan and collect information, 00:06:57
kind of a big-picture view of Titan. 00:07:04
But then in addition to that, we have a Titan probe, Sliggen's probe, and that was developed 00:07:06
by the European Space Agency. 00:07:12
And it'll drop down through Titan's dense atmosphere, and all the way down, the instruments 00:07:13
will be taking all kinds of measurements like the density of the atmosphere and the temperature 00:07:19
and altitude and things of that sort. 00:07:25
And of course, it's going to be taking a lot of data, a lot of information about the chemistry 00:07:27
of Titan's atmosphere, what kinds of things are there and how much. 00:07:33
And it'll take about two to two and a half hours to get all the way down through a dense 00:07:37
atmosphere. 00:07:41
We don't know what it will land in, but it will be able to stay on the surface and then 00:07:42
in its local area kind of take some measurements and also radio that information back to the 00:07:47
orbiter and back to Earth. 00:07:52
The next generation of science missions to Titan will probably be much different than 00:07:56
the missions of today. 00:08:01
Because little is known about the moon's geology, one type of mission concept recently developed 00:08:03
by NASA would rely on a dirigible-type craft to move through Titan's atmosphere, taking 00:08:08
multiple measurements over time. 00:08:13
This blimp would float above the surface and deploy a small probe to sample Titan's atmosphere, 00:08:15
methane crater lakes, and crater rim ice. 00:08:21
The probe would be able to analyze the samples on the spot and then relay the information 00:08:25
to scientists back on Earth. 00:08:29
With Earth nearly 800 million miles away, the probe would need to be almost completely 00:08:31
autonomous. 00:08:36
This type of craft could conceivably float through Titan's atmosphere for many months, 00:08:48
gathering valuable evidence about Titan's chemistry and geology and what that means 00:08:52
for us back on Earth. 00:08:57
NASA Jet Propulsion Laboratory, California Institute of Technology 00:09:22
Realistically, what are your expectations? 00:09:53
Are you expecting to find life on Titan? 00:09:56
Scientists try to be very objective, you know, and only have attitudes and opinions based 00:09:59
upon what we know, of course. 00:10:04
And so I think a lot of people are holding back and saying, I don't expect to find life 00:10:06
there. 00:10:12
It's too cold. 00:10:13
Even though we have extremophiles here on our planet that can live in very dry or very 00:10:14
cold conditions, it's really cold out there, you know, and there isn't liquid water. 00:10:18
So we're not expecting to see anything there. 00:10:23
But the nice thing would be is if we could find, I think a lot of people would be very, 00:10:25
very happy if we saw some serious complex organic chemistry going on. 00:10:30
Prebiotic, you know, clearly prebiotic chemistry would just be wonderful. 00:10:35
Going to other destinations in our solar system and then gathering this kind of information 00:10:40
can really help us understand how our planet formed and how life originated on our planet. 00:10:45
And these were really profound questions, not just to scientists, but to everyone. 00:10:54
And so I think it's really interesting and great that NASA can send spacecraft and gather 00:10:58
these kinds of data to help us answer those kinds of questions. 00:11:05
Many astrobiologists are skeptical as to whether life as we know it exists on Titan. 00:11:12
Although many of the building blocks for life are there, temperatures average a numbing 00:11:17
minus 290 degrees Fahrenheit. 00:11:21
However, Titan might provide a habitat for life if scattered sources of heat from geysers 00:11:24
or volcanoes are discovered. 00:11:29
Coming up, we'll find out how NASA has been using a technique called aerobraking to insert 00:11:31
spacecraft into extraplanetary orbits. 00:11:35
But first, did you know that Saturn's density is the lowest in the solar system? 00:11:38
Although Saturn has a diameter of about 75,000 miles, it's made up of primarily hydrogen 00:11:43
and helium gases. 00:11:48
The presence of these gases makes Saturn's specific gravity at about 0.7, less than that 00:11:50
of water. 00:11:55
In fact, Saturn's density is so low that if it were placed in an imaginary gigantic 00:11:56
bathtub, it would float. 00:12:01
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Idioma/s:
en
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Autor/es:
NASA LaRC Office of Education
Subido por:
EducaMadrid
Licencia:
Reconocimiento - No comercial - Sin obra derivada
Visualizaciones:
576
Fecha:
28 de mayo de 2007 - 17:05
Visibilidad:
Público
Enlace Relacionado:
NASAs center for distance learning
Duración:
12′ 05″
Relación de aspecto:
4:3 Hasta 2009 fue el estándar utilizado en la televisión PAL; muchas pantallas de ordenador y televisores usan este estándar, erróneamente llamado cuadrado, cuando en la realidad es rectangular o wide.
Resolución:
480x360 píxeles
Tamaño:
70.37 MBytes

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