Episode 16: Transit of Mercury, 11 November 2019
with Dr Niruj Ramanujam
DO NOT LOOK DIRECTLY AT THE SUN THROUGH A TELESCOPE OR WITH YOUR NAKED EYES DURING THE TRANSIT OF MERCURY OR ANY OTHER TIME!
On the 11th of November 2019, the planet Mercury will pass between Earth and the Sun. This transit of Mercury will be visible across all of Africa by simply using a small telescope.
In this special episode, we speak with Dr Niruj Ramanujam from the South African Radio Astronomy Observatory (SARAO) about the importance of these events and how you can see the transit.
It will take the planet 5.5 hours to move completely across the disc of the Sun, starting at 14:35 SAST. The Sun will set before the transit ends, depending on your location (Sunset in Johannesburg will be at 18:31 and Cape Town at 19:23)
Transits like these are rare as Mercury’s orbit is at an angle to that of the Earth’s. The last time Mercury transited the Sun was in May 2016 and the next one will only be on 13th November 2032.
Please note, that in order to see the transit you must take serious precautions. You can watch Mercury transit the Sun, but YOU MUST BE CAREFUL!
How to observe:
Firstly, you will need a telescope (a small one with metal (not plastic) parts will do). You will not be able to use binoculars as they are not powerful enough.
Secondly, you will need a sheet of clean paper on which to project the image of the Sun through the telescope.
DO NOT LOOK DIRECTLY AT THE SUN THROUGH A TELESCOPE OR WITH YOUR NAKED EYES
Doing so will cause permanent damage and possible blindness. Only look at the transit indirectly by looking at the projection on paper. This is the safest way to observe the event.
The handbook, which is available below, provides guidelines to safely observe the transit of Mercury.
Contact your nearest university, science centre or amateur astronomy club to locate the nearest venue where you can see the transit safely.
Where to view in Cape Town
The South African Astronomical Observatory
1 Observatory Road
Start time: 14:15
End Time: 17:00
Eden on the Bay Mall
GPS: 33° 47´ 34.51″ S; 18° 27´ 32.32″ E
Cnr Sir David Baird Dr &, Otto du Plessis Dr,
Start time: 14:15
End time: Late, until after Sunset for some planetary viewing.
If you have a telescope and would like to host an event please complete the following form:
Details from your location: https://www.timeanddate.com/eclipse/map/2019-november-11
This week’s guest:
Transit of Mercury, 9 May 2016, photographed by Elijah Mathews. The sharp dot left and below the centre is Mercury and the fuzzy spot higher up is a sunspot .
Dan: [00:00:00] Welcome to the Cosmic Savannah with Dr. Daniel Cunnama.
Jacinta: [00:00:08] And Dr. Jacinta Delhaize. Each episode we will be giving you a behind-the-scenes. Look at world class astronomy and astrophysics happening under African Skies.
Dan: [00:00:16] Let us introduce you to the people involved, the technology we use, the exciting work we do and the fascinating discoveries we make.
Jacinta: [00:00:23] Sit back and relax as we take you on a safari through the skies.
Dan: [00:00:36] Alright, so we have a special event.
Jacinta: [00:00:39] Yes, welcome to episode 16. We usually release an episode every fortnight, but we’re going to make an exception this time after one week because we want to release this on time for…
Dan: [00:00:49] The transit of mercury!
Jacinta: [00:00:50] Yes.
Dan: [00:00:51] What is a transit?
Jacinta: [00:00:52] It is when a object goes between us on the Earth and the Sun.
When’s this transit going to be?
Dan: [00:00:58] So on the 11th of November this year 2019 visible over most of Africa, Mercury will pass between the Earth and the Sun. We’ll be able to see a tiny little dot moving in front of the Sun. Not with your naked eye. Don’t look at the sun with your naked eye.
Jacinta: [00:01:13] Don’t look at the sun!
Dan: [00:01:15] Don’t look at the sun full stop. Especially don’t look the through binoculars in case you’re tempted you will not be able to make out Mercury. It’s very very small only a few thousand kilometers across so a hundred-and-ninetieth the size of the Sun so you really wouldn’t be able to see it. Anyway, even if you had a eclipse glasses or something like that, so if you would like to see the transit of mercury visit your local Observatory or observing group where they will have the correct equipment and you can have a look there.
So now that that’s said. I did speak to Dr. Niruj Ramanujam who is a commissioning scientist at the South African Radio Astronomy Observatory, but he is also an avid outreacher.
And he is coordinating the transit of mercury events across Africa and trying to get as many telescopes as possible looking at the transit in a safe way. So we spoke to him about what this means and how you can best observe this exciting event.
Jacinta: [00:02:16] And yeah, he goes into a lot of details. So let’s just hear all about the transit from Niruj.
Dan: [00:02:22] Today we’re joined in the studio by Dr. Niruj Ramanujam. So Niruj is from the South African Radio Astronomy Observatory – SARAO, and the public Outreach and Education Committee of the Astronomical Society of India of which he is a member. Welcome to the Cosmic Savannah Niruj
Niruj: [00:02:46] Thank you. Thanks. Thanks
Dan: [00:02:48] Before we get into it, can you tell us a little bit about yourself and how you came to be here in South Africa.
Niruj: [00:02:53] So I’m a radio astronomer by training and before this I was in India working for the National Center for Radio Astrophysics, which runs a telescope a bit similar to MeerKAT here called the GMRT. I’ve also been involved in astronomy outreach and education for many years when I was there.
And at some point I like to keep changing countries. I like to move around. I guess that’s that’s the that’s how astronomers are and therefore I thought I’ve been to South Africa few times before for visits for work. And when this opportunity came up, I thought it’d be a nice place to come and spend some few years here. So here I am.
Dan: [00:03:30] So how long have you been here?
Niruj: [00:03:32] Five months, so it’s been fairly new.
Dan: [00:03:34] And what exactly are you doing at SARAO?
Niruj: [00:03:36] I’m a commissioning scientist. Which means that I look at data coming in from the meerkat telescope and look at the data from the point of view of an astronomer and try and figure out if the data is fine.
If it’s not good then what’s wrong with it and the fact that I’m an astronomer by training helps in the sense that I know what the sky should look like a how the data should look like and therefore we look at sources we already know well, we look at objects in the universe we know well already from previous observations from other telescopes.
And therefore we use that knowledge to debug the telescope if you wish so that it can become much better at what it does and therefore other astronomers can come in and use it to do the science. They want to do.
Dan: [00:04:18] And we’re getting there with Meerkat, right?
Niruj: [00:04:19] Yes.
Dan: [00:04:20] Great. So we’re not here to talk about that today. Although it’s very interesting. We have spoken about meerkat a lot in the past.
Today we’re here to talk about a very exciting event happening on the 11th of November.
Niruj: [00:04:33] Yes, this year
Dan: [00:04:35] This year, in 2019, a transit of mercury. So what exactly is a transit?
Niruj: [00:04:41] Right. So I think all of us know eclipses right, the Sun and the Earth and the moon if they aligned in a straight line if the moon comes between us and the Sun and hides the sun you have a solar eclipse. If the Earth comes between the Moon and the Sun and hides the moon or a shadow falls on the moon then we have a lunar eclipse. These are fairly well known and because the Moon is so big in the sky it can cover the entire sun, right. Now if you look at what other objects can come between us and the sun in the solar system. The only two other planets are Mercury and Venus because they are the ones whose orbits are within the Earth’s orbit.
Now therefore if the paths, if the orbits align correctly which happens every few years, then you could expect Mercury or Venus to come exactly between us and the sun in which case if you’re looking at the sun’s image carefully you will see Mercury or Venus go past the sun’s disk. Much like for example, you know, if you look at the setting sun you might find that seabirds or aeroplane passing in front of it the same way.
You would find Mercury or Venus passing in front of it. It would of course take a few hours for either of these planets to go in front of it. And what we’re going to have on 11 November is the transit of Mercury. Where you going to see Mercury take around five and a half hours to pass across the face of the Sun as seen from Earth.
Dan: [00:06:00] You mentioned that these events happen every few years how frequently do they occur?
Niruj: [00:06:06] Okay, so they don’t occur at regular intervals because you had to consider the time it takes for Mercury to go around the Sun, the time it takes the Earth to go around the Sun, and then the orbits are inclined with respect to each other and therefore they don’t align in regular intervals.
For example, the last Mercury Transit which was seen from Earth was in 2016 in May. And the next one will be seen from Earth and will be visible from Africa as well as in 2032. So the Mercury Transit there’s a pattern to when it occurs, but they’re not every few years, right? So it could occur, the November transits could occur every 7, 13 or 33 years and the May transits could occur 13 or 33 years.
So there is a pattern to it, but this is not periodic. So the next one will be in 2032. The previous one was in 2016.
Dan: [00:06:56] And why are they occurring in May and November?
Niruj: [00:06:58] So that’s interesting. If you look at the solar system as a 3D model the earth goes around the Sun in an orbit, which is in a plane, right, you can define a surface in which it goes on. Mercury goes round the Sun as well, but it’s plane of orbit is inclined to the Earth plane of orbit, but on seven degrees.
Dan: [00:07:14] Okay.
Niruj: [00:07:15] Now if you imagine two gigantic sheets of paper, if they intersect they would intersect along a line. And therefore when Mercury and Earth are on the same end of this one line is when you get a transit. And if you look at which months of the year does mercury, and therefore as seen from the Earth, the Sun, come on to this line, which is the intersection of the two orbits, it’s either in May or November. Okay. It’s a bit similar to why we do not get a lunar or a solar eclipse every full moon on new moon. But only every now and then when the exactly match it’s the same principle as why we have Transit of Mercury and Venus only every so many years and why occur on certain months. On certain days.
Dan: [00:08:04] In terms of these transits I know that here right here at the the observatory in Cape Town back in 1868 on the 4th of November, there was a Transit of mercury observed from this sight. In terms of astronomy why are these transits important and what is there to be gained from observing a Transit as an astronomer?
Niruj: [00:08:26] Oh, I’m happy you asked the question because that’s what excites me about the transit of Mercury apart from the fact that it’s a beautiful sight. I myself saw a Transit of mercury when I was in high school in India, and it was it was lovely. So I knew exactly when it was going to come into the come across a sun and I was waiting with my friends and then one of us saw it first and you’re very excited and then we could follow it.
We mark the spot on the piece of paper every half an hour. You could see the planet moving like we kind of look at the sky or we look at the sky chart or you read the news and you’re you know, the planets go around the Sun you read about Kepler’s laws and Newton’s law of gravity. But this is an occasion where you can actually see a planet moving, you know, every few minutes you can see it move little moving in front of you and that’s that’s an amazing sight. You know, that’s really inspiring and motivating. I just want to add it in because I think the reason people should go and see the transit of mercury is you can actually see a planet moving, you know, around the Sun and I think that that’s really amazing.
Apart from that historically looking at transits of Mercury and Venus were incredibly important in astronomy. And this is for this reason. You might have studied Kepler’s laws in school. Basically Kepler kind of came up with laws of how the planets move around the sun. Right? And this is before Newton’s law of gravity. So it was based on observations now based on his laws people knew the relative distances between objects in the solar system. For example, people knew if you take the reference as the earth-sun distance, for example, people knew the Mercury-Sun distance as a fraction of the Earth-sun distance people knew the Jupiter-Sun distance as a fraction of Earth-sun distance and so on so all distances within the solar system, which if you remember if you if you recall 200 years ago a hundred years ago was the entire universe for them in some sense, were known relatively. Right.
So people knew if Earth-Sun distance was one meter. Of course, it’s not then Neptune-Sun distance was so many kilometers or whatever it is. Right, but people do not know what the absolute distance is where they did not know how big our solar system actually was and you know, and you can imagine this was one of the big questions in astronomy at the time because almost all astronomy was done within the solar system. The stars were known to be very very far away, but it was too far away to measure but people did not know how big the solar system was right until Kepler in 1631 predicted the first Transit of mercury, which was observed by Gassendi in Paris.
The second Transit of mercury was observed was by Shakerly from India in 1651. The third was observed in 1661 and the fourth was observed in 1677 by Edmund Halley himself of the Halley’s Comet fame and Newton’s great friend. Right. Now what Halley realized is that you could use the transit of Mercury and Venus.
If you time them accurately from many parts of the Earth at the same time, you could then use these measurements to to measure the actual absolute size of the solar system. It works in this way. It’s basically what we call triangulation, right? If you held out your finger in front of your face at arm’s length, and you close one eye and look at which far away object is your finger in front of.
And then you close the other eye and open the first eye and then look at which object is in front of you, it moves. Right? So you see the finger in front of different objects basically because you’re seeing it from different eyes, right? This is called parallax. The fancy word in astronomy is parallax.
Therefore if you know how far apart your eyes are which I’m sure you do and you know how long your arm is and therefore how far away your finger is, if you measure this angle you could in principle, you know, get other distances in this triangle and this is basically high school trigonometry and we use this in many many things we. Use it in surveying land, for example, the way we map out land is by triangulation right? You have a triangle you measure. You know one side and two angles you can get the third. This is the third point. Basically that’s what it is right.
Now Halley realized that the Earth is big enough that if you stand on two parts of the earth, very very far away. Let’s say a few thousand kilometers away. And you look at the path Mercury takes across the face of the sun, these parts are slightly different. Just as the the distant object in front of your finger appears different for different eyes in your head. Right? So imagine that your head is now the entire Earth the two left and right eyes are two spots, let’s say in Africa and Europe. And the finger is Mercury. And the distant object is the Sun.
So that’s exactly what it did. So he realized, he showed through calculation and published a paper saying look you can do the same thing on this grand astronomical scale. You can measure a triangle as big as our solar system. And if people in these two places measure the exact time Mercury entered the sun’s disc they could then measure the distance between the two eyes or the two observers on the earth and the finger which is Mercury right? And once you do that, then because you know the relative distances between all objects in the solar system, you can measure the absolute distance between any two objects in the solar system.
So that was a grand project of Halley. And therefore he then kind of appealed to all the European governments to do this measurement. Therefore every time there was a Transit of mercury or Venus anywhere visible on the earth, all countries like England, France and later US and so on would send astronomers across the Earth to measure the precise moment Mercury or Venus would enter the Sun’s face on the sky in order to measure the entire universe. And that is why transits have been historically important and in fact for 200 years the only method we had to measure the universe of that time was to measure the transit. Of course the unfortunate side of it is that these Grand Expeditions which were probably the first examples of International collaborative science experiments were made possible because of colonization therefore they had access to various parts of the world.
So that is true in South Africa too. For example a Transit of mercury was observed in Cape Town where we stand now in Observatory on 5th November 1868, from Grahamstown on 10 November 1894, and from Johannesburg on 14, November 1907. Right, they observed the transit of Mercury. The 1907 Mercury transit was also observed by European astronomers from the DRC and from Mauritius too. Because remember they’re doing it from across the globe.
Transits of Venus are a bit more easy to observe because Venus is larger in the sky the Mercury. And therefore there were a lot more expeditions. For example, the 1761 Transit of Venus, that is like so long back, Mason and Dixon observed it from the Concordia Gardens, which is behind st. Mary’s Church in Cape Town. Right and the 1882 Transit of Venus was observed by many in many locations.
So England and the U.S. sent astronomers, along with the European origin astronomers in South Africa, to many locations in South Africa. So they observed it from of course the Royal Observatory of Cape Town, which is the present SAAO, also the Natal Observatory in Durban in Touwsrivier Aberdeen Road Wellington Worcester Matjiesfontein Beaufort West. And so on right and some of the telescopes they brought to South Africa to observe these transits are still in use in this Observatory including the six-inch grub equatorial Mount equatorial telescope and so on. Until you know till late 1800s or the early 1900s when we developed other methods of measuring distances accurately.
This was the only method available and at that time when people start measuring the distances to nearby Stars, they based it on the knowledge of the distances within the solar system. So, in fact these Transit measurements were used to build as it were a ladder. Or a scaffolding to measure distances out to nearby stars and then to far away stars and the whole galaxy. Now we have independent ways of doing at accurately. But at that time this was the building block to measure the entire Cosmos.
Dan: [00:16:48] So essentially calibrating the universe based on a Transit of Mercury.
Niruj: [00:16:52] Exactly exactly and in fact, this 11th November Transit if you were to time the transit start, let’s say from Somalia and Senegal, you would find a difference of timing of roughly one-and-a-half minutes.
Okay, and is this one and a half minute difference that astronomers tried to measure for 200 years, right? And if we have really good telescope a professional telescope or amateur telescope with computer controlled, you know drive and so on in the eastern part of Africa and western part of Africa, then should say hello to each other collaborate.
Time the transit of mercury and the difference is like a minute and a half which you can easily measure these days with your clocks and then you can yourself measure the distances between the Earth and the Sun Earth and Jupiter and so on yourself on the 11th of November.
Dan: [00:17:43] Which would be an amazing school or university project.
Niruj: [00:17:44] Exactly. Exactly.
Dan: [00:17:46] Very cool. I actually pulled out the the monthly notices of the Royal Astronomical Society book from 1868 the other day to have a look at the paper.
Niruj: [00:17:57] It was by this guy called Mann.
Dan: [00:17:59] William Mann yeah because I wanted to see what telescope they used and whether it was still here. It is still here. Yeah, it’s pretty cool.
Niruj: [00:18:09] So Mercury transits and Venus transits therefore have historical importance and I hope that some universities would make this measurement again on 11th of November across Africa because it is in some sense. It’s also very nice to imagine that it’s only by collaborating across countries that you can measure the cosmos, right. And by yourself you cannot do much. It’s only by talking to astronomers who are in totally different countries in different cultures speaking different languages, but using the same tools of science that you can do something as profound as measuring the entire universe.
Dan: [00:18:44] Astronomy really is the best science. And in terms of what you can see for the transit of mercury obviously Mercury is a lot smaller than the sun or or even the moon when it’s projected onto the Sun so for an eclipse the moon and the sun are roughly the same size which is why we get an eclipse, but for mercury, it’s certainly not the same size.
Niruj: [00:19:10] Yes. So this Transit on 11th November Mercury is going to be around 190 times smaller than the sun as seen on the sky. Okay. This is going to be a really really small dot.
Which is why if you want to see this Transit of mercury, you would need to magnify the Sun’s image in order to see this really small dot which is 190 times smaller. And the way you magnify the image, the Sun’s image is through a telescope. And therefore you need a telescope to magnify the Sun’s image to let’s say a foot or half a foot 30/20 centimeters big circle so that you can see Mercury going across the face of the sun clearly.
Dan: [00:19:50] So obviously you won’t be able to see it with the naked eye even through Eclipse viewers. Your eyes won’t be able to…
Niruj: [00:19:57] No you’re not. You would not be able to see it even to the eclipse glasses some of you might have. But at this point and I’m going to come back to this point again and again, let me say that you should never look at the sun with the naked eye anyway. Especially during a Mercury Transit. You might think it’s like an eclipse. Therefore, let me look at the sun directly. You should not do that. You cannot look at the sun through any optical device. You should never look at the sun any time of the day, or during this transit through any lens or binoculars or telescope at all. But there is a very very safe way of seeing the transit and I’ll talk about it.
Dan: [00:20:34] Absolutely. I mean, I think that’s something which we will definitely make a strong note of. We don’t want anyone to get damaged, anyone’s eyes to get ruined by this. This particular transit, when exactly does it kick off and you said it lasts about five hours. It’s on the 11th of November and the times?
Niruj: [00:20:53] So let me do the timings in South African time, which is SAST equivalently Central African time. And then I’ll talk about how it is in the rest of Africa as well. Now this Transit of mercury is special because it can be seen from all of Africa. So it’s an African Transit, if you will.
Right, Mercury is going to start entering the face of the sun on the sky at 2:35 p.m. 2:35 in the afternoon South African time. It’s going to take five and a half hours to go across the face of the sun and exit, right? The midpoint is going to be at 5:20/5:19 p.m. Right and the endpoint is going to be at 8:05 p.m.
Of course the Sun is going to set much before 8:05 p.m. And therefore you won’t be able to see the full Transit from South Africa. You would be… the sun sets in Cape Town around 7:23 p.m. And in Johannesburg around 6:30 p.m. Right so you’re going to be able to see a bit more than half the transit from South Africa a little bit more from the western part of South Africa compared to the eastern part of South Africa because as we know the sun sets later and later as you go more westwards, right?
But then because the sun sets later later as you go more westwards, the Eastern parts of Africa itself will see less of the transit compared to the western part of Africa and therefore if you are in for example, you know Ethiopia Somalia or one of those Eastern Parts you would be able to see the transit to a little before halfway through before the sun sets for you. But if you’re going to be on the western coast, let’s say now Guinea or Senegal you will see the entire Transit before the sun sets for you. But the important point is that wherever you are in Africa, you’re going to be seeing at least half the transit which is going to be around to two and a half hours, right?
So that’s why that’s why it’s a really nice event for African people to get us get together and and and see.
Dan: [00:22:49] Will there be events? I mean will there be telescopes around the continent for people to go and look because as you said you can’t look with binoculars, not by yourself. With eclipse viewers you won’t be able to see it.
So you’re going to need a telescope with a real solar filter in order for the public to see this. So this isn’t going to be a an easily visible thing to most most people they’re going to have to seek out some location where there’s a telescope set up particularly for this. Do you know if there are events planned around the continent?
Niruj: [00:23:24] So this is not something you can just go out and see for yourself. You need a telescope. But, you know, the telescope, how do you see the transit right? Remember you are looking at the sun. Some of us in high school have done this experiment where you know, you take a you take a magnifying glass, right? You take a convex lens from a Physics laboratory and then you focus the sun onto a piece of paper and within 5 Seconds what happens the piece of paper starts burning right. Now imagine that lends to be much bigger lens and your eye to be where the paper is. Your eye will melt and therefore it’s an incredibly dangerous thing tp look at the sun even for a fraction of a second through any optical telescope directly, right. The sun’s Rays as focused through any lens or mirror should never enter ever. It’ll it’ll cause you blindness or permanent damage.
Having said that, what we do, right, astronomers have been seeing the Sun for centuries. Galileo himself saw the sun through his telescope like what you do is that you make the telescope look at the Sun. You make sure the telescope has no plastic parts because the plastic is going to melt in the sun’s heat and then you focus the sun’s image onto a piece of paper kept, let’s say, half a meter from the eyepiece, right? And then you look at the image of the sun which is on the piece of paper. Now there are many advantages to doing so
One: This is completely safe. Because the sun’s rays are going to hit the piece of paper, but it’s going to be a focused large image. So the image would be 20 to 30 centimeters wide is not going to focus on to a point like when you’re burning a piece of paper and then you can you can look at the sun’s image very clearly.
In fact, this is exactly how using a pinhole camera by the way and later the telescope, you know, Galileo and others discovered sunspots on the sun surface. They discovered the sun rotates around its axis every roughly a month and so on so looking at the sun through projection, this is what we call the projection method you focus the sun’s image onto a large piece of paper kept a distance from the eyepiece and make it you know, and the farther away you move the paper the larger the sun’s image is the safe is a completely safe way to do it. As long as you make sure that while doing this focusing nobody gets in between the eye piece in the paper and look at the Sun by accident.
The other advantage of doing this for something like the transit of mercury is that this piece of paper is going to have an image of the sun which is let’s say 30 centimeters big. If you’re going to have a large public gathering of let’s say a hundred people, many people can look at the Mercury Transit at the same time. So it’s a public event, right?
Therefore, this is a very public way of looking at the transit together. If you some telescopes might have solar filters. These are special filters you put on the front of the telescope to block out enough Sun’s light that you can see through an eyepiece.
Now, we do not know how good your solar filter is going to be. We don’t know how old it is and what quality it’s going to be so we do not recommend that you use some solar filter you might have lying around. Therefore we recommend very very strongly that you only use the projection method to look at the Sun to look at the Mercury Transit on the face of the sun both because it is extremely safe and also because many people can see it at the same time.
Now having said that you might wonder how would I do this? Because I have no telescope or even if I have telescope I did not know how to point the sun safely. Therefore what we are what we are advising is that you go. You find a find amateur astronomy club or University or a school or a planetarium or a science center near you.
And you go pester them to organize a public event with the telescopes they have. Because they will know how to see the sun safely and show it to people safely. You go pester them to organize a public event for the transit of Mercury and make a public call. Let all of you your family your friends to go and see the transit of mercury with them.
Now what we are doing from our side. We are giving a public call to people with telescopes who know how to use them. It does include science centers and planetary amateur astronomers across South Africa and also Africa to tell us what telescopes they have and if they would be willing to organize a public event and we’re going to make a list of these public events. People are volunteering to organize and will make them public on a website and social media. So you can then look at that list and know if there’s something happening around you. But we also encourage you to go and you know, pester people like I said locally.
So who’s “we”? So in South Africa there are a bunch of us who do astronomy outreach and education and we are kind of trying to organize this across the country. SARAO where I’m from is is trying to do this with the nine countries involved in the SKA AVN. The square kilometre array Africa will be a network of partner countries. And to contact, you know, contact people we know there and see if and kind of work together to organize public events in all of these nine countries.
The African Astronomical Society – the AfAS, which was founded recently is also doing a similar exercise across all countries in Africa. So they are parallel efforts happening and we hope that there are quite a few events across the continent on 11th of November where you could go see the transit of mercury safely with your friends and family.
Dan: [00:28:37] Obviously here in Cape Town in particular they’ll be a few events going on. I know SAAO will be organizing an event.
Niruj: [00:28:44] Yes definitely
Dan: [00:28:45] And we’ll have details of all of these events available on the website and social media. So if you want to just follow us or also on the the podcast website will be there. We’ll make sure to post some details of where you can see if you want to get a access to a telescope.
Niruj. Thank you very much for joining us.
Niruj: [00:29:07] Thanks for having me. It’s been a pleasure.
Dan: [00:29:09] I think that I’m really looking forward to the transit. Yeah, we will certainly be letting you guys know about events that are happening keep an eye on the social media and on the website
Niruj: [00:29:20] And do pester your local University or Science Center with telescopes to organize a public event.
Dan: [00:29:26] Yeah or the amateur astronomers who
Niruj: [00:29:28] especially amateur astronomers
Dan: [00:29:29] are very knowledgeable about these things.
Niruj: [00:29:31] Yeah, and they’ve been doing this for a long time and they know exactly how to do it safely.
So again, let me end with saying. Make sure you’re safe when you’re seeing the Transit. Do not look at the sun directly through any Optical instrument at all during the transit or anytime else.
Dan: [00:29:48] Absolutely, I don’t think that can be stressed enough. We really don’t want somebody to lose an eye over this.
Niruj: [00:29:53] Exactly
Dan: [00:29:55] Niruj , thank you very much.
Niruj: [00:29:56] Thanks. Thanks a lot.
Dan: [00:30:03] Yeah, so, a very exciting event and it was great to speak to Niruj. The next one is only in 2032. So if you can try to see it, it will be great. I am actually going to try and live stream it from here at the observatory. I still need to try and set that up, but I’m trying to I’ll try and get it going on our Facebook live.
So if you do want to try and see it follow us The Cosmic Savannah we’ll be re tweeting and posting things. But also the SAAO just @SAAO on Twitter and we’ll send links as to where you can observe
Jacinta: [00:30:44] Super awesome. And can you actually see this Transit from any other continent?
Dan: [00:30:50] So very Southern Europe but mostly Africa.
Jacinta: [00:30:54] Oh really?
Dan: [00:30:54] It’s a true African Transit. Very exciting event.
Jacinta: [00:30:57] Yeah, that is very exciting. So I have to definitely take a look at that. I’m glad that you’re live streaming it. That’ll make it really easy to see and do you have any fun facts about Mercury?
Dan: [00:31:07] I know it’s incredibly hard to get to Mercury which is not what you’d expect.
There was about a year ago. There was this BepiColumbo Mission launched where they’re trying to go and send a couple of things into orbit around Mercury and I remember at the time not really understanding why it was so hard to get there because you think the sun is a massive gravity well and you can just fall in there, right?
But it’s actually not the case because the Earth is spinning very fast around the Sun orbiting very fast around the Sun. So what you got to do is slow this spaceship down a lot. So when you want to speed a spaceship up and you want to get it to Jupiter or Saturn or something like that, you do these gravity assists where you fly past a planet like Earth and you get a little bit of energy.
But what they’re doing with the BepiColombo is flying past the Earth and Venus and losing energy. So they’re using them to slow slow this this craft down, which I thought was quite cool. I thought it was something which I’d never really thought about.
Jacinta: [00:32:10] That is cool. That’s a really fun Fun Fact.
Dan: [00:32:12] Thanks.
Jacinta: [00:32:13] It’s a bit more fun than mine. Actually, my fun fact is that if you were on Mercury you would weigh only 38 percent of what you weigh on the Earth. So you don’t need to go on a diet, just go to Mercury. Also a day on Mercury is much longer than a year on Mercury.
Dan: [00:32:31] Oh! Good to know.
Jacinta: [00:32:32] Yeah so a day on the surface of mercury lasts 176 Earth days, but a year takes 88 Earth days, so it’s going around the Sun a lot faster than it’s spinning on its axis.
Dan: [00:32:43] That is interesting.
Jacinta: [00:32:44] Yeah, that’s a little fun fun fact.
Dan: [00:32:47] Okay, I think we’ll wrap it up there. But if you are interested in seeing the transit, Google, follow us at SAAO and at The osmic Savannah and we’ll make sure to keep you updated on where and when you can see it.
Jacinta: [00:32:58] And don’t look at the Sun.
Dan: [00:32:59] And please don’t look at the sun guys, really. It’s not a joke. We really mean it.
Jacinta: [00:33:04] Don’t choose this thing to rebel against. You’ll end up blind.
Dan: [00:33:07] Not this time.
And that’s it for today. Thanks very much for listening. And we hope you’ll join us again on the next episode of The Cosmic Savannah.
Jacinta: [00:33:15] You can visit our website thecosmicsavannah.com where we’ll have links related to today’s episode and you can follow us on Twitter Facebook and Instagram @cosmicsavannah. That’s Savannah spelled S-A-V-A-N-N-A-H.
Dan: [00:33:28] Special thanks today to Dr. Niruj Ramanujam for speaking with us.
Jacinta: [00:33:32] Thanks to Mark Allnut for music production, Janus Brink for the astrophotography, Lana Ceraj for graphic design and Thabisa Fikilepi for social media support.
Dan: [00:33:42] We gratefully acknowledge the support of the South African National Research Foundation and the South African Astronomical Observatory to help keep the podcast running.
Jacinta: [00:33:50] You can subscribe on Apple Podcasts, Spotify or wherever you get your podcasts and if you’d like to help us out, please rate and review us or recommend us to a friend.
Dan: [00:33:59] And we’ll speak to you next time on The Cosmic Savannah.
One Reply to “Episode 16: Transit of Mercury, 11 November 2019”
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