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


  • 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.


  • 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 ( 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

    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

    "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...