Glen Langston: Chautauqua Signs of Life: Pre-biotic Chemistry New Discoveries with the NRAO 100m Diameter Green Bank Telescope (GBT) Glen Langston Astrobiology Review Green Bank Discoveries What Radio Astronomers Observe Future Directions NRAO

Glen Langston: Chautauqua Astrobiology Credit: Pascal Ehrenfreund

Glen Langston: Chautauqua Ingredients for Life

Glen Langston: Chautauqua Miller-Urey-Type Synthese (1953)

Glen Langston: Chautauqua “It must be admitted from the beginning that we do not know how life began. It is generally believed that a variety of processes led to the formation of simple organic compounds on the primitive Earth. These compounds were combined together to give more and more complex structures until one was formed that could be called living. No one should be satisfied with an explanation as general as this.” Miller & Orgel: The origin of life on Earth, 1974

Glen Langston: Chautauqua Background   Two groups of life origin theories: Terrestrial origin. Extraterrestrial origin. Planets are not isolated in terms of biology and exchange of organic material could occur between them.   Possibility for cosmic delivery of basic molecules: Amount of micrometeorites (from 50 to 500  m in size) – tons daily. Meteorite flux tons per day. Heavy bombardment in early Earth times more than present amount. High percentage of organic components in carbonaceous chondrites Credit: Natalia Gontareva

Glen Langston: Chautauqua Astronomical Life Cycle Credit: Ehrenfreund and Charnley

Glen Langston: Chautauqua % of the mass of the Galaxy Lifetime: years Site of star formation NGC 604 T ~ 10 K r ~ 10 6 H atoms per cm 3 Cosmic rays drive a rich ion-molecule chemistry supplemented by neutral-neutral processes organic molecules organic molecules Interstellar Clouds

Glen Langston: Chautauqua H 1 He O C N Ne Si Mg S Fe Na P Elemental abundances

Glen Langston: Chautauqua Astronomer’s Periodic Table Credit: Ben McCall

Glen Langston: Chautauqua Many organic molecules were first discovered in with the 43m telescope in Green Bank. These detections were a surprise. The experts thought interstellar space was too harsh for chemistry! FORMAMIDE FORMALDEHYDE FORMIC ACID CYANO- ACETYLENE METHANOL ACETALDEHYDE Molecular Discoveries: 43m

Glen Langston: Chautauqua Interstellar Molecules Credits: Pat Thaddeus, Al Wootten Galactic Chemistry: Carbon Rich Life on Earth: Carbon based Coincidence?

Glen Langston: Chautauqua Field of View SensitivityResolution

Glen Langston: Chautauqua Molecular Discoveries: 100m World’s most sensitive Telescope in frequency range 10 to 50 GHz Discovered new interstellar molecules, including propenal and propanal

Glen Langston: Chautauqua Sugars in Space Ethylene glycol was discovered in a massive interstellar cloud of dust and gas near the center of the Milky Way Galaxy. Ethylene glycol was discovered in a massive interstellar cloud of dust and gas near the center of the Milky Way Galaxy. Ethylene glycol (a 10-atom molecule made up of carbon, hydrogen, and oxygen) is one of the five largest molecules ever discovered in space. Ethylene glycol (a 10-atom molecule made up of carbon, hydrogen, and oxygen) is one of the five largest molecules ever discovered in space.

Glen Langston: Chautauqua Evidence of Astro-Chemistry

Glen Langston: Chautauqua What do Radio Astronomers Observe? There’s no Eye piece on a Radio Telescope… Astronomers measure signal strengths as a function of frequency. With enough observations and imagination, we can see the first steps in the formation of life.

Glen Langston: Chautauqua Intensity versus Frequency Intensity (Volts) Frequency (MHz)

Glen Langston: Chautauqua Fundamental Laws International Law: FM Broadcast (200 kHz steps) Physics Laws: Quantum Mechanics and Molecular Structure. (GBT observations of HC 5 N, HC 7 N and HC 9 N) Frequency (MHz) Intensity (Kelvin) Intensity (Volts) HC 5 N HC 7 N HC 9 N

Glen Langston: Chautauqua GBT: Cyanopolyynes + HC 13 N Cyanopolyynes are ideal molecules for radio astronomy: Simple Structure, easy to model.Simple Structure, easy to model. Large dipole moment, strong lines.Large dipole moment, strong lines. Simple spectra.Simple spectra. If detected, suggest more biologically relevant molecules are present HCN HC 7 N

Glen Langston: Chautauqua UV radiation field ~ 10 8 photons cm -2 s -1 photochemistry simple di- and triatomic species: CH, CN, C 2, HCN, C 2 H 3 …. Soot, PAHs, carbonaceous networks….. T ~ 10 to 100 K (-400 F)  ~ cm -3 Diffuse Interstellar Medium

GBT K-Band Ammonia Maps 15 KFPA NH 3 (1,1) Ammonia mapping of dark clouds Finn & Jackson 22 Glen Langston: Cambridge 2011 April 26

Compare NH 3 and Cyanopolyyenes Glen Langston: Chautauqua

Glen Langston: Chautauqua Cyanopolyyne Line Intensities With the GBT, observations that took many hours with the 43m, now take only minutes. Rarer, weaker, isotopic versions ( 13 C instead of 12 C) of the molecules can be discovered with the GBT.

Glen Langston: Chautauqua Weak lines: HC 7 N Isotopomers Comparison of HC 7 N molecule 13 C/ 12 C Isotopomers: Abundance Ratio 1/80 TMC-1 is nearby (140 pc from Earth), so 13 C/ 12 C abundance is expected to be similar that abundance ratio observed on Earth. (Galactic variation observed.) We share a common history with TMC-1!

Glen Langston: Chautauqua Future Directions Radio Astronomers detect (in seconds) the molecules critical for life Lower frequency (5 to 20 GHz) observations are critical for study of important large molecules. Need *many* simultaneous lines for weak detections