The Night Sky May 2017.

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The sky at midnight on the 16th. May 2017. All times GMT.

New moon: 25th Full moon: 10th.

The light evenings of mid-spring present a challenge to Astronomers; fewer dark hours at less convenient times means making the most of the sky when we can.

Look towards the south-west at sunset and you will see the brilliant Jupiter. Over the month it fades slightly from magnitude -2.4 to -2.3 but remains a very noticeable object. It lies in Virgo, Jupiter is above the star Spica which is a first magnitude object, yet compared to Jupiter it does not seem so bright. The moon will pass north of Jupiter on the 8th. and will be a lovely sight. Binoculars or a small telescope will show the four Galilean moons and possibly the cloud belts. Your writer had a look at Jupiter through a three inch telescope a few nights ago and was able to make out the equatorial cloud belts with their distinctive ruddy colour and the moons. SO give it a go!

Rising at 23:30 mid-month and by 22:30 at the end of the month Saturn brightens from magnitude 0.3 to 0.1 over the month. It is to be found in Sagittarius and so will be low in the sky. The moon passes just below Saturn on the 14th. Saturn is a beautiful sight and is always worth a look.

Although there are only two planets (which are fantastic objects to observe) there are other things to look at. If you find Leo, the star to the left is called Denebola, to the left of there lies the Virgo cluster. This is a rich area of galaxies which form part of the ‘Local Cluster’ of galaxies to which our Milky Way belongs. There are over 2000 galaxies in the Virgo cluster, many of which can be seen by amateurs – they will appear as fuzzy blobs, but don’t let hat put you off. The light you see form them has be travelling to your eye for millions of years!

On this Day…

90 Years Ago – May 20th.-21st. 1927: Charles A. Lindbergh made the first solo nonstop flight across the Atlantic Ocean. Lucky Lindy’s single-seat, single engine aeroplane was called the Spirit of St. Louis. It began the flight from Roosevelt Field in New York and landed at Le Bourget Air Field just outside Paris.

45 Years Ago – May 24th. 1972: U.S. President Richard M. Nixon and USSR Premier Aleksey N. Kosygin signed an agreement for cooperation in the exploration of outer space for peaceful purposes which included the docking in space of US/USSR spacecraft in 1975. It was signed in Moscow.

5 Years Ago – May 22nd. 2012: Dragon C2/C3 was launched from Cape Canaveral by a Falcon 9 rocket. The spacecraft was the first fully functional Dragon spacecraft on the Commercial Orbital Transportation Services (COTS) C2+ Demonstration Mission for NASA. It successfully docked with the ISS and was later recovered.

Published in: on May 2, 2017 at 11:32  Leave a Comment  
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March Night Sky.

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Graphic from http://www.heavens-above.com

Night sky at 01h on the 20th. March.

Full Moon; 12th. March. New moon; 28th. March.

The Vernal or Spring equinox occurs on the 20th. March

Clocks go forward one hour on the 26th.March.

Spring is approaching and the sky is beginning to show changes as well. The winter constellations are disappearing in the west and spring constellations of Leo and Virgo are beginning to dominate the sky bringing their own treasures. (All times are in GMT.)

Mercury begins to make an appearance this month but as it is close to the Sun it is difficult to see. It fades from magnitude -1.7 at the start of the month to -0.4 by the end of the month. The end of the month is also the best time to see this elusive world as it sets around 20:30 a good couple of hours after the Sun. Make sure the Sun has set before event trying to find it.

Venus’ domination of the early night sky is coming to an end. It fades from magnitude -4.4 to -4.1 over the month but still remains a stunning sight. Venus sets just after 9pm at the start of the month and around 19:15 towards the end disappearing into the twilight.

Mars dims slightly this month from magnitude 1.4 to 1.6 as it moves from Pisces into Aries. It remains well placed for observation as it sets later as the month progresses around 21:50 at the start of the month to 22 hours by the end. The moon passes by twice this month; on the 1st and the 30th Mars will lie just to the North of the moon making a helpful finder.

Jupiter rises shortly after 8pm and so is visible all night long. It remains in the Virgo above Spica the constellation’s brightest star. The moon lies just to the north of the giant planet on the 14th and will make a lovely sight. Don’t forget to use binoculars to follow the paths of its four biggest moons as they orbit the planet.

Saturn remains an object for night owls this month rising around 03:30 at the start of March and by 02:40 at the end. It is to be found in Sagittarius which itself is a lovely rich constellation full of deep sky jewels. Being in Sagittarius also means that sadly Saturn will not be very high in the sky. The moon passes just to the north of the ringed planet on the 20th.

 

On This Day…

105 Years Ago –March 23rd. 1912: Dr. Wernher von Braun, the father of modern rocketry, was born in Wirsitz, Germany (now Part of Poland).

80 Years Ago — March 6th. 1937: Valentina Nikolayevna Tereshkova was born in Maslennikovo, in the Yaroslavl Region of the USSR. She was the first woman in space when she was launched aboard Vostok 6, on the 16th. June 1963.

70 Years Ago — March 7th. 1947: The first photograph was taken from space by a V2 rocket 100 miles above White Sands, New Mexico.

40 Years Ago – March 10th.1977: The rings of Uranus were discovered using the Kuiper Airborne Observatory. They planet was to be used to observe the occultation of the star SAO 158687 by Uranus to study the planet’s atmosphere, when instead the star seemed to flicker, indicating the rings. An unexpected and lucky discovery!

15 Years Ago – March 25th. 2002: Shenzhou 3 (Divine Vessel 3), a Chinese unmanned spaceship, was launched by a Long-March 2F rocket from the Jiquan Space Launch Centre in the north-western Gobi desert. It consisted of three modules: a propulsion section, a conical re-entry capsule, and an orbiter. The capsule was equipped with all that would be needed for a manned flight.

Published in: on February 28, 2017 at 15:39  Leave a Comment  
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February’s Night Sky.

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Sky at midnight on 22nd. February.

(Sky map generated from Heavens-Above.com)

Full Moon; 11th. February. New Moon; 26th. February.

Venus dominates the early evening sky: it is visible from sunset until around 21:15 shining at a magnificent -4.4. have a look at it with binoculars and see if you can make out its shape; it should look like a half-moon. This shape is known properly as ‘Dichotomy.’

Diagonally up to the left from Venus you will find Mars. It is a lot feinter than Venus shining at magnitude 1.1 it fades slightly over the month to 1.3 by the 28th. it sets at 21h50 by the month’s end. Even through a telescope not much detail will be seen as it is a very small object. It is still worth having a look at all the same. On the 1st Mars lies in-between Venus and the Moon.

Rising at 23:30 at the start of the month and at 21:40 by the end is the mighty planet Jupiter. It shines at a bright magnitude of -2.0 brightening to -2.2 by the 28th. Lying in the constellation Virgo, Jupiter can be found just to the north of the bright star Spica. Jupiter is always worth observing; look out for the four main moons of the planet; they are called the Galilean satellites as they were first observed by Galileo in 1610. Over a few nights you will be able to see them change position as they move around the planet. Through binoculars or a telescope they look like stars but you will know they are moons by the speed they change position. The moon passes just above Jupiter on the 15th and 16th.

If you want to see the ringed planet Saturn you’ll need to get up early. It rises around 5:10 in the morning at the start of February and at 3:30 by the end of the month. Although it is not too bright at magnitude 1.4 it lies in the unremarkable and feint constellation of Ophiuchus, the thirteenth sign of the zodiac. The moon passes by Saturn over the nights of the 20th. and 21st. to help you find it.

On This Day…

111 Years Ago – February 7th. 1906: Birthday of Clyde Tombaugh, discoverer of planet Pluto.

87 Years AgoFebruary 18th. 1930: Pluto was discovered by Clyde W. Tombaugh of the Lowell Observatory, Flagstaff Arizona.

72 Years AgoFebruary 1945: Arthur C. Clarke wrote a letter to the editor of Wireless World describing geostationary communication satellites.

26 Years AgoFebruary 7th. 1991: the Soviet space station Salyut 7 re-entered Earth’s atmosphere at 04:00 UTC.

size-of-space-stations

A comparison of the sizes of space stations and the Shuttle.

From top left; Salyut 1 and Skylab. Below them Mir. On right at top Salyut 7, at bottom the Shuttle and the big structure is the International Space Station.

Published in: on January 24, 2017 at 14:11  Leave a Comment  
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January’s Night Sky.

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The night sky at 01h30 on the 20th.

(Map generated on Heavens-Above.com)

Full Moon 12th. January. New Moon 27th. January.

Only three planets are visible this month; we start off with Venus. As soon as the Sun sets it is an easy to find shining at magnitude -4.4 in the south-west. By mid month it sets just before 9pm. Venus is almost a half crescent at the moment and it is easily noticed through binoculars.

Mars is a lot feinter than Venus at magnitude +0.9 and shines like a red star a little to the left of Venus. Not much detail is visible even through a telescope as it is such a small object.

Jupiter rises before 01:30 and shines at magnitude -1.8, brightening to -2.0 by the end of the month, in the constellation Virgo. It lies just above Spica, the brightest star in the constellation, which is outshone by the brightness of the king of the planets.

This month sees the Quadrantids meteor shower. It peaks on the 3rd but continues on until the 12th. The radiant, the point from which they appear lies close to he constellation Boötes.

Published in: on January 24, 2017 at 14:01  Leave a Comment  
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“The Stars are Painted with Unnumber’d Sparks…”

Little did William Shakespeare know how true were those words he made Caesar utter. Our eyes can see only ‘visible light’ which is a small amount of the electromagnetic spectrum, there is so much more we can’t see without the help of technology.

The Electromagnetic spectrum is a term which scientists use to describe the entire range of light that exists: everything from radio waves to gamma rays, including x-rays and microwaves are all forms of light.

elctromagnetic-spectrum

Electromagnetic spectrum. (NASA)

As can be seen from the chart visible light covers just a fraction of what there is to see. It turns out that different objects in the universe radiate at different wavelengths, some we can see – like light – some we can’t. Some can be observed from Earth – for example radio waves – and some can’t, because the Earth’s atmosphere blocks them, like gamma rays.

For wavelengths absorbed by the atmosphere we have to build satellites and send them into space – often a good distance from Earth to allow them to be cool enough to do their work; the Herschel Space Observatory which observed the infrared orbits 1,500,000 kilometres (930,000 miles) from Earth (by comparison the International Space Station orbits just 400 kilometres from Earth.)

Objects can emit radiation at different wavelengths and that can give us additional insights into their nature. The hotter the object, the shorter the wavelength (the distance between two peaks or crests) and the more energetic it is.

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The shape of an electromagnetic wave (radio, visible etc.)

The following images of the Sun were taken in ultraviolet and visible light on the same day. The difference in what you can see is remarkable;

 

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UV light.

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Visible light.

Astronomers at the Murchison Wide Field Array (MWA) radio telescope in Australia decided to observe the universe at radio wavelengths. The survey known as the GaLactic and Extragalactic All-sky MWA (GLEAM) shows what the Milky Way and 300,000 galaxies look like if we could see radio waves.

The human eye can only see three primary colours (red, blue and green), the Mantis shrimp can see in twelve primary colours, GLEAM ‘saw’ in twenty primary colours, beating every living thing and revealed the remnants of explosions from the most ancient stars in our galaxy, and the first and last gasps of supermassive black holes;

galaxy-visibleIn visible light.

 

galaxy-radioIn radio light.

And if you want to see what it all looks like in a variety of wavelengths try this;

http://gleamoscope.icrar.org/gleamoscope/trunk/src/

The MWA is soon to become part of the Square Kilometre Array (SKA) of radio telescopes working with radio observatories in South Africa and Jodrell Bank. Together they will be able to make even better maps of those unnumber’d sparks.

 

 

“IT’S LIFE JIM…” OR IS IT?

marvin-the-martian1

 

 

 

 

 

Looney Tunes character Marvin

 

We really are obsessed with finding life in space. If it’s not Martian invaders á la Orson Welles it’s Marvin the Martian hunting down poor old Bugs Bunny. Tales of visitations from and abductions by aliens abound on the internet. And we have telescopes dedicated to listening for signals or spotting unusual variations in the light from Sun like stars.

There have been two in particular that have fuelled the imagination, especially of copywriters. The first is KIC 8462852 also known as Tabby’s star after one its discoverer Tabetha Boyajian. This star is 1,480 light-years away in Cygnus and is an f-type star, slightly younger than the Sun but otherwise pretty similar. In October 2015 Astronomers at Yale found it displayed some unusual light variations.

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The position of Tabby’s star.

 

A lot of stars vary in brightness and output (even the Sun albeit very little) and are well understood; they may have companion stars crossing in front of them blocking off some light, think Algol (beta Persei) or there may be a dense cloud that passes by doing the same thing as it orbits a star (as is the case with epsilon Aurigae, which has a noticeable 27 year period.)

 algol-light-curve1

(Notice how much more regular are the dips for Algol in brightness than for Tabby’s star below.)

The way the light changes for these types of objects is pretty straightforward and smooth. Not so for Tabby’s star; astronomers noticed that it faded at first by about 0.34% over a few years but it then in just 200 days it faded by 2.5%. It then carried on fading in its previous way. No star near-by showed similar patterns.

The Kepler space telescope had been monitoring Tabby’s star for a number of years and showed that in 2011 and 2013 the star dimmed a very dramatic way. It had faded by a whopping 22%. This dimming could last between five and eighty days at a time. Something very big had to be passing in front of it. (Flux refers here to the brightness of the object.)

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This led some to suggest a Dyson Sphere. In 1960 theoretical physicist Freeman Dyson suggested that an advanced civilisation might be able to build and sphere or shell to encase a star to harness its power, or that a swarm of satellites or solar panels could surround a star, known as a Dyson swarm, could do the same thing. A Dyson swarm would be easier than an all encompassing sphere to build but still is beyond our ability. Other fanciful suggestions have been gigantic space habitation platforms or even artificially built occulting masks that deliberately dim the star to alert other species that there is life there.

As a result a lot of radio telescopes were turned towards the star to listen for any signal that might suggest life. Sadly nothing has, so far, been heard.

As with the ‘Little Green Men’ signal that ushered in the discovery of the super regular emissions of pulsars people are quick to imagine the fanciful; the reality is likely to be slightly more prosaic but none the less interesting. Current theories suggest the unusual diming may be caused by the break-up of a lot of really large comets orbiting the star (although how this would happen is debatable) or it could even be errors with the data…we still don’t yet know.

But, if you’re hoping for aliens another 234 stars have piqued interest. A paper released on arXiv.org claims that after looking at 2.5 million stars surveyed by the Sloan Digital Sky Survey 234 have a very unusual and puzzling light signature. One of the lead astronomers for this paper EF Borra (who works in Canada) claims these light patterns are similar to those he proposed in an earlier paper that might come from an alien civilisation signalling their existence to others. (Here is the link to the paper; https://arxiv.org/abs/1610.03031 )

Could they be from aliens? This is what the scientists themselves say in their pre-amble to the article; “We find that the detected signals have exactly the shape of an ETI signal predicted in the previous publication and are therefore in agreement with this hypothesis. The fact that they are only found in a very small fraction of stars within a narrow spectral range centred near the spectral type of the sun is also in agreement with the ETI hypothesis. However, at this stage, this hypothesis needs to be confirmed with further work.” They do go on to add a note of caution; “Although unlikely, there is also a possibility that the signals are due to highly peculiar chemical compositions in a small fraction of galactic halo stars.”

(ETI stands for Extra-Terrestrial Intelligence.)

Well a lot more studying of these signals from a lot more institutes with a lot more equipment will be needed before any definite answer can be given. Perhaps the brand new Chinese radio telescope FAST may look at these signals…

478138-five-hundred-meter-aperture-spherical-telescope-fast-world-s-largest-radio-telescope-tianyan-telescope-guizhou-province-science-technology-space-mission-telescopic-equi1

FAST stands for Five hundred metre Aperture Spherical Telescope and is one of the largest radio telescopes in the world. In area it is roughly the equivalent to thirty football pitches or 200,000 square meters. Work began on building it in 2011 and it is already built and after undergoing tests before beginning its working life on the 25th September 2016. The web page for FAST is; http://fast.bao.ac.cn/en/

There is a larger radio telescope in Russia called RATAN 600 which is 576m in diameter, but, unlike FAST, is composed of segments that make up the whole dish (895 of them of size 2×7.4 m.) It was involved in the detection of an unusual and regular signal which could have been alien in origin, however after other observatories failed to repeat the observation, and because of the frequency it was observed it was decided that RATAN had picked up signals from a secret military reconnaissance satellite.

                                   1987_cpa_58931RATAN commemorated in a 1987 stamp.

So, you do need to be careful when making assumptions about unusual observations, as it could be alien in origin or more likely something else all together!

 

 

A Living Fossil.

It seems the more we know the more we find out. In the natural world there are creatures nick-named ‘living fossils.’ The phrase was first used by Charles Darwin and relates to living things that have remained largely unchanged for millions of years. Two very different examples are Ctenophores and Gingko Biloba.

Ctenophores are also known as comb jellyfish. They propel themselves through the sea using lots of tiny hairs known as cilia. They are believed to have first appeared on Earth 700 million years ago which could mean that humans descended from them!

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A Ctenophore.

Gingko Biloba, or the maidenhair Tree, is the only one of its kind. It has neither ancestors nor evolved descendants. It is a truly ancient plant with fossil records of it dating back to the Permian era some 270 million years ago. It is much used today for its healing and soothing properties.

ginkgofossilthumb

A fossilised Gingko leaf.

So what has this to do with Astronomy? Well Astronomers have been looking at one of the globular clusters that are attached to the Milky Way, and have concluded that it is a living fossil from the earliest times of the galaxy: Terzan 5 is 19 000 light-years away and orbits the central bulge of the galaxy. It appears at the moment to be coming towards us at about 90Km/s.

The Milky Way is a spiral galaxy, with most of its stars to be found at the centre where they form a bulge. If you imagine our galaxy as two fried eggs put back to back the yolks represent the bulge.milky-wayHow our galaxy might look from afar.

It was only discovered in 1968 by French astronomer Agop Terzan. It lies in the constellation Sagittarius and is obscured by the number of stars in the area making it hard to find. Astronomers noticed in 2005 to have two distinct populations of stars with an age gap of 7 billion years. It was thought that Terzan 5 might have been the remnant of a dwarf galaxy that got too close to ours and was disrupted (broken up) by the gravity of the Milky Way.

Peering through the thick dust clouds of the galactic bulge an international team of astronomers has revealed the unusual mix of stars in the stellar cluster known as Terzan 5. The new results indicate that Terzan 5 is in fact one of the bulge's primordial building blocks, most likely the relic of the very early days of the Milky Way. This picture is from the Multi-Conjugate Adaptive Optics Demonstrator (MAD), a prototype adaptive optics system used to demonstrate the feasibility of different techniques in the framework of the E-ELT and the second generation VLT Instruments. The star colours are from the Hubble image of the same star field.

This picture is from the Multi-Conjugate Adaptive Optics Demonstrator (MAD), a prototype adaptive optics system used to demonstrate the feasibility of different techniques in the framework of the E-ELT and the second generation VLT Instruments. The star colours are from the Hubble image of the same star field.

It has now been discovered that this is not the case. Using instruments on the Hubble Space telescope, the WM Keck telescope and the ESO’s Very Large Telescope (VLT) in Chile Astronomers have been taking another look at these two lots of stars. They found that as well as the age gap they are made up of very different elements. This age gap indicates that the star formation process in Terzan 5 was not continuous, but was dominated by two distinct bursts of star formation.

This means its ancestor must have had large amounts of gas for a second generation of stars, something along the size of at least 100 million times the mass of the Sun! It had to be massive for it to have survived the 12 billion years since the galaxy formed without being disrupted They have also found that he stars in Terzan 5 have very similar properties to those found in the galactic bulge.

These unusual properties, which are uncommon amongst globular clusters, are why Astronomers are calling it a living fossil. The current theory of how galaxies form requires vast clumps of gas and stars to interact and then merge and dissolve to form the primordial bulge of the Milky Way in the process. Some of Terzan 5s characteristics “…resemble those detected in the giant clumps we see in star-forming galaxies at high-redshift, [that is galaxies far away from us] suggesting that similar assembling processes occurred in the local and in the distant Universe at the epoch of galaxy formation.” according to lead Astronomer Francesco Ferrari.

The research presents a possible route for astronomers to unravel the mysteries of galaxy formation, and offers an unrivalled view into the complicated history of the Milky Way.

If you want to know where Terzan 5 is, here is a map; the region (Sagittarius) is visible form the UK but the cluster itself, well that is a different matter!

This chart shows the rich constellation of Sagittarius. Among the many star clusters in this part of the Milky Way lies Terzan 5, a stellar cluster which resembles a globular cluster. This picture plots most of the the stars visible on a dark clear night with the naked eye.

This chart shows the rich constellation of Sagittarius. Among the many star clusters in this part of the Milky Way lies Terzan 5, a stellar cluster which resembles a globular cluster. This picture plots most of the the stars visible on a dark clear night with the naked eye.

 

Published in: on September 8, 2016 at 16:17  Leave a Comment  
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PLANETS, PLANETS EVERYWHERE…

It is a remarkable thing to think about. Just twenty four years ago we knew of only nine planets (Pluto had yet to be demoted) and they were all in our solar system. The first planets to be detected were found in 1992 orbiting a very unusual object, a pulsar called PSR1257+12. Three planets were discovered orbiting this rapidly rotating neutron star. (The name references its position in the sky.)

A neutron star is the remains of a large star that has become a supernova, but was too small to form a black hole. Instead it leaves behind a dense core. Pulsars are a form of neutron star which has a very powerful magnetic field which can be detected from earth if the beam of radiation passes in our line of sight. They are nick-named ‘cosmic lighthouses’ as the beam of radiation spins past very regularly, as does the light from a lighthouse. When they were first discovered in 1967 by British astronomer Jocelyn Bell the regularity lead to them being thought of as artificial as it was too regular for a natural event.

PSRs_discovery

The paper trace of the discovery of the first pulsar, spinning at a rate of once every 1 1/3 seconds. (www.jb.man.ac.uk)

Then, on the 6th. October 1995 two Astronomers in Geneva announced the discovery of a planet orbiting 51 Pegasi, a main sequence star similar to our own.

From then on the discoveries of new worlds gathered pace, initially large planets, some bigger than Jupiter were the ones being found. The techniques in the ‘early days’ of discovery meant that they were found only because of their size and proximity to their host stars. This led to their being called ‘Hot Jupiters.’

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If you want to find the star 51 Peg it lies very close to the Square of Pegasus and is visible easily in the northern hemisphere.

Very quickly, though, smaller and smaller planets were discovered. Today (28th. August 2016) 3,518 exoplanets are known (for details visit exoplanet catalogue at www.exoplanet.eu ). Sizes vary for these planets as can be seen by this NASA graphic:

717582main_NewCandidatesbySize-07Jan13_full

Of course as soon as planets were found the hunt then began for planets that might support life. As far as we understand, life needs amongst other things a planet between one and 10 times the mass of the Earth. It needs to be big enough to hold onto an atmosphere but not so big that here is too much hydrogen and there needs to be water. So we need to find planets where water was likely; that means they would have to lie in a region which was not too close to its star (where it would be too hot for water and possibly life) and not too far (where it would be too cold for liquid water) but in a region that was just right. This region is the Habitable or Goldilocks zone.

Now, depending on the size and age of a star the Goldilocks zone will vary; around a cool, red dwarf a planet would need to be much closer than around a star like the Sun. A number of good candidates have been found; (although there is some doubt about Gliese 581g as there have been no successful follow-up observations of planets. This is a criterion that needs t be met to ensure that the discovery is not a ‘false positive.’)

How do Astronomers look for an exoplanet? Well there are a number of techniques; they can be detected directly and be imaged (this is the most difficult method) or they can be detected indirectly, discovering the existence by the effect on the host star.

Exoplanets-potentially-habit_-credit_PHL-Arecibo1-1024x512

The direct detection method of imaging an exoplanet is difficult because a planet (even a super sized ‘Jupiter’) is very dim when compared to a star. The star literally outshines its planets. To try and see planets this way it is necessary to block out the star’s light. To do this an instrument called a Chronograph is used. It covers the disk of the star but leaves the outer regions of its atmosphere visible allowing any planets to shine through. Think of a total solar eclipse and how, when the Moon covers the Sun completely we can see the outer layers of our star’s atmosphere, this is a natural chronograph.

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Total Solar eclipse showing the Corona, the Sun’s outermost layer.

Observing a planet this way is vital though if we are to try and examine its atmosphere to determine how much water it has and if there are any chemical signs of life. (In 2010 the European Southern Observatory’s (ESO) Very Large Telescope (VLT) captured the first direct spectrum of an exoplanet!)

There are a number of indirect ways of detecting exo-planets including watching for planets transiting the host star. A transit occurs when an object passes in front of another object; from Earth we see this when Venus or Mercury pass in front of the Sun. When an exo-planet transits its host it dims the star ever so slightly. By measuring how much the star is dimmed (using an instrument known as a photometer) and how long the transit lasts Astronomers can work out the size of the planet, its orbit and the composition of the planet’s atmosphere.

Spacecraft like the Kepler telescope and COROT use this method and have had much success in finding new bodies. Future missions like ESA’s Darwin and NASA’s Terrestrial Planet Finder will search for oxygen, carbon dioxide and chlorophyll. These missions are planned for launch in the next decade.

The big news though is that an Earth like planet has been found very close our Solar system; on the 24th. August 2016 ESO announced the discovery around the star Proxima Centauri.

The location of Proxima Centauri in the southern skies

This picture combines a view of the southern skies over the ESO 3.6-metre telescope at the La Silla Observatory in Chile with images of the stars Proxima Centauri (lower-right) and the double star Alpha Centauri AB (lower-left) from the NASA/ESA Hubble Space Telescope. Proxima Centauri is the closest star to the Solar System and is orbited by the planet Proxima b, which was discovered using the HARPS instrument on the ESO 3.6-metre telescope.

Credit: Y. Beletsky (LCO)/ESO/ESA/NASA/M. Zamani.

This discovery is special because the planet has been found around the closest star to us. Proxima Centauri lies 4.35 light-years away. It is to be found in the constellation Centaurus, but is sadly too far south for us in Britain to see. It is very faint as it is cool red star, it lies close to the brighter pair of stars known as Alpha Centauri AB. The planet has been designated Proxima b, and orbits its parent star every 11 days. It has a temperature suitable for liquid water to exist on its surface. This rocky world is a little more massive than the Earth and is the closest exoplanet to us — and it may also be the closest possible abode for life outside the Solar System.

Proxima was monitored as part of the Pale Red Dot campaign (https://palereddot.org/) during the first half of 2016. Proxima Centauri was regularly observed with the HARPS spectrograph on the ESO 3.6-metre telescope at La Silla in Chile and simultaneously monitored by other telescopes around the world.

The Pale Red Dot Campaign

Pale Red Dot was an international search for an Earth-like exoplanet around the closest star to us, Proxima Centauri. It used HARPS, attached to ESO’s 3.6-metre telescope at La Silla Observatory, as well as other telescopes around the world. It was one of the few outreach campaigns allowing the general public to witness the scientific process of data acquisition in modern observatories. The public could see how teams of astronomers with different specialities work together to collect, analyse and interpret data, which ultimately confirmed the presence of an Earth-like planet orbiting our nearest neighbour. The outreach campaign consisted of blog posts and social media updates on the Pale Red Dot Twitter account and using the hashtag #PaleRedDot. For more information visit the Pale Red Dot website: http://www.palereddot.org

Observations have revealed that Proxima Centauri is approaching Earth at about 5 kilometres per hour — normal human walking pace — and at times receding at the same speed. This regular pattern of changing radial velocities repeats with a period of 11.2 days. Careful analysis of the resulting tiny Doppler shifts showed that they indicated the presence of a planet with a mass at least 1.3 times that of the Earth, orbiting about 7 million kilometres from Proxima Centauri — only 5% of the Earth-Sun distance.

Proxima is a very different star to the Sun, not just in size and colour but also in activity; the conditions on the surface may be strongly affected by the ultraviolet and X-ray flares from the star — Proxima b receives 60 times more high-energy radiation than the Earth far more intense than the Earth experiences from the Sun. This made detecting a planet around it even harder! So far the rotation of the planet is unknown; it may be that one side always faces the star, whilst the other is in perpetual night. The border between these areas might be subject to intense winds – winds which may howl across the planet. This tidal locking of a body so that it faces the same direction is called synchronous rotation – the same reason we only see one side of the moon.

 

Artist's impression of the planet orbiting Proxima Centauri

This artist’s impression shows the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The double star Alpha Centauri AB also appears in the image between the planet and Proxima itself. Proxima b is a little more massive than the Earth and orbits in the habitable zone around Proxima Centauri, where the temperature is suitable for liquid water to exist on its surface.

Credit:ESO/M. Kornmesser

Conditions on Proxima b may be very different to Earth and any life there will have had to adapt to its unique conditions, also the suitability of this kind of planet to support water and Earth-like life is a matter of intense debate. Major concerns that count against the presence of life are related to the closeness of the star. For example gravitational forces probably lock the same side of the planet in perpetual daylight, while the other side is in perpetual night. The planet’s atmosphere might also slowly be evaporating or have more complex chemistry than Earth’s due to stronger ultraviolet and X-ray radiation, especially during the first billion years of the star’s life. However, none of the arguments has been proven conclusively and they are unlikely to be settled without direct observational evidence and characterisation of the planet’s atmosphere.

Of course in the far distant future perhaps they will even become holiday destinations…!

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There is much to learn and discover, exciting times lie ahead!

 

 

Don’t be so Sure.

 

There is a meme wandering the internet which says;

“Born too late to explore the World,

Born too early to explore the Universe.”

At first glance it is depressingly true. After the initial despair the truth of it becomes more questionable.

It is true there will not be another Magellan or Cooke – discovering new lands and new peoples. That may not be a bad thing in some ways; think of how badly indigenous peoples were treated as a result of their voyages. It is also true that we are unlikely to have a region or feature named after us; no more Van Diemen’s Land. (Curiously it was discovered by an explorer named Abel Tasman who named it after his sponsor Anthony Van Diemen. Later it was renamed after Tasman and is now Tasmania!)

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Abel Tasman commemorated on a 1963 Australian stamp.

It is true also that we are unlikely to tread on untrodden land again but at the same time it means we are unlikely to suffer from unknown illnesses, be attacked by wild locals or bites from venomous beasts with no cure as happened to those early explorers.

On the other side, we can travel to Australia in twenty-four hours as opposed to the months by sea in wooden death traps. We can pop over to Rome or Paris in a matter of hours instead of days. Then we have the benefit of technology to get the most out of our visits: on-line maps, guides and local web-sites. Or instead of using tech we can wander around towns and cities safely discovering sights for ourselves.

Isn’t that the key too? We can go to those places and discover for ourselves new things. Okay, we may be the ten millionth to see the Coliseum but that first view with our own eyes is our own discovery. It will be something we can then talk about and probably bore our friends over too.

Of course you may be lucky enough to be a marine biologist who gets to travel deep under oceans finding new life, or an entomologist thrashing through the Rainforest looking for a new butterfly. However as with the explorers of old not everyone can do that but often we can follow them on-line, on screen or in print from the comfort of a mosquito and scurvy free home. (Hopefully!)

So I would suggest that the first part of the phrase is very wrong. We are alive at a time when exploring has never been easier, safer and more affordable.

What about ‘…Born too early to explore the universe’? This is harder to discount. So far about 600 people have flown into space. (The Fédération Aéronautique Internationale (FAI) defines spaceflight as any flight over 100 kilometres in altitude.) Which in the fifty-six years of manned spaceflight (2016) is a pretty poor show.

faiFAI logo.

The pangs of envy and despair at not being able to get to space to experience the things astronauts can is so very real. The recent Principia mission of British astronaut Tim Peake is a case in point; he seemed to have so much fun and get so much out of his trip that you can’t help but be jealous.

Many was the time during the 80s when the only way I could find out about an on-going Shuttle mission was by tuning in to the Voice of America (VOA) on shortwave and hoping for a snippet of information in the news programme. Of course the fun part also involved tuning into VOA and through the crackles and fading signal listening to a live broadcast of a launch. Many a cassette was filled with recordings of just that.

We then had to rely on the BBC or ITV to give an update which all too often did not happen.

With the advent of the internet, superfast broadband, high definition cameras and live streaming we do get to see and hear a lot more of the astronauts time in space than we ever did. Today we can watch in real time, even streaming the mission through our TVs to watch in glorious big screen.

So, to that extent things are better than ever. It’s not as good as being here but…and with the advent of VR devices it could become a lot more immersive an experience.

Okay it’s not the same as flying through the fountains of Enceladus or drinking Saurian brandy on Risa. Yet we are still able to see some amazing sights:

enc1The fountains of Enceladus.

Just look at these images of Saturn’s moon Enceladus. Images that we wouldn’t have even dreamed of twenty years ago can be viewed by anyone at any time. Space probes are travelling all around the solar system and out of it. The pictures from Pluto sent by a speeding New Horizons probe are breath taking, Juno promises even more at Jupiter. Cassini continues its mission around Saturn, the astronauts aboard the International Space Station continue to take amazing photos of Earth, all of which we can enjoy.

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Enceladus and Saturn’s rings.

Even for the crew of the Starship Enterprise it took a while to get anywhere from hours to weeks depending on where they were and their destination. Think of all that time away from home, in the humdrum daily job of warp coil engineer or security officer. The glamour and new views were far and few between.

But not for us! Take a telescope outside and point it. Within minutes you could have travelled 2.2 million light years to the Andromeda galaxy, something even Star Trek was unable to do! At our eyepiece is an entire universe. It is possible to see quasars billions of light-years away; true they only look like a star in the eye-piece but you wouldn’t want to get too close anyway. Or if that’s too mind numbingly distant you can always view the moon a mere 3 days or quarter of a million miles away.

If they intrigue you then you can find out all we know about them from on-line resources, observatories and space agencies. All from the comfort of you’re home.

Yes, it’s not the same, but not all is lost.

Published in: on July 9, 2016 at 13:21  Leave a Comment  
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