Are we Alone? - The Search for Life beyond the Earth.

Professor Ian MorisonJodrell Bank Observatory

and Gresham College

Star-stuff

Ring Nebula

M1

The Crab Nebula

Elsewhere in our own Solar System

We could find other simple life-forms here.

Canals on Mars?

The Face on Mars!

Valleys and Volcanoes

Olympus Mons

Islands and Channels

Rivulets

4,000 Million Years ago

Viking on Mars

• Two Viking Spacecraft landed on Mars in 1976 to search for evidence of life.

Spirit and Opportunity

Beagle II would have looked for evidence of Life.

Lovell Telescope Observations• 25/26/27/28

December

• 23/24/25 January

• Whilst Beagle 2 landing site was visible from Jodrell Bank

Waterfall Display

Beagle II is found!

Phoenix Lander

Streaks down Canyon Walls

Salt Water Flow

Salt Water Flow

Extremophiles

Water at Boiling point

Grand Prismatic Spring Yellowstone Park

Jupiter

Io

Europa

Callisto

Ganymede

4 major moons – discovered by Galileo

Io

Jupiter’s Moon Europa

Breaking up of the surface

• Icebergs!

Water Plumes!

Searching for Life!

Finding Evidence of Simple Life on other Planets

Can we see any exo-planets?

A real problem due to the overwhelming brightness of the star

orbited by the planet.

Infrared observations by one of the KECK telescopes

HR 8799 with three planets

Indirect Detection Methods

The RADIAL VELOCITY or DOPPLER WOBBLE method

51 Pegasi b

• The first planet detected around a normal star.

• Period just 4 days!

• A gas giant very close to its star.

Planetary Transits Detect the transit of a

planet as it crosses the face of the star. This results in a slight drop in luminosity.

This can only work if the orbital plane of the planet includes the Earth.

HD 209458 transit

HD 209458 b• 150 light years

from Earth.• Planet orbits

every 3.5 days.• 4 million miles

from its star.• Atmospheric

temperature ~2000K.

The Kepler Mission

Kepler 22b

European Extremely Large Telescope

Evidence for Life?

We could detect evidence of life by observing the spectra of the planet’s

atmosphere.

Study the Infra-Red Spectrum

What does it tell us?

SETI

The Search for Extraterrestrial Intelligence

The Seminal Paper

• In 1959 Giuseppe Cocconi and Phillip Morrison published a paper in Nature in which they pointed out that given two telescopes of the size of the newly built 250ft Mk1 Radio Telescope at Jodrell Bank it would, in principle, be possible to communicate across inter-stellar distances.

Where to look? Locations• They suggested that any

search should target the nearest Sun-like stars as these live long enough and are hot enough to allow life a chance to evolve on a planet at a suitable distance from them.

• A target list was provided including TauCeti and Epsilon Eridani.

Where to look? Frequency• They pointed out that the background noise (atmosphere,

Galaxy, CMB etc.) was a minimum between ~1 to 10 GHz.

• This band included the (radio) Hydrogen Line at 1.4 GHz and the OH Lines at ~ 1.6 GHz.

• The band from 1.4 to 1.6 GHz is called the Water Hole

Project Ozma

• In 1960 Frank Drake and his colleagues at Green Bank, West Virginia, used the Tatel 85ft telescope to make the very first SETI observations in what was called Project Ozma.

Project Ozma

• They were given use of a new, state of art, low noise parametric amplifier and made observations over a 400 KHz band around the Hydrogen Line at 1420 MHz.

• They observed Tau Ceti and Epsilon Eridani for a total of two months, but only detected the, then top secret, U2 Spy plane!

The Wow! Signal• In 1977 the Ohio State University Big Ear radio

telescope, which had been making SETI observations since 1973, detected a possible ET signal - so strong that the observer wrote Wow ! in the margin of the data printout. The changing strength of the signal perfectly matched the beam pattern of the telescope indicating that its source was at great distance. No real explanation exists, even today.

Recent and on-going searches

SETI at Berkeley• Project SERENDIP ( Search for Extraterrestrial Radio

Emissions from Nearby Developed Intelligent Populations!) is operated by The University of California at Berkeley. The experiment rides “piggyback” on the Arecibo 305m radio-telescope and has an 8M channel receiver.

SETI at NASA• The NASA SETI project developed a dual

telescope system for a targeted search, but funding was cut in 1993 soon after it began to operate using the 305m Arecibo Telescope.

• This project was being managed by the SETI Institute.

• The SETI Institute then took over the receiver systems and carryied on the targeted search using private funding in what was called Project Phoenix.

In 1998 a major upgrade to the Arecibo Telescope was completed and plans were made to use it again. It needs a large associated antenna to allow it to use it’s full sensitivity. The Lovell Telescope was ideal!

Their equipment was installed at Jodrell Bank in June 1998 and the first observations made in September.

820 sun-like stars observed out to ~200 light-years.

Pioneer 10 (R.I.P)• Pioneer 10 is now 7 Billion miles from us, well beyond

Pluto. We used it to prove that the system is fully operational during each observing session.

The SETI Institute’s Allen Telescope Array

Has received new funding

Sadly ET has not phoned home.

Should we be surprised?

New SETI Programs

$100 million dollar program over 10 years funded by Yuri Milner, a

Russian Oligarch

The Green Bank Telescope

The Parkes Telescope

Optical SETI at Harvard

New Optical SETI programme using the 2.4m Automated Planet Finder Telescope

The Square Kilometre Array

A giant radio telescope whose global headquarters will be at Jodrell Bank

Observatory.

Central Core

Role in SETI

• The SKA will, for the first time, have a realistic chance of searching the whole of the Milky Way Galaxy for evidence of intelligent life.

Would a civilisation attempt to communicate with us?

How does what we have learnt about other planetary systems affect the

likelyhood of other life being present in our galaxy?

Fraction of Sun-type stars• ~73-84% of the stars in

the Milky Way are M type – too cool

• Upper limit of 21% of stars in the Milky Way are like our Sun.

Fraction of Sun-type Stars with Planets

• We do not yet know.

• As time goes by we will be able to detect many more.

• There may be 10-30% of stars with planetary systems.

Fraction of stars with terrestrial planets within their solar systems

• Again we do not know – but we are finding many solar systems where we do NOT believe there can be Earth-Like planets.

• Hopefully this is because solar systems like ours are rather hard to find!

Number of Planets in a Star’s Habitable Zone

• 8 planets; many satellites• Earth, Mars; (Europa)

Found!

Fraction of habitable planets where life arises

• Wild optimism: the fraction where life arises = 100%

Simple Life could be very common.

How often will simple life evolve into intelligent life?

This, in my view is the most difficult part of this equation to estimate.

• Our Moon has stabilised our rotation axis

Plate Tectonics

• Recycles CO2 back into the atmosphere

COMETS

Fraction inhabited by intelligent beings

• One needs, we believe, a very long time to allow life to evolve.

• It is really difficult to estimate how often a planet will have a temperate climate for long enough.

Perhaps our human race is rather special.

A book based on my Gresham Lectures in London

As Patrick Moore would say:“We just don’t know”

• But this means that we cannot say that there are not other communicating civilisations.

The Future of Radio SETI

Where should it be sited?

Should we have detected ET yet?

• Only two searches – SERENDIP and Phoenix have had decent sensitivity.– SERENDIP could detect an airport radar at 10

light years, Phoenix at ~ 200• These have had limited coverage

– SERENDIP ~ 30% of sky– Phoenix ~ 800 stars

• But our galaxy is 100,000 light years across!

Should we continue to search for signals from ET?

As Giuseppi Cocconi and Phillip Morrison concluded their paper in 1959:

“the probability of success is difficult to estimate, but if we never search, the

chance of success is zero.”