The panspermia hypothesis proposes that life exists throughout the universe and can be spread from one location to another via asteroids, comets, and meteorites. There are different types of proposed panspermia, including lithopanspermia between solar systems and ballistic panspermia within a solar system. The idea has a long history dating back to ancient Greek philosophers. Evidence includes bacteria and other microbes that can survive extreme conditions like space vacuums and some meteorites containing amino acids. If life on Earth originated through panspermia, the debate continues around where and how life first originated.

1. Panspermia
By: W.P.SASHIKA DILSHAN

2. How did life come in to
existence?
Based on which theory?
Panspermia!

3. What is the panspermia?
‘Panspermia’ – Greek word for “seeds
everywhere”
The panspermia hypothesis states that the
seeds of life exist all over the universe and
can be propagated through space from one
location to another.

4. According to this hypothesis, Seeds of life
travelling through
Asteroids cometsMeteorites

5. Types of panspermia hypothesis
Lithopanspermia-from one solar system to another
Ballistic panspermia- from one planet to another
within the same solar system
Directed panspermia-from Earth to other planets
by humans

6. History of panspermia hypothesis
1. The first known concept was written by Greek
philosopher Anaxagoras (500BC-428BC)- all things have
existed from the beginning.
2. In 1743 French natural historian Benoit de Maillet, who
believed “seeded” by germs from space into the ocean.
3. In 1973, Professor Francis Crick and Leslie Orgel
proposed directed panspermia hypothesis.

7. History of panspermia hypothesis…………….
4. In 2001, astronomer Chandra Wickramasinghe
presented evidence from samples of space
contained clumps of living cells and light rays from
the space.
5. In 2001, Geologist Bruno and molecular biologist
Giuseppe found bacteria inside a meteorite
estimated to be over 4.5 billions years old.
6. In 2008, Stephen Hawking discussed about life in
space

8. Evidences
Some microorganisms can survive in harsh
enviornment conditions
Ultra violet radiation
Proton bombardment
Cold temperature
High temperature
Extreme pressure
EVEN IN A VACCUM!
Tardigradees

9. Bacterial spores
can remain viable for up to 250 million years
Can able to survive in a vacuum
Many bacteria can be preserved in liquid
nitrogen at -196 ŸC

10. Some Meteorites contain
Amino acids
Protected carbon inside the rocks

11. Why this panspermia hypothesis
is important for us?

12. 1.Knowing history is always important for planning our future
2.If life came from space, there is a probability of civilized
earth like planets in space could exist.
3.If space have beneficial organisms, we can use them.
4.If they are dangerous, we can make solutions for avoid
them.

13. Question;
If life of earth was a result of
panspermia,
Where and how life originated

14. The debate is still
ongoing...

15. References:
Comets-a vehicle for panspermia
F.Hoyle, C.Wickramasinghe - Comets and the Origin of Life,
From panspermia to bioastronomy, the evolution of the hypothesis of
universal life
F.Raulin-Cerceau, MC Maurel, J.Schneider - … of Life and Evolution of
the …, 1998 – Springer
www.cambridge.org/core/journals/international-journal-of-
astrobiology/article/numerical-testbed-for-hypotheses-of-extraterrestrial-
life-and-intelligence

16. THANK YOU!