Thomas Barrett

Thomas Barrett

Research Fellow in Space Sciences.

I work mainly on volatile elements, their abundance and isotopic composition in meteorites. Also beginning a journey into instrument development for space missions.

Location Milton Keynes

Activity

  • Really great seeing everyone engage with this task! :)

    Just to make sure I join in here is mine
    Name: Deneb
    Constellation: Cygnus
    Distance from Earth (light years): 2,620
    Mass: 19 +/- 4 Solar Masses (mass of our sun).

    Info: Brightest star in the Cygnus constellation, 19th in the night sky and a blue-white supergiant. It is also one of the first only...

  • @KarenWells That is a very broad question and one that can be quite difficult to answer. Mostly, things follow the rules that we have observed and can predict. There are, however, sometimes special circumstances where the normal rules may not apply. When we observe these it shows us we need to re-evaluate the rules we have set out for ourselves but also work...

  • @AlysonKelman that is a fair point, however, I think that relative to the rest of the solar system and interstellar space we have been pretty stable.

    Mars daily average temperature variations can reach almost 150 degrees C difference between day and night. The difference between the estimated global average temperature of snowball earth (-50 C) to the...

  • Good :) Glad it has helped.

  • Glad to help :)

  • When the samples you look at in the lab are 4.5 BILLION years old it kinda is :P

  • I am sure there are experiments that look at dust and how it clumps in a vacuum (I am pretty sure there are people in my department doing similar things with ice and dust).

    Areas of higher density means there is more chance for dust to bump into each other and stick. Remember these processes take a very very long time. Once there are enough dust clumps...

  • It's great to see everyone engaging with each other and sharing their thoughts and experiences.

  • @DougKaro
    1. So as far as my understanding goes. Plutonium is the heaviest naturally occuring element, however, this is created when uranium caputres neutrons rather than in star processes. Which means that the text is correct, stars can fuse up to uranium. I can think about how to word this better next time however.

  • We all hope for good weather!

  • In response to 1:
    This is not entirely correct. Stars can fuse all the way up to Iron 56 anything heavier than this is not possible and only the biggest stars can get up to elements like iron and nickle. There is a process call the s-process (or slow process) that isn't fusion that can form elements such as Strontium. The S-process works by neutron capture...

  • Cacluations have told us the mass of the sun and observations allow us have a good idea of the composition of the sun. From this we can then know how much H is left in the sun.

    Calculating the lifetime is then a job of looking at how much H is left and how quickly we are using it up. Like knowing the miles per gallon of petrol for your car.

    For...

  • These images are almost always false-colour so the colour seen is not real and correlates with something else (e.g. Temperature). I imagine that the reason the information is not supplied (though I will look into it) is that each images conditions are different to each other and it is possible that the conditions were not specified where we got the images from...

  • The X-rays come from hot gas orbiting around the black hole in an accretion disk. As the gas orbits, magnetic stresses cause it to lose energy and angular momentum, thus spiralling slowly in towards the black hole. The orbital energy is transformed into thermal energy, heating up the gas to millions of degrees, so it then emits blackbody radiation in the X-ray...

  • Cloudy days are the bane of astronomers lives! Hopefully there will be a window within which you can see the night sky during the course!

  • Hope you have all enjoyed the first week of the MOOC learning a little about the Origins of Orion!

    Next week - Stars! and how they change over their lifetime.

  • And this technology is not the cutting edge! Usually the most advanced bits of kit we have are large and very sensitive to change. It takes a fair amount to time to make them small enough and rugged enough to survive space with the same performace.

    I was speaking to someone at a confernce yesterday and they said something like several of our instruments in...

  • I'm really happy the OU managed to get him to do these. They really are get little bite sized chunks of knowledge.

  • Hey @JimFortis
    If you are talking about how long the mission will last. Gaia launched in 2013 and will operate till about 2022 with enough fuel for an extended mission till 2024 if funding approved.

  • Really enjoying everyones constellations! Great imaginations everyone :)

  • That is really unfortunate. Light pollution, paricularly in cities is a real problem for this. If you have the opportunity to go somewhere with a little less light pollution you hopefully will have a better time.

  • Ok looking at the video you are staying in the same plane (so no up or down movement) and slowly moving around Orion which remains fixed. The camera zooms in and out at points to accomodate the distance between the stars. Looks like you do one full rotation of Orion.

    What the video has done is similar to if you walked anti-clockwise around a fixed sculpture...

  • Thank you for the feedback. If I can find out who made the video and if they have a reference frame I will get this added (thought it might not be for this presentation of the course)

  • I very much understand. The cultures that came up with their own constellations likely based them on the brighter stars they could see with the naked eye and as you will know from Section 1.7 their mythology.

    In Section 1.13 you can come up with your own constellation! So you won't have any knowledge of what you are looking for. Just your imagination :)

  • Yes the dust is likely to be silicate (SiO2) dust so a combination of both elements. Silicate material (things made up of SiO2) is also the building blocks of most major rock forming minerals on planets.

  • The closest thing I know to the software you are on about is universe sandbox (http://universesandbox.com/) but that is more creating star systems and seeing what happenes.

    I am positive there must be something out there. There is a very big galaxy map in the video game Elite Dangerous (Space Simulator) where you could fly to another star system and then...

  • Glad you find it clear. If you want to make sure your maths is ok write out the example in the video and see if you can get to the same answer without playing the video again.

    This is what I do whenever I need to do some new maths for my research. Find someone who has done it before, get an example from them, copy it out and then do it myself till I get...

  • Hey @RichardPacific thank you for the interst.

    Most of what I have learned about the subject has come from academic papers, which can be hidden behind pay access. It feels a bit cheeky but I wrote a paper on part of this subject that is open access (so free to all) if you wanted to read that....

  • Sadly the weather is what gets us all! This is why astronomers end up putting their telescopes in places like the Atacama desert in Chile, clearer skies and less atmospheric distortion.

  • It is 640 light years from what I can find. Whilst we expect that Betelgeuse has a fair amount of time left in its lifespan based on where we believe it to be in its evolution (see Section 2.12 for more), it would be incredible to witness the supernova first hand and collect data on it.

  • Hey Mic. From what I can gather the brightness changes are related to pulsations in its outer layers. However, the appearance and disappearance of large convection cells on its surface may also influence the brightness changes seen. So my guess would be fluctuations in temperature and possibly size. As to why this happens on this kind of 6 year period I am not...

  • I would also like to point out that some links to OpenLearn (e.g. in Section 1.5 Finding Orion) may also have a red box when you get to the page hat highlights the video has not been updated in a while. This is part of OpenLearn's archiving policy.

    It is there to remind you that for videos that contain scientific content, advances may have made that have...

  • Thomas Barrett made a comment

    For those of you who follow the OpenLearn link may be greeted with a red box that highlights the video has not been updated in a while. Don't worry it is still accurate it is just the university's policy regarding archiving content.

    It is there to remind you that for videos that contain scientific content, advances may have made that have changed our...

  • For those of you who have seen that Betelgeuse has been dimming more than usual in the news. I have pinned a comment to the section 2.3 Luminosity of a Star that addresses this matter a little and provided some additional reading.

  • You may be aware from the news that the star Betelgeuse in Orion has been uncharacteristically dim recently. This star is classed as variable and has a roughly 6 year cycle where it gets brighter an darker. Whilst the scientific community would love to witness Betelgeuse go supernova and get to study the phenomena first hand it is unlikely that is what is...

  • Thomas Barrett made a comment

    Hello all!
    Hope you have all had a good new year and welcome to the MOOC!
    If there are any questions or comments please direct them to myself or the course facilitators Helen and Sam (links to their profile and mine are in the main body of text here should you wish to follow us). We are happy to help and here to hopefully spark some great discussions between...

  • Just want to give a big thank you to everyone who has participated in this MOOC. We have had some fantastic comments, brilliant questions and great debates.

    If you have enjoyed this MOOC please consider another of the Open Universities MOOCs such as "Moons" or maybe even an OU course http://www.open.ac.uk/courses/

    Thanks once again :)

  • Thanks @LindaBaldwin I will have to see if I can find it. Sounds interesting :)

  • That is because the easiest type of life we can look for is similar to ourselves. As far as I am aware life as we know it requires liquid water in some way, therefore, looking for liquid water is our best shot at finding life at the moment.

    It is entirely possible that life exists that does not require water, but we would have no idea how to look for it...

  • From work on metoerites we know that their were planetesimals around our Sun as early as a few million years after its formation.

  • A quick wiki reveals:

    A proplyd, a syllabic abbreviation of an ionized protoplanetary disk, is an externally illuminated photoevaporating disk around a young star. Nearly 180 proplyds have been discovered in the Orion Nebula. Images of proplyds in other star-forming regions are rare, while Orion is the only region with a large known sample due to its...

  • So I did some digging and found this. Full Credit to this person here
    https://astronomy.stackexchange.com/users/5264/pela

    "Yes indeed, the Sun (and other stars) has an oscillatory velocity perpendicular to the galactic plane. According to this Nature article, the Sun crosses the galactic plane roughly every 30 million years, reaching a max height of...

  • @GrahamWomack Good idea!

  • I imagine it would depend of the gravitational interactions between the stars. If the dust and gas required to form a planet was not hugely disrupted by two or more stars then yes a planet could form. How long the planet survives would again depend on how it interacts with the multiple stars (and that is quite a bit of complex maths!).

    We do know of some...

  • Quite a few and there were more in the past that have now been terminated! (some of which are still probably in 'graveyard orbits' so technically still in space just not operating)

    Many also have multiple instruments on them e.g. the NASA Swift Telescope has three different...

  • If you are talking about the literal "Very Large Telescope" (VLT) is in Chile and there is only one installation (but four different types of telescope at teh same place). You are, however, right that if different telescopes around the world can observe the same event with similar instruments you can triangulate.

    Additional...

  • Thomas Barrett made a comment

    I used to take part in Galaxy Zoo a little while back. It really is fun and has been useful to the scientific community!

  • @PaulWatson 'Milkdromeda'! Nice might have to use that when I give a talk :) (with proper referencing ofc)

  • So from some quick research it seems the best way people have for determining the age of the Milky Way is to look for really old stars and other stellar objects (such as globular clusters) and age date these with long-live radioisotopes in a technique called nucleocosmochronology (from the words nuclear, cosmos and chronology; so nuclear space time).
    The...

  • I do like the scene where the aliens are playing marbles with whole galaxies/universes.

  • This is 8.2 billion years in the future. Andromeda and the Milky Way are not expected to merge for another 5 billion years or so (00:46 seconds in to the video).

  • Dark Matter and Dark Energy are still technically hypothetical. Their existence is implied by some observations and because some calculations don't work without "something" else being out there. Their exact nature is still rather contentious but Dark Matter is thought to be up to 85 % of all the matter in the universe.

  • @JanCantle As the links at the end of each section are typically additional material for those who are interested (and I am obviously very glad to hear you are interested) they may not be factored into the three hours per week the course recommends. I shall speak to the original designer of the course and try to find out.

    I see the suggested time spent on...

  • If you are interested in learning more the Open University has quite a few options from a certificate all the way up to degrees.

    Link to the certificate qualification.
    http://www.open.ac.uk/courses/qualifications/s20

  • What was around before the big bang is still up for significant debate. The best answer currently is we don't really know.

    There is a decent New York Times Article I have skimmed through that seems to give a little more information
    https://www.nytimes.com/2001/05/22/science/before-the-big-bang-there-was-what.html

  • Essentially this all comes down to the First Law of Thermodynamics which essentially states you cant destroy or create new matter, only change its state. This has been pretty rigorously tested as we don't see the laws of physics changing over time.

  • You are most welcome :) It's really heartening to see so much interaction between learners as well!

  • It is just to give you some visualisation of what a neutron star (pulsar) looks like with its fast rotation and radiation emissions from near the poles.

  • The reaction you are suggesting isn't a fusion reaction so wouldn't release energy like H-burning or He-burning do. Also certain reactions are only stable under certain pressures and temperatures so i'd imagine its far too hot and pressurised to make CO2 in that way.

  • Dear @AndréSkjeggedal we appreciate your passion and thank you identifying an area that can be updated. Wherever possible we aim to continue updating the course and respond to learners comments. We have now amended the text as appropriate, a quick bit of research puts the number at ~ 54 galaxies in the local group.

  • @GuilhermeLetsch is correct. 0 K is the coldest anything can be in the universe. Negative numbers in Celsius are still positive in Kelvin (e.g. -10 degree Celsius = 263.15 kelvin)

    There are many conversion websites (or apps) that can help. For example:
    http://www.onlineconversion.com/temperature.htm

  • Thank you for the feedback @RobBolton . I am very glad you are really enjoying it! If possible I will look into how long the majority of people take per week to complete and update the estimate. I'm not sure if that data is collected.

  • Yes, everything you see around you (including yourself) is made of stardust!

  • We may never know but it is always good to imagine :) and, personally, I have no idea what you would see. It could be that you just see the same kind of space you do here, as all you are changing is your reference point for the observable universe.

  • The Shrek quote of an onion has many layers always comes to mind these days :)

  • If you remember the previous sections video the crab nebula supervoae was so bright it could be seen during daylight. Chinese astronomers called stars that appear temporarily in the sky "guest stars" (kè xīng 客星). This was well before the era of modern telescopes so my assumption is it was seen with the naked eye (or rudimentary tools).

  • Hey @PhilGamlen
    First up there are no daft questions only silly answers. As you contract you increase the pressure and pressure and temperature are linked
    "For a fixed mass of gas, at a constant volume, the pressure (p) is directly proportional to the absolute temperature (T)."
    As we are not only increasing the pressure by squashing things together you are...

  • The Mass-luminosity relation can be determined empirically by finding the mass of stars in binary systems of a know distance. When we have plotted enough stars the slope of the log graph produces the power factor 4 (for main sequence starts; a more accurate number is 3.5 but makes the maths significantly more complicated to imagine).

    The derivation of the...

  • Darn :( Let's hope for clear skies soon then!

  • As far as I am aware yes. I don't know of another way for the dust and gas to collapse and form a star.

  • @AshmeadA
    The light produced from a distant star can take a long time reach us. As we can only observe the star once that light has arrived at us we are kind of looking "into the past" as the star could have changed in the meantime and it would take the same amount of time for us to find out. That is why observing stars that are very far away can allow us to...

  • @LLynDeDanaan I posted a message in the "Share your Image" saying the problem with Padlet should have been resolved. As for Stellarium, I believe our facilitators have pointed out alternatives. I shall see if we can do anything about Stellarium.

    Regarding adding additional cultures, I only inherited this course a few weeks before it started so have not...

  • The birth of the first stars is actually something that is an ongoing research area. One idea is that these first stars again formed from dust and gas, albeit just hotter, and this dust and gas would have been created during the big bag. So yes they would be from something just after the particle soup of the big bang @PhilGamlen . After these stars died, some...

  • It is actually rather tricky to estimate the age of stars. It seems that spectral luminosity is one method used to estimate age when you use it along with the Hertzsprung–Russell diagram (which depicts the typical evolution of a star). We can spot young stars as they might have protoplanetary disks around them which means their planets have not had time to...

  • Now we are getting into relativity here @AshmeadA . From scientists like Einstein we know that space and time are inter-linked and gravity can affect spacetime. Something like a black hole, an object so dense and gravitationally strong that even light can't escape warps spacetime significantly more than say a planet. If you were near a black hole, but not...

  • Ok that is a very good question, and something I hadn't actually considered. First off, we know from experiments and observations that the speed of light in vacuum is constant wherever you are in the universe. As the year is a human concept anyway we are applying our understanding of time (and being vain so its all relative to an earth year) to a speed, then...

  • Just to be clear the colours in that image are unfortunately not the ones you'd see with the naked eye (but they are part of the nebula in a way). Scientists here are using what is called False Colouring, basically what they are doing is taken things we have recorded but can't see visibly (in these cases it is usually part of the electromagnetic spectrum) and...

  • I always think of the Father Ted sketch where Ted is trying to explain to Dougal "these cows are small.....those are far away"

  • This is down to what is called the critical point. Beyond the critical point you can't compress the gas into a liquid. Also temperature will likely have an effect on this, the star too hot for liquid to form. There are phase diagrams for H and He which you can look at which help show this (though they are a little complicated to read).

    Link for reference....

  • Have made my first upload to the Padlet of Orion from my Pixel 3. Doesn't look too bad considering there is a street light at the bottom of Orion! I am seeing some lovely photos from everyone else. Keep it up!

  • So we know the age of the universe is roughly 13.7 billion years old and that electromagnetic radiation (light, radio waves, microwaves etc.) travel at the speed of light.
    With that in mind if we had a really powerful telescope the furthest we could see would be 13.7 billion light years in all directions (1 light year for every year the universe has existed;...

  • Thank you for your comment. Indeed the Polynesians are famed for their navigation of the Pacific. In this activity we are, however, merely demonstrating here how you yourself can find north (or south) and your latitude and longitude.

    Discussion of famous navigating cultures is, of course, welcomed here in the discussion section.

  • I have spoken to the maintenance team and they tell me that you should be able to upload again.

    Thank you for your patience.

  • I have spoken to the maintenance team and they tell me that you should be able to upload again.

    Thank you for your patience.

  • Hey all,

    If you are having trouble uploading images to the Padlet I would suggest sharing your images via the Twitter hashtag if you can. The MOOC maintenance team have been contacted and we are hoping to get this resolved soon. Apologies for the inconvenience.

  • Keep going at it! How many can you remember currently?

  • That is really interesting. Thanks for sharing. Does anyone else have any other interpretations of Orion, or parts of Orion, that are native to their region?

  • There are some great images on the Padlet. Well done everyone. Now lets how Orion moves through the night sky during the course!

  • Thomas Barrett made a comment

    I would be interested to know how peoples more modern camera phones are doing at taking photos of Orion throughout the course. Mobile cameras have made quite the leap since this was first written in only a few years. I am going to try to try this activity with my new Google Pixel 3 and report back.

  • That's really good! I managed to catch a glimpse of it here but it was a little cloudier than I was expecting!

  • Great to hear you have been part of the OU community before Alan! I can imagine Aberdeenshire is very beautiful at this time of year. As a far of the cold I am not sure that would bother me too much :) Please tell us all how your Telescope observations go!

  • Thomas Barrett made a comment

    It's a lovely clear day here at the OU Campus and supposed to be a clear night too! Hopefully it will be clear night for everyone as well.

  • Thomas Barrett replied to [Learner left FutureLearn]

    That's interesting as my family and I have always thought of a 'saucepan handle' to be part of The Plough/Big Dipper (itself a part of the larger constellation Ursa Major). Anyone else have interesting names for parts of constellations?

  • I think working as a group will be really fun. I find that it is always easier to learn when you have people to discuss with!

  • Thomas Barrett made a comment

    Hello all!
    In case you missed my post in the welcome discussion I want to make sure you are all aware of myself and the two facilitators. This is my first time as lead educator for this course, taking over from my supervisor Monica so I am excited to get started with you all. If there are any questions or comments please direct them to myself or the course...

  • Edited for clarity. Working long hours fries my ability to type.

  • Its very difficult. My housemate works on this for his PhD. He spends a lot of time doing just that! I have no idea of his method however.

  • It takes a lot of thought to work out if a star has more than one planet - especially if they transit at similar times to each other - is it one planet with a fast orbit or two planets? As I am not an astronomer I can't tell you exactly how it is done by my housemate looks at Exoplanets and he spends a lot of his time looking at transits and trying to work out...

  • Its as the star subtle moves closer or away from us as we rotate. We cover Doppler shift in week 3 I believe.

  • Well however far fetched it is NASA are looking into warp drives
    http://io9.com/heres-nasas-new-design-for-a-warp-drive-ship-1588948192

    So getting there may not be as difficult as we previously thought (assuming it works). If it doesn't then I assume to get there it would be a similar "Noah's Ark" kind of approach and just accept it will be generations...