HUNTING FOR ALIENS or COSMIC PURALISM ANEW.

The earliest writers dreamt of life on the planets in our solar system; the Aborigines have stories dating thousands of years about the Dreamtime and how we came from the stars. The satirist Lucian (120 – c185 AD) claims in “A True Story” to have visited the moon after his ship was caught in a whirlwind which sends them to the Moon: a place inhabited by beings at war with the people of the Sun over the colonisation of the Morning Star, Venus. The title of first science fiction writer is most likely his!

Lucian.                                                       H.G. Wells.

In more recent times we had HG Wells’ ‘War of the Worlds’ (1897) followed a few years later by the astronomer Percival Lowell’s canals on Mars (1906) – where he believed he saw artificial canals, going so far as to draw them – to the idea that Venus might contain dinosaurs we have always been desperate to find life “out there”.

Looking for life beyond Earth is one of the most fascinating, exciting and difficult things to do. Every time we think we might have found a clue a discovery comes along to challenge us.

Modern research looks for ‘bio-markers’; these are chemicals that could only be present as a result of life. Nothing has been found (so far!!) in the solar system so the search has broadened into he universe to the exo-planets, the worlds around distant stars.

How do you find which gasses are present in a world in another solar system? It seems that the size (diameter) of the planet plays a role in whether we can detect atmospheres; a recent report in the Astrophysical Journal (https://arxiv.org/abs/1704.05413) goes into more detail. According to Angelos Tsiaras, the lead author, “More than 3,000 exoplanets have been discovered but, so far, we’ve studied their atmospheres largely on an individual, case-by-case basis.”

exoplanets

Using the Hubble Space telescope researchers looked at the spectral profiles of 30 exoplanets and analysed them for the characteristic fingerprints of gases that might be present. About half had strongly detectable atmospheres. Most of the atmospheres detected show evidence for clouds. The two hottest planets, where temperatures exceed 1,700 degrees Celsius, appear to have clear skies, at least at high altitudes. Results for these two planets indicate that titanium oxide and vanadium oxide are present in addition to the water vapour features found in all 16 of the atmospheres analysed successfully.

It is not only ‘Hot Jupiters’ that have had their atmospheres analysed: in April 2017 it was announced that Gliese 1132b, a super-earth, (that is a planet with a diameter upto 40% greater than the Earth’s) atmosphere had been detected. This is a major step in detecting signs of life in more earth like planets. (https://arxiv.org/abs/1612.02425)

gliese 1132b

How do astronomers detect the atmospheres? Well as a planet passes in front (transits) its host star the light from the star dims slightly; the planet blocks some of the light and the atmosphere absorbs some of the star light. If the composition of the star’s atmosphere is already known, when the planet transits the star, the planet’s atmosphere absorbs some of the starlight and changes what chemicals we can see from the starlight. It Is then possible to work out the composition of the planet’s atmosphere by the effect it had on the starlight.

The chemicals that astronomers look for when seeking life are called ‘bio-markers.’ They include Oxygen and Methane, which tend to be the product of organic processes and a chemical known as Freon-40. This latter was hoped to be a good indicator but, like Lucian’s moon people or Lowell’s canals things are not what they seem.

ALMA and Rosetta Detect Freon-40 in Space

Organohalogen methyl chloride (Freon-40) discovered by ALMA around the infant stars in IRAS 16293-2422

Freon-40 (CH3Cl), also known as methyl chloride. is known as an organohalogen; these are compounds which on Earth are formed by organic processes. Organohalogens consist of halogens (the inert gasses of the periodic table), such as chlorine and fluorine, bonded with carbon and sometimes other elements. On Earth, these compounds are created by some biological processes — in organisms ranging from humans to fungi —  as well as by industrial processes such as the production of dyes and medical drugs.

The idea was if Freon-40 is formed naturally on or earth or through artificial means then its detection in an exo-planet’s atmosphere would be a very good indicator of life, however that hoped has been dashed as Observations made with the Atacama Large Millimeter/submillimeter Array (ALMA) and ESA’s Rosetta mission, have revealed the presence of Freon-40 in gas around both an infant star and a comet. The star lies 400 light years way, the comet is the famous 61/P Churyamov-Gerasimenko; this is the comet that saw the European Rosetta probe orbit it and send the little lander Philae to its surface.

This is the first ever detection of them in interstellar space.

IRAS 16293-2422 in the constellation of Ophiuchus

This chart shows the location of the Rho Ophiuchi star formation region in the constellation of Ophiuchus. The star Rho Ophiuchi, which gives the region its name, is marked with the Greek letter rho (ρ). The position of IRAS 16293-2422, a young binary star with similar mass to the Sun, is marked in red.

This may mean that astronomers have understood things the wrong way round; rather than being a marker for life perhaps it is a necessary constituent of the ‘primordial soup’ from which life arises:

“ALMA’s discovery of organohalogens in the interstellar medium also tells us something about the starting conditions for organic chemistry on planets. Such chemistry is an important step toward the origins of life,” adds Karin Öberg, a co-author on the study.

This isn’t the only chemical that ALMA has detected, other molecules of astrobiological interest found around young stars on scales where planets may be forming have precursors to sugars and amino acids.

The discovery of Freon-40 around Comet 67P strengthens the idea that what we see in the pre-biological chemistry of distant protostars may have been what we would have seen in our own Solar System. It would seem that young solar systems inherit some of their chemical characteristics from their parent star forming cloud and then from cometary impacts.

                     ALMA 

  ALMA the Atacama Large Millimeter/submillimetrer Array.

It just shows, that when you think you may be onto a clue the Universe has different ideas!

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September Night Sky.

sept17 sky

The sky at 00h on the 17th. September.

Full Moon: 6th. September. New Moon: 20th. September.

Autumnal Equinox: 22nd. September.

Mercury reaches greatest Western elongation on the 12th. meaning it rises shortly before the Sun. It is a reasonably bright magnitude -0.4. It will be low down at sunrise so you will need a clear Eastern horizon to see this elusive body. The thin crescent of the waning moon passes nearby on the 19th.

Above Mercury lie two other planets; Venus is a bright -3.9; the moon passes just south on the 18th. The moon also passes very close to the brightest star in Leo, Regulus, the same night. Mars lies between Mercury and Venus and is the faintest of the planets at magnitude 1.8.

Of the giant planets Saturn is the most easily visible; shining between magnitude +0.4 and +0.5 in Ophiuchus. The moon will pass just above it on the 26th and 27th. Saturn remains low in the sky and sets around 9:45 pm.

For more of a challenge why not try to find the distant planets nicknamed the ‘Ice Giants’? Uranus lies in Pisces and is just below naked eye visibility, at magnitude +5.7, but a pair of binoculars should show it as a round object. It is visible most of the night – rising at 7.20 pm by the end of the month.

Neptune will be visible for a week or so after the 6th. It is much feinter at magnitude +7.8 so will be more of a challenge. It is low in the sky in Aquarius. The ‘N’ on the map marks the approximate area in the sky to look next to the star λ Aquarii. The full moon is nearby on the 6th but is so bright it washes out the planet.

 

On This Day…

 

165 Years Ago – September 5th. 1857: Konstantin E. Tsiolkovsky, the father of rocketry was born in village of Izhevsk, in the USSR.

55 Years Ago – September 12th. 1962: President John F. Kennedy gives his famous address at Rice University on the nation’s space effort. In this well-known speech, Kennedy stated that we explore space not because it is easy but because it is difficult. This was the beginning of the journey to land men on the moon.

40 Years Ago – September 5th. 1977: Voyager 1was launched from Cape Canaveral on a Titan IIIE-Centaur launch vehicle. This was the beginning of the ‘Grand Tour’ of the planets.

September 29th. 1977: The USSR launched the Salyut-6 space station aboard Proton K rocket from Baikonur.

Tsiolkovsky                                     John F, Kennedy

Published in: on September 14, 2017 at 15:58  Leave a Comment  

Night Sky, August 2017

august sky

 

The night sky at 23h on the 14th. August.

Full Moon: 7th. August. New Moon: 21st. August.

August is a poor month for planets; Venus lies close to the star Pollux in Gemini and shines at a bright -3.9 in the early morning sky. As the month progresses though Venus begins to move towards the Sun making it harder to observe. The moon passes near Venus over the mornings of the 18th to the 20th.

Jupiter sets now a few hours after sunset and can be found low to the south-west near to the bright star Spica. The moon passes just above Jupiter on the 25th.

Saturn remains in the unremarkable constellation of Ophiuchus this month. It is to be found low in the west and is the brightest object in this part of the sky. The moon passes near to Saturn twice this month, on the 2nd and 30th of the month making a handy marker to the planet.

August sees the Perseid meteor shower, one of the best of the year. It lasts from July 17th until the 24th August and the peak display is usually around the 13th August. Unfortunately the moon is going to get in the way of seeing feinter meteors. To maximise your chances of seeing some meteors try and block street and house lights using walls and trees as shades. Look towards the north – after midnight is best but the moon will be in the way so may make things a bit trickier. The Perseids are made from the debris of comet Swift-Tuttle which was also known as the Great comet of 1862.

This month also sees a total eclipse of the Sun on the 21st. sadly this is only visible from the USA.

One of the most noticeable features in the Summer sky is the ‘Summer Triangle.’ This shape is not a constellation but is made from stars from three different constellations; Deneb in Cygnus, Vega in Lyra and Altair in Aquila. The term was first used by Patrick Moore. It can be found high overhead through out the month and is a handy way of finding three different constellations in one go!

 

On this Day…

 

55 years ago, 12th. August 1966 — In the first double flight (occurring at the same time as Vostok 3 with cosmonaut Nicolayev), the Soviet Union launched Vostok 4, with cosmonaut Papel Popovich.

11 years ago, 24th. August 2006 – The International Astronomical Union votes to approve a new definition of “planet” that excludes Pluto, leading to much upset and disagreement in the subsequent years! Pluto was re-classified as a dwarf planet.

5 years ago, 6th. August 2012 – The Mars rover Curiosity lands on the Red Planet as part of NASA’s Mars Science Laboratory mission.

pluto new horizons                                                                                         dwarf planets

Pluto seen by New Horizons.               Artist’s impression of two other dwarf planets.

Published in: on August 19, 2017 at 11:49  Leave a Comment  

Astronomy for All.

Easter Monday (5th. April 2010) turned out to be a fascinating day – and night! Working during the day I became more and more excited at the prospect of taking part in my very first Messier Marathon. A what you say?

Charles Messier (b. 1730 – d. 1817) began his astronomical life at the age of fourteen when he saw the six tailed comet of 1744 and a few years later when he saw an annular Solar eclipse which was visible from his hometown on July 25, 1748. (An annular eclipse is one in which the moon does not completely cover the sun but leaves a circle of the sun visible it looks like a ring or annulus.)

A NASA image of an Annular Eclipse.
Messier eventually started working at an observatory for the ‘Astronomer of the Navy’ one M. Delisle. In 1757 Messier started looking for the expected return of Halley’s Comet, but as he hunted he came across nebulous objects that might be confused as comets. Objects like the great Spiral in Andromeda and its companion fuzzy object. As he looked for Halley’s comet Messier discovered a comet of his own; as he observed it he came across another comet-like object this time in Taurus (the Crab Nebula) and realised that a catalogue of these comet llike objects was needed.
So began the Messier catalogue with the Crab Nebula being the first entry and so became known as M1 or Messier 1. The great Spiral became known as M31 and its companion M32. As he scanned the skies Messier discovered new objects (M3 and M41) as well as new comets.
What is this Messier marathon? Well around the end of March when the moon is well under way waining or is at new moon phase a happy chance of celestial mechanics allows for observers to try and see all the 110 objects is Messiers’ catalogue in one night. It needs careful planning to see all objects and to ensure that the observer is not looking back and forth across the sky and so wasting time moving the telescope great distances. The first marathons may have begun in the late 1970s so are a recent idea.
Unfortunately for me it was cloudy here in Southport, happily all was not lost. A chap named Gianluca Masi from a town 90 km from Rome decided to use his observatory to do an online marathon. His observatory – the Ballatrix Observatory – can be remotely controlled by users around the world but for Monday night Mr. Masi ran the show.
And what a show! His commentary was fascinating: he talked about how he was taking the images and where we were in the imaging process. Within what seemed like a few seconds an image would appear on the computer screen of one of the Messier objects. Quite amazing.
There were fellow observers from Italy, the USA, Turkey, Argentina and many other countries, all of whom could communicate with Gianluca and each other as the images came in. Not only that but we were treated to the view of the observatory as the marathon was ongoing. Simply fantastic.
Mr. Masi did this under the aupices of Global Astronomy Month a spinoff from the International Year Of Astronomy which occured in 2009. Under the tag-line ‘One World One Sky’ it is an attempt to bring people together through astronomy and to further our understanding of the universe and each other.
Here is the address for the observatory;
http://virtualtelescope.bellatrixobservatory.org/english.html
I couldn’t stay up all night observing even though I was in the comfort of my home and poor Gianluca was outside in a chilly 5C night. What I saw was fantastic, the speed of the camera in taking images was incredible as was the idea that there were hundreds of people all tuned in to gaze at some spectacular sights!

M3, a globular cluster in the constellation of Canes Venatici (the Hunting Dogs.)

Published in: on April 6, 2010 at 19:32  Leave a Comment