1. High School Teachers 2006

2. Questions to answer
How can we understand if what we see is a star or a planet?(or something else…..)
Can you imagine an easy way to find how far a star is from the earth?
Can you understand what the materials are in the star from that distance?
If there are stars like our sun is it possible to have planets like our planet? Are We Alone?

3. How can we understand if what we see is a star or a planet
How can we understand if what we see is a star or a planet?(or something else…..)
Planets
If we consider the Earth as the centre of the solar system then the sun and the planets are in the same plane.
So the planets during the night must be in the same trajectory as the sun in the day.
But…..
How can we distinguish the planets from the stars even in this narrow plane?

4. Stars
In the case of a planet the cone of light in the surface of the upper atmosphere is about a few hundred meters but in the case of a star is only a few cm. So the atmospheric turbulence may affect the image of the stars but not those of the planets. That is why the stars twinkle at night but the planets do not.

5. Can you imagine an easy way to find how far a star is from the earth?
practically
For the Sun
Intensity of light
Distance
For a star (like our sun)
We can imagine that a star looks like a light of 100W at a distance of 10Km
Intensity of light
Distance

6. Exact but only for near objects
Exact methods of finding distances
Exact but only for near objects
Parallax
Only for distances up to 200 light years
Star distance
Astronomical
unit =1AU r

7. Other methods…….. As far as we can see v =H D
Standard Candles
Example For this type of stars we can evaluate with great accuracy the absolute magnitude by change of the period of luminosity
Novae 6 million light years
Supernovae 30 million light years
Cepheid 60 million light years
Hubble's Law 1billion light years
v =H D

8. The analysis of light is a common phenomenon
Can you understand what the materials are in the star from that distance?
The analysis of light is a common phenomenon

9. Spectroscopy Continuous spectrum Emission spectrum Absorption spectrum
Hot gas
Emission spectrum
Cold gas
Absorption spectrum

10. Each element is responsible for a different set of absorption lines in the spectrum so the spectrum indentifies the element like the fingerprint indentifies the human.

11. Spectroscopy mechanism
Cold gas

12. The absorption spectrum of the sun

13. UFO Sightings Map: Western Hemisphere
If there are stars like our sun is it possible to
have planets like our planet? Are We Alone?
What is this;
UFO Sightings Map: Western Hemisphere
If you don’t believe….

14. MATHEMATIC CALCULATION
THEORIES
panspermia
Exogenesis
MATHEMATIC CALCULATION
DRAKE EQUATION
N is the number of civilizations in our galaxy with which we might expect to be able to communicate at any given time and
R* is the rate of star formation in our galaxy
fp is the fraction of those stars that have planets
ne is average number of planets that can potentially support life per star
fl is the fraction of the above that actually go on to develop life
fi is the fraction of the above that actually go on to develop intelligent life
fc is the fraction of the above that are willing and able to communicate
L is the expected lifetime of such a civilization
Current estimates of the Drake equation parameters N=0,000008

15. SETI (Search for Extra-Terrestrial Intelligence)
Direct search
Arecibo message
SETI (Search for Extra-Terrestrial Intelligence)

16. Multiple planet systems
OBSERVATIONS OF EXTRASOLAR PLANETS
Multiple planet systems
There are currently 45 known planets in 19 multiple planet systems
Single planet systems
There are currently 144 known planets in single-planet systems
GQ Lupi on 25 June 2004 with the adaptive optics instrument

17. MISSIONS FOR EXTRASOLAR PLANETS SEARCHING
NASA Kepler Mission (2008) ESA Darwin (2015)
Kepler spacecraft Darwin