Interview
Of the Panspermia theories which one do you think is the most likely to explain the origin of life?
Firstly, none of the Panspermia theories have an answer to the origin of life in general, but rather life on Earth. But when discussing the origin of life on Earth, Ballistic Panspermia stands out.
Firstly, none of the Panspermia theories have an answer to the origin of life in general, but rather life on Earth. But when discussing the origin of life on Earth, Ballistic Panspermia stands out.
Of the Panspermia theories which one do you think is the most likely to explain the origin of life?
Firstly, none of the Panspermia theories have an answer to the origin of life in general, but rather life on Earth. But when discussing the origin of life on Earth, Ballistic Panspermia stands out.
What about Ballistic Panspermia makes it stand out from the rest of the Panspermia theories?
This theory stands out because there is much more supporting evidence, compared to other Panspermia theories. Much of the evidence supporting Ballistic Panspermia is in relation to meteorites travelling from Mars to Earth. At its current state, organisms cannot survive on the planet, as its surface is a “freeze dried desert bathed in ultra-violet radiation”(Davies Superbugs, http://leiwenwu.tripod.com/davies.htm). However geothermal heat could have melted the permafrost under the surface, to create reservoirs of liquid brine, similar to those beneath Earth’s surface, providing conditions for organisms to grow. These organisms may have survived underground and migrated to Mars surface. Eventually Mars atmosphere “leaked” and the temperatures became extreme, which would have resulted in the death of the organisms. These organisms may have fossilised and be laying on Mars surface. It is possible for these fossils to be transported to earth by meteorites.
World Renowned astrophysicist Stephan Hawking delivered a speech at George Washington University as part of NASA’s 50th Anniversary lecture series. In his speech he supports the colonization of the Moon and Mars, but more importantly comments on the possibility of finding evidence supporting Panspermia. He states that “Life could spread from planet to planet or from stellar system to stellar system carried on meteors”. He goes on to state that Earth was formed 4.6 billion years ago and that the earliest fossils
found are 3.5 billion years old. He explains that Earth would have been too hot during its first 500 million years and that life beginning after this time is short compared to the 10 billion year lifetime of an Earth-like planet. He concludes his comments on Panspermia suggesting “Panspermia or that the probability of life appearing independently is reasonably high”(Hawking,S., 2008, Why We Should Go Into Space, ).
Firstly, none of the Panspermia theories have an answer to the origin of life in general, but rather life on Earth. But when discussing the origin of life on Earth, Ballistic Panspermia stands out.
What about Ballistic Panspermia makes it stand out from the rest of the Panspermia theories?
This theory stands out because there is much more supporting evidence, compared to other Panspermia theories. Much of the evidence supporting Ballistic Panspermia is in relation to meteorites travelling from Mars to Earth. At its current state, organisms cannot survive on the planet, as its surface is a “freeze dried desert bathed in ultra-violet radiation”(Davies Superbugs, http://leiwenwu.tripod.com/davies.htm). However geothermal heat could have melted the permafrost under the surface, to create reservoirs of liquid brine, similar to those beneath Earth’s surface, providing conditions for organisms to grow. These organisms may have survived underground and migrated to Mars surface. Eventually Mars atmosphere “leaked” and the temperatures became extreme, which would have resulted in the death of the organisms. These organisms may have fossilised and be laying on Mars surface. It is possible for these fossils to be transported to earth by meteorites.
World Renowned astrophysicist Stephan Hawking delivered a speech at George Washington University as part of NASA’s 50th Anniversary lecture series. In his speech he supports the colonization of the Moon and Mars, but more importantly comments on the possibility of finding evidence supporting Panspermia. He states that “Life could spread from planet to planet or from stellar system to stellar system carried on meteors”. He goes on to state that Earth was formed 4.6 billion years ago and that the earliest fossils
found are 3.5 billion years old. He explains that Earth would have been too hot during its first 500 million years and that life beginning after this time is short compared to the 10 billion year lifetime of an Earth-like planet. He concludes his comments on Panspermia suggesting “Panspermia or that the probability of life appearing independently is reasonably high”(Hawking,S., 2008, Why We Should Go Into Space, ).
Do you know of any examples supporting Ballistic Panspermia?
In 1984 a team of scientists discovered a meteorite (ALH84001) that left Mars an estimated 15 million years ago. In 1996 the meteorite was shown to contain structures of terrestrial nanobacteria. Further tests revealed that amino acids and polycyclic aromatic hydrocarbons (PAH) were present on the meteorite, however this is not conclusive
as the material could have been formed while on earth(Ballistic Panspermia, h).
The Kuiper Belt is a region of the solar system that surrounds all of the planets in the solar system. The belt contains comets and meteorites that are thought to have originated from the formation of the solar system. It is thought that most comets are found in the Kuiper Belt. It is thought that these comets could have organisms contained within them that have survived in space and have landed on earth(Comet: Frozen Seeds of Life From Bejond The Solar System, ).
The Murchison Meteorite was discovered in Murchison, Australia in 1969. The meteorite studied and was found to contain more than 70 amino acids, 19 of which are found on Earth(2012, MARMET-Meteorites, ). This suggests that life could begin in Space and possibly with more variation.
In 1984 a team of scientists discovered a meteorite (ALH84001) that left Mars an estimated 15 million years ago. In 1996 the meteorite was shown to contain structures of terrestrial nanobacteria. Further tests revealed that amino acids and polycyclic aromatic hydrocarbons (PAH) were present on the meteorite, however this is not conclusive
as the material could have been formed while on earth(Ballistic Panspermia, h).
The Kuiper Belt is a region of the solar system that surrounds all of the planets in the solar system. The belt contains comets and meteorites that are thought to have originated from the formation of the solar system. It is thought that most comets are found in the Kuiper Belt. It is thought that these comets could have organisms contained within them that have survived in space and have landed on earth(Comet: Frozen Seeds of Life From Bejond The Solar System, ).
The Murchison Meteorite was discovered in Murchison, Australia in 1969. The meteorite studied and was found to contain more than 70 amino acids, 19 of which are found on Earth(2012, MARMET-Meteorites, ). This suggests that life could begin in Space and possibly with more variation.
Radiopanspermia is different to most of the other variations of Panspermia, do you think that it is possible?
For bacteria to survive in space, it would have to withstand intense Ultraviolet (UV) radiation and extreme temperatures. This would make Radiopanspermia an invalid theory because the “naked” individual cells would be immediately destroyed by the UV. There was an experiment done by Washington State University in which the experiment was to find whether radiopanspermia is
possible and if so, what conditions did it require. They concluded that the idea of radiopanspermia is valid if micro-organisms (bacteria and viruses) are“shielded inside grains whose material blocks significant UV radiation, and are ejected into space in the late stages of a star’s life”(Secker,J., 1995, ),. However the chances of this happening are very unlikely as the conditions are
soo particular.
For bacteria to survive in space, it would have to withstand intense Ultraviolet (UV) radiation and extreme temperatures. This would make Radiopanspermia an invalid theory because the “naked” individual cells would be immediately destroyed by the UV. There was an experiment done by Washington State University in which the experiment was to find whether radiopanspermia is
possible and if so, what conditions did it require. They concluded that the idea of radiopanspermia is valid if micro-organisms (bacteria and viruses) are“shielded inside grains whose material blocks significant UV radiation, and are ejected into space in the late stages of a star’s life”(Secker,J., 1995, ),. However the chances of this happening are very unlikely as the conditions are
soo particular.
What is your opinion on the possibility of Lithopanspermia?
The theory of Lithopanspermia is possible, however there is little evidence to support this theory. This theory would require the micro-organisms to survive; the “impact-ejection process” of leaving the planet of origin, travelling through space and successfully landing on a planet in another solar system. Researchers from Princeton University (New Jersey, America) and CAB (Centro de Astrobiologia in Spain) created an experiment in which they tested whether lithopanspermia was possible through a low-velocity process called“weak transfer”(Kelly,M.,2012, ). Weak Transfer occurs when solid materials move out of the orbit of one large object and into the orbit of another. From their results they concluded that the weak transfer mechanism makes Lithopanspermia a “viable” hypothesis because of the large quantities of solid material being exchanged between the planetary systems, as well as incorporating “timescales that could potentially allow the survivial or micro-organisms embedded in large boulders”. This theory is possible as a few meteorites that have landed on earth have contained amino acids not found on earth, and even possible fossils. |
The possibility of Directed Panspermia is one met with a lot of criticism, what is your opinion?
This theory is possible, however there is limited evidence supporting the theory. In their article Francis Crick and Leslie Orgel argued that if humans intentionally infected another planet and life was sustained and diversified, that the theory was possible(Crick, F. & Orgel, L., 1973, ). However this has not happened and is just another explanation for a theory with no plausible evidence. Most of the arguments raised are based on, if humans can do it why could it not have been done before? |
You have previously said that the Hydrothermal vents theory is a far more likely to be the origin of life rather than Panspermia,why?
The theory that the origin of life on Earth occurred at Hydrothermal Vents is far more likely because there is more evidence and it is widely supported. The theory has been criticised because of the high temperatures of the vents. At molecular level, the intense heat would make the molecules unstable and its chances of producing and sustaining life would be effected. To combat this, supporters of the theory claim that the reactions would take place in the area between the cold seawater and the hot water of the vents exceeding 572 degrees Fahrenheit. Further evidence supporting Hydrothermal Vents is the discovery of an entirely new ecosystem. These vents are spread throughout the world and are home to various different animals such as white crabs, octopuses, squat lobsters, plume worms and many more, However each different area of vents are dominated by different organisms. The Mid-Atlantic Ridge is dominated by alvinoccaridid shrimp, the East Scotia Ridge is dominated by yeti crab, while vents along the East Pacific Rise and Galapagos Rift are dominated by siboglinid tubeworms. This shows that “Hydrothermal vent communities show much more inter-regional diversity”(Chown, S.,2012, ). The ecosystems are particularly unique as many of the organisms are not heterotrophs are previously thoughts, but rather get their energy from Chemosynthesis. Chemosynthesis is when organisms extract its energy from chemicals. The chemicals such as hydrogen sulphide and manganese are then released by the heat of the Earth’s core. At the base of these vents are tiny single-celled bacteria and organisms called Archaea. These organisms survive by converting chemicals such as hydrogen sulphide, into energy. The Archaea are thought to be one of the oldest forms of life on Earth and are known to survive in the most extreme environments on Earth(Hydrothermal Vent Creatures, 2010). If one of the oldest life forms, that is also able to survive in extreme environments, is found on hydrothermal vents it is reasonable to suggest that early life-forms were formed from the vents. |
How are extremophiles related to the origin of life?
Extremophiles are organisms that can thrive in extreme environments that most organisms would not survive in. Extremophiles are very helpful when testing if organisms can survive in conditions similar to Mars and Space. When testing whether extremophiles can survive in Space or Mars like conditions, they are exposed to high amount of UV radiation. A recent study of the micro-organisms living in red rain in India was completed. They discovered that the micro-organisms had no DNA, were able to metabolize several different organic and inorganic materials and were able to grow at temperatures up to 300 degrees celcius. They concluded that due to the characteristics not being exhibited by any known terrestrial organisms, that they must be of extraterrestrial organisms, and that the red rain was due to cometary Panspermia(Louis, G. & Kumar,S., 2003).
Extremophiles are organisms that can thrive in extreme environments that most organisms would not survive in. Extremophiles are very helpful when testing if organisms can survive in conditions similar to Mars and Space. When testing whether extremophiles can survive in Space or Mars like conditions, they are exposed to high amount of UV radiation. A recent study of the micro-organisms living in red rain in India was completed. They discovered that the micro-organisms had no DNA, were able to metabolize several different organic and inorganic materials and were able to grow at temperatures up to 300 degrees celcius. They concluded that due to the characteristics not being exhibited by any known terrestrial organisms, that they must be of extraterrestrial organisms, and that the red rain was due to cometary Panspermia(Louis, G. & Kumar,S., 2003).