In the search for E.T should we be looking for artifical intelligence instead?
SETI, the search for extraterrestrial intelligence has so far been searching for radio signals coming from worlds like earth, but recently some astronomers at SETI one of which who is called Dr Seth Shostak has said that the time for aliens to develop radio technology and AI (artificial intelligence) would be short and that the odds on SETI finding alien life are in favour of finding AI rather than biological life.
Many scientists involved in SETI have been saying for a long time that nature will have most probably solved the problem of life using different chemicals or designs and that not only would alien life not look like us but also that it might not at a biological level even work like us. However most of the SETI scientists agree that alien life would be ‘alive’ in sense that we know it, e.g they would be sentient, be able to reproduce and also have to consume solids and liquids to survive.
But other scientists believe that if our civilisation and the way in which we are advancing technologically is anything to go by then it is highly likely that any alien civilization that have been able to broadcast radio messages into space would very soon after be able of creating thinking machines or AI. Although Dr Shostak does admit that decoding any messages we may receive from alien AI would most likely be more difficult than decoding messages from biological aliens.
This idea of alien AI does provide scientists with new places to look in the search for alien life as Dr Shostak says that AI would mostly want to live in places where both energy and matter are in abundant supply as he believes that these two things would be the only things of interest to machines. this means that SETI may need to focus some of its attention near hot young stars or towards the centre of the galaxy and in globular clusters where the conditions for bilogical life are very hostile but where artificially intelligent aliens may be hanging out.
The large Allen Telescope Array is one of the many radio telescope Arrays scanning the heavens for alien signals Credit: SETI
Joshua Tree Under the Milky Way (Perseids 2010)
This was just one of those videos we had to share!
Recorded by Henry Jun Wah Lee (http://photography.evosia.com/) at the Joshua Tree National Park in California with a Canon 5D Mark II, EF 16-35mm L at f/2.8, 6400ISO and 20s exposures. For still images, and details on this video click here.
Credit: Henry Jun Wah Lee
We know how black holes form. Don’t we …?
Recently it seems the more we look into the stars and galaxies that populate this universe, objects we used to thing we had figured out quite well, it has become clear that we are not as educated in the workings of the cosmos as we once thought.
The Mystery Magnetar Credit: ESO
The basic results of star death have been thought to be rather simple. A low mass star, that is one with less than about 10 solar masses forms a white dwarf a medium mass star between 10 and 25 solar masses go supernova and leave behind a neutron star\pulsar. The high mass stars (those above 25 solar masses) also go supernova and create a black hole from their cores’. (The most massive stars are actually theorised to explode and leave nothing – the explosion is so forceful it vaporises the entire star – such an explosion is known as a pair instability supernova but that is for another day).
Astronomers using the ESO’s Very Large Telescope (VLT) have made a very interesting discovery while surveying the super star cluster Westerlund 1, that once again shows that perhaps we don’t know as much as we thought we did. Westerlund 1 is the closest super star cluster to Earth yet discovered, it lies between 3.5 and 5 kiloparsecs (or somewhere between around 11,500 and 16,500 light years if you prefer) away in the southern hemisphere constellation Ara – The Altar.
You may be wondering while the distance figure is less than accurate, unfortunately it is down to the distance being measure itself. It is so far for the more accurate parallax measuring system to be used and so other methods must be employed. These methods can give different results based on different conditions hence the rather large estimate range. Despite this the rough estimate puts the cluster at the outer edge of the Milky Way’s galactic Bar which may go someway in explaining how the cluster grew to such proportions – it contains many high mass stars including a large number of highly evolved supergiants.
The cluster can be seen in its full glory in this annotated image from the ESO’s VLT.
Westerlund 1 Credit: ESO
A larger version can be viewed here.
The labelled magnetar is the star of particular interest in this marvellous cluster. A magnetar is a type of supernova remnant; specifically a neutron star with an incredibly strong magnetic field many thousands of times more powerful than the Earth’s own magnetic field, they are very rare as only a handful have been identified in the Milky Way.
The cluster contains stars that formed in a single formation event over a short period of cosmological time between 3.5-5 million years ago. Using this age figure calculated from the rate of stellar evolution in stars of different masses – the more massive a star is the faster it dies, thus the age of the cluster can be determined by measuring the highest mass star in the cluster (this has been achieved by carefully studying binary systems which allows for the mass of the stars to be accurately measured by detecting stight changes in their orbits). This puts an upper limit on the age of the cluster because had it been any older this star to would have gone supernova.
Neutron stars as I stated above are thought to form from ‘progenitor’ stars of between around 10-25 solar masses. Based on age estimates on the cluster (as detailed above) the magnetar’s parent star weighed in at least 40 solar masses! This means it was well above the mass of a star that was thought to collapse into a stellar mass black hole. Whilst the limit is be no means exact, a star that is almost double the rough limit is very unusual and very interesting.
Whilst no one is quite sure how a magnetar forms as apposed to a ‘normal’ neutron star, it does still have the same basic structure and they are still subject to the gravitational forces that formed them and are constantly trying to crush them further into a black hole. As this has clearly not happened in this case, this single star presents a rather large problem. Some may be quick to say that the accepted mass limit for neutron stars in obviously wrong.
However, as this star seems to be the exception to the rule rather than a common occurrence, perhaps it is circumstances that are to blame, rather than a flaw in our understanding. If the parent star had been contained in a binary system its partner may have removed sufficient mass via mass transfer and accretion and in doing so lowered the mass sufficiently to avoid the total gravitational collapse of the star into a black hole.
Though this idea creates a number of questions too, where is the companion star? As far as we can currently tell the magnetar is alone with out a binary partner though it is quite possible that the force of the supernova detonation blew the pair apart, this helps to explain why the magnetar is on the outer edge of the cluster. Though a massive amount of material would have had to be removed, which makes it a difficult idea for some to accept. Perhaps one day we will know for certain, finding the star’s partner would certainly help.
Who knows the next big discovery could be just around the corner.
I leave you with this artist’s impression video of travelling through the cluster to the magnetar.
Video credit to ESO
Read more about the discovery here and more about black holes here
Image of the Week – 20/08/10 – The Galactic Volcano
Due to the website maintenance this post is a day late. I apologise for the delay.
This image is a combination of data from the Chandra X-ray ( shown in blue) observatory image and one captured in the radio section of the electromagnetic spectrum by NSF’s Very Large Array (VLA) (Shown in red and orange).
The Galactic Volcano Credit X-ray (NASA/CXC/KIPAC/N. Werner, E. Million et al); Radio (NRAO/AUI/NSF/F. Owen)
They show the galaxy M87 an Elliptical galaxy located 55 million light years away in the Northern Virgo Cluster. It contains a well studied AGN (Active Galactic Nucleus) and is one of the most ‘radio loud’ objects visible from Earth.
The below image shows only the Chandra data
Chandra Image of the Galactic Volcano Credit: X-ray (NASA/CXC/KIPAC/N. Werner, E. Million et al)
The cluster containing M37 contains lots of hot gas and dust (this can be seen in the outskirts of the Chandra only image.) Under normal circumstances this material would ‘fall’ under the influence of gravity into the galaxy, cool and form new stars.
The combined data shows that this is not the case with M37 however; its central supermassive black hole has other ideas for the in-falling matter. The black hole has powerful jets blasting into space these pass on some kinetic energy to the cooling gas and dust near the centre of the galaxy and through it into space at supersonic speeds as the plumes of gas visible in the combined image.
This has been compared to the recent eruption of the Icelandic volcano Eyjafjallajokull, which caused significant air travel disruption across Europe. The similarities are not the two effect on humans as M37 is far to distant to have any tangible effect on the Earth or any part of the Milky Way for that matter. In the eruption hot volcanic gasses created at the local site of the eruption threw ash particles high into the atmosphere and allowed them to travel for several thousand miles. This is not unlike the hot x-rays produced by the central black hole ‘uplifting’ the cooler material and carrying it far into space.
To conclude here is an annotated version of the image showing the location of the plumes and black hole in relation to the rest of the image.
Labelled Image of the Galactic Volcano Credit: X-ray (NASA/CXC/KIPAC/N. Werner, E. Million et al); Radio (NRAO/AUI/NSF/F. Owen)
To read more about black holes click here
To read more about this particular galaxy and black hole click here
Scheduled Website Matinence
On August 19th the Young Astronomers website will be undergoing seasonal matinence and organization. The website may be unavailable throughout the day, and some glitches may been seen, please just bear with us. Thank you for your continued reading and support!
-The Young Astronomers Administrators
Young Astronomers’ Quiz No. 1: Asteroids
Answers now available – scroll down!
We thought you might enjoy doing a space quiz every so often! They might be on a particular subject, or they might be general. This one will be on asteroids.
Thank you Astro.Washington for this artist’s impression of two asteroids in space!
How many of these can you answer?
1. Where are most asteroids found in the Solar System?
2. Is an asteroid bigger or smaller than the Moon?
3. What is the name of the biggest asteroid?
4. What are asteroids called when they get dangerous to people?
5. And what ways can we avoid hitting them?
6. There’s been a big news story lately about an asteroid that might collide with the Earth! Do you know when this is supposed to happen?
7. Could we live on an asteroid?
8. What’s the name of the asteroid the Rosetta spacecraft went to see?
9. Why aren’t asteroids round like the planets?
10. Can you name any asteroids, other than the one in question 8?
Answers will be posted in this thread a week from now. If you’d like to, leave your answers – or questions or suggestions – in the comments. Don’t worry, we don’t grade people or offer prizes, so cheating would be pointless – but leaving your answers might prompt a lot of lively discussion and we might all learn new things!
Answers:
1) The Asteroid Belt, i.e. between Mars and Jupiter. (Though Peter tells me it’s a bit more complicated than that.)
2) Smaller.
3) I was going to say Ceres – but I can get things wrong too, to judge by Scibuff’s comment! Mind you, Ceres is still the largest asteroid in the main belt . . .
4) Near Earth Objects.
5) There are various theoretical ways. The current one in favour is attempting to blow it up, but that would probably solve things the least, since that would not alter its course – the (probably now very radioactive!) debris would still be on course to the Earth. An explosion near it might alter its course, though that is also risky. We could also attempt to move it off course. Another solution sounds ridiculous but may be the most effective: paint it black or white to absorb or reflect more of the Sun’s rays. Yes, seriously. Look up radiation pressure. Over millenia, this would actually cause it to move further away from, or nearer to, the Sun.
6) 2182, so there’s really not much to worry about yet.
7) No. Their gravity isn’t strong enough to hold onto air or water.
Lutetia.
9) Their gravity isn’t strong enough to collapse them into a round shape. Gravity constantly tries to pull things to the centre of itself, and a round shape does this the best. That’s why Mount Everest is probably about as high as a mountain will get on Earth. Mountains can be bigger on Mars, and on a neutron star a mountain would be barely detectable! It is thought that the moon Mimas is about the smallest object in the Solar System to have fallen into that round limit.
10) There are lots and lots and lots – too many to name!
Well done Scibuff and Anna Hedge – who’s going to have a go next time?
Image of the Week – The Undead Galaxies – 13/08/10
Astronomers using NASA’s Galaxy Evolution Explorer and the Hubble Space Telescope have made a remarkable discovery, galaxies that have returned from the star formation grave.
Ultraviolet rings surrounding aged galaxies. Image credit: NASA/ESA /JPL-Caltech/STScI/UCLA
The story began with the Galaxy Evolution Explorer’s ultraviolet scan of the night sky, in which it discovered 30 elliptical and lenticular galaxies – generally devoid of hot young stars that produce large amounts of ultra violet light and are also known as early- type galaxies - that were particularly luminous in UV. The Galaxy Evolution Explorer lacked the resolution to identify any detail on the identified galaxies, in essence it could tell that the galaxies where ultraviolet luminous but not why or if there was any features within the galaxies themselves. To pick out the finer details astronomers turned to the Galaxy Evolution Explorer big brother Hubble.
Hubble produced images (a few of which are shown above) of the galaxies and revealed huge ring like structures within around 75% of the galaxies in question, whilst showing that the galaxies themselves contained mostly old ageing stars as you could expect from a more standard early- type galaxy.
This means that the galaxy had aged as usual ending their star formation and becoming ‘red and dead’. Later they must have received a new supply of gas and dust that allowed star formation to begin a new. This second ‘starburst’ is what created the ring as new high mass ultraviolet producing stars were born.
In a few of these galaxies’ it is likely that an ultraviolet echo is visible left over from the galaxies first star producing phase but this cannot explain the bulk of the phenomena. Some of the rings are large enough to encircle a galaxy several times larger that the Milky Way, others even show hints of other structures.
The question now facing astronomers is how this material was delivered into the ageing galaxies; currently there are two main ideas – either a galactic merger or the galaxy simply sucks up enough gas from the interstellar medium to ignite a new burst of star formation.
Proponents of the merger scenario point out that a merger could produce the ring structures observed. Others are just as quick to point out that such a merger needs a precise alignment and so would be exceedingly rare.
All astronomers agree that more detailed observations are required to end the debate. These new observations will look for finer structures within the rings and attempt to detect clouds of hydrogen alpha (a particular type of ionised hydrogen) than marks star formation.
Read more here
Time running for WISE
Animation of WISE in orbit. Credit; NASA
NASA’s WISE (Wide-field Infrared Survey Explorer) is beginning to heat up. The spacecraft needs to be kept at 12 Kelvin (minus 438 degrees Fahrenheit) to function normally. The spacecraft carries two coolant tanks the secondary outer tank is now empty and the craft is beginning to heat up. One infrared detector, the longest-wavelength band which is the most sensitive to head stopped producing any useful data when the craft warmed to 31 Kelvin (minus 404 degrees Fahrenheit). The primary tank which cools the other infrared detectors has a good supply of coolant left and the data quality is still high.
WISE completed its primary mission July 17, 2010. A complete scan of the entire sky in infrared light. The mission so far has taken more than 1.5 million pictures. So far WISE has uncovered 29,000 new asteroids, more than 100 near-Earth objects and 15 comets.
WISE is continuing in a second survey of one-half of the sky as planned but it is feared that the coolant will run out before that scan is finished. NASA scientists say that the scan will identify new and nearby objects, as well as show if any have changed in brightness. It may also help to confirm oddball objects picked up in the first scan.
The Tarantula Nebula – like you have never seen it before
Astronomers working with the ESO’s VISTA (Visible and Infrared Survey Telescope for Astronomy) telescope have produced this stunning image of the Tarantula Nebula in the Large Magellanic Cloud.
Tarantula Nebula as seen by VISTA Credit: ESO
For a larger image click here
The Large Magellanic Cloud is one of the Milky Way’s satellite galaxies. It orbits the Milky Way and is very close to Earth, in universal terms at only 160,000 light years away. It like its cousin the Small Magellanic Cloud, is an irregular dwarf galaxy that has been caught in the gravitational influence of the Milky Way in the same way a moon orbits a planet only on a much larger scale.
The LMC is host to the most active region of star formation in the Local group – Doradus 30 or the Tarantula Nebula.
The nebula itself is around 650 light years across and contains a dense star cluster at its centre R136. This cluster is only around 35 light years in diameter but contains 450 000 times the mass of the sun! At its core there are a tight group of 13 gigantic stars including R136a1 – the largest and most luminous star yet discovered by astronomers at around 265 solar masses and at 10,000,000 times more luminous than Sol (look out for another post on this monster that will be coming out soon 
). This star cluster is the bright area near the centre of the main nebula in the above the image.
It is this cluster that provides most of the energy to make the nebula visible. In fact the nebula is so luminous that if it was placed at the same distance from Earth as the Orion Nebula (the closest star forming region to us) it would cast shadows!
The Tarantula nebula is not the only interesting feature captured in this VISTA image. Some of these features are captured in this composite image of the most interesting areas of the main image.
Extracts from the VISTA Magellanic Cloud Survey view of the Tarantula Nebula Credit ESO
Top right is the amazing supernova remnant SN 1987A which looks rather insignificant in this wide field shot however I assure you it is not. If you would like to read more about SN 1987A try reading this post.
Bottom left is the globular cluster NGC 2100 which is still young for a globular cluster. It lies east of the Tarantula nebula, and may soon have a new neighbour globular cluster in R136 which given its high density and mass is expected to from into a globular cluster as it develops.
Finally in the bottom right are NGC 2080 or The Ghost Head Nebula and NGC 2083. The Ghost Head Nebula is a star forming region and has been captured close up in this Hubble Space Telescope image.
NGC 2080 Credit: NASA; ESA; HST
NGC 2083 is an emission nebula\star cluster and thus is emitting its own light making it visible to the survey.
These features can be seen in relation to the main image here on the annotated version.
The image have been collected as part of the VISTA Magellanic Cloud Survey (VMC), which intends to cover an area of the sky roughly the area of 1000 full moons in an effort to fully map the complete Magellanic system (both the LMC and SMC). With the hopes of obtaining a complete knowledge of the structure of the system and the areas star formation history. The survey is expected to take the first five years of VISTA’s observational life.
The survey captures images in the near-infra red bad of the electromagnetic spectrum which allows it to cut through the majority of the dust that normally obscures young stars and other interesting objects from view in the visible spectrum.
VISTA is an ESO telescope housed at the Paranal Observatory in northern Chile, and is the World’s largest survay telescope.
Read more about the images here
and read more about VISTA here
That isn’t an explosion … THIS is an explosion!
Astronomers working with the ESO’s Very Large telescope (VLT) have made detailed observations on a supernova.
Supernovae, the final explosions for dying high mass stars, are relativity common in the universe with at least one occurring somewhere in the universe every second, this figure may be an underestiate on the true number of supernovae as the figure could be closer to 3 suaernovae per second!
Despite their apparent frequency supernovae generally occur rarely in any one particular galaxy with long gaps in between bursts. This is not always the case though particularly in starburst galaxies in which large numbers of high mass stars are created and die in a short period of time.
These new observations are for SN 1987A and allow us to see the debris in a way never before achieved – in 3D.
The video below shows the structure of the debris in wonderful detail. This is an ESO video and more information on it can be found here.
The video shows everything from the outer most layers of the explosion moving in closer and closer towards the centre becoming a more and more hostile place as it does.
In fact it is the innermost area of this supernova that is particularly interesting. As can be seen near the end of the video, the central debris is deformed and unsymmetrical - it bulges out more in one direction than the others.
This kind of detail is only possible to obtain as the VLT has such high resolution and the supernova’s relative proximity to the Earth. At ‘only’ 168,000 light years at the edge of the Tarantula nebula in the Large Magellanic Cloud, it is the closest observed supernova since the invention of the telescope and was first observed as its name suggests in 1987.
The new observations allow astronomers to conclude that the supernova was more powerful in one direction - hence the outward bulge. This agrees with the more recent computer models on the development of supernovae explosions. However the direction of the bulge disagrees with the what the models expect in relation to the other debris so it seems the models aren’t perfect just yet.
Another interesting fact about this supernova is that it was the first to have been preceded by a detectable neutrino radiation pulse. Neutrinos are a type of subatomic particle and are produced in HUGE numbers at the very start of a supernova. Models predict that as much as 99% of a supernova’s energy can be released in a neutrino surge. The first detection of such an event bodes well for this theory.
A final interesting anomaly with this supernova is that its missing its neutron star. As star that created the supernova is believed to have been a B3 supergiant, the result of the supernova should have been a a neutron star but as of yet no such object has been detected. A number of ideas have been put forward, one is that the neutron star is there but is shrouded too deeply in gas and dust for us to detect it. The second idea is that enough matter fell back onto the neutron star after the supernova that it further collapsed into a black hole hence its absence. The third idea is that the star collapsed into a more exotic for of star – a quark star.
For the moment it is impossible to know which one of these ideas is correct or even if any of them are! Hopefully one day we will reveal all this explosion’s secrets.
