Category: Astrophysics

Are online conferences more inclusive?

Once again, we are entering the summer conference season and, once again, most conferences are taking place in virtual format due to the ongoing travel restrictions and uncertainty due to the Covid-19 pandemic.
Much has in fact already been written about how to make conferences more inclusive, both in person and virtually. So what aspects should be considered as a measure of inclusivity?

Cost

Firstly – cost. The ugly truth is that expensive conference fees, coupled with transport and accommodation costs, often effectively prohibit people from attending meetings due to their location. Travel grants and awards can help to combat this, but are not as much of an equaliser as a fully online format.

Travel

Secondly – even for those who can afford it, travelling long distances is not always possible or desirable. This is especially true for people with family to look after, with teaching obligations, or for people with certain disabilities, for whom the stress is not worth the effort.

Time

Not everyone can afford the luxury of going away for 1-2 weeks. Yet an online format is typically difficult to be fully inclusive in terms of time zones. As an example, next week from 28th June until the 2nd July, the European Astronomical Society (EAS) 2021 meeting takes place; scheduled from 9am to 6pm CEST, which makes sense for a majority European attendance. However, the International Cosmic Ray Conference (ICRC) 2021 from 12th – 23rd July has to cater for a truly international attendance. This is scheduled from 12pm to 7:30pm CEST — which is 7pm to 2:30am in Tokyo and 3am to 10:30 am in Los Angeles. Good luck to colleagues further afield still, in Australia and Hawaii!
In these cases, the online format makes scheduling “live discussions” in which all can participate at a reasonable time, effectively impossible. Such is life when living on a rotating Earth.

Recordings

For the ICRC this year, all contributions (except for plenary talks) have to be recorded and uploaded in advance of the conference. Although it may seem like a pain – one more thing to prepare – in my opinion this is helpful for many people for the following reasons:

1) it enables people to watch talks at a suitable time for them;
2) the talk can be recorded as many times as the presenter likes, thereby getting rid of some nerves;
3) fast speakers can be slowed down and slow speakers can be sped up;
4) parts of a talk can be repeated if necessary (or skipped, e.g. if hearing the same introduction for the Nth time).

The major disadvantage being, of course, that the audience can be much reduced, as fewer people will proactively watch as many talks as they would in person.

Language

English is the de facto language of science in general and international conferences in particular. As a native speaker, I’m fully aware that I have an unfair advantage here. (Also, that my natural writing style is deemed “difficult to read”…)
Online formats can provide non-native speakers of English with more time and flexibility; in preparing their talks; in formulating questions before asking these live or writing and posting online; and in assimilating and understanding information before responding.
Actually, that list applies to everyone, regardless of their native language!

Invisible barriers

There are likely several further, invisible barriers that I have not mentioned so far. These are the less obvious aspects, that you won’t know someone is affected by unless they tell you. For example, at the EAS 2021, a friend is helping to organise this special session on Welfare and Mental Health in Astronomy Research which will no doubt spark valuable discussion; whilst the Cherenkov Telescope Array (CTA) as part of its “Astrodiversity” project has issued a set of guidelines for colour blind friendly publications.

As scientists, it is important to keep learning from each other, and try to make science in general (and astrophysics in particular) a welcoming environment that supports all people involved.
After all, E = mc2 regardless of our differences.

This is how science works

Last time, there was a bit of excitement about the possibility of phosphine in the Venusian atmosphere. This time, I’d like to update the current status of this result and explain how science progresses in practise.

Reproducibility

For any measurement or experimental finding to be considered true and reliable, the results must be reproducible. Independent teams must be able to reach the same conclusion with independent methods or an independent analysis. So upon the news of this exciting finding about phosphine in the Venusian atmosphere and its potential implications for life in our solar system, this is exactly what the scientific community attempted to do – to check and verify the results.

No phosphine? Mis-interpretation?

  1. 15/10/2020 Encrenaz et al. “A stringent upper limit of the PH3 abundance at the cloud top of Venus”
    This team attempted to search for the same spectral feature using data from a different instrument – and did not detect phosphine, instead only placing a limit on the abundance.
  2. 19/10/2020 Snellen et al. “Re-analysis of the 267-GHz ALMA observations of Venus: No statistically significant detection of phosphine”
    This team reanalysed the data used in the original study (from ALMA), and criticised the method used, suggesting that it could create spurious signals that seem to be significant, but are false. They conclude the original results are unreliable.
  3. 28/10/2020 Thompson “The statistical reliability of 267 GHz JCMT observations of Venus: No significant evidence for phosphine absorption“
    This person reanalysed the other dataset used in the original study (from ALMA) and also has the same criticism of the original method used – finding that it can create falsely significant features and that in their reanalysis no indication for phosphine is found.
  4. 27/10/2020 Villanueva et al. “No phosphine in the atmosphere of Venus”
    Possibly the most robust refutal of phosphine detection came from the 26 member strong team claiming no detection of phosphine. The original dataset was, apparently, subject to severe calibration issues. Following their independent calibration and analysis (with different methods), they also did not find any evidence for phosphine. This team also considers that the most significant spectral feature indicating phosphine (PH3) could actually be explained by sulphur dioxide (SO2) — a far less controversial molecule to find in that environment.

Response of the original team

With criticism like that, the original team had to respond and defend their findings. On 16/11/2020, Greaves et al. did just that: “Re-analysis of Phosphine in Venus’ Clouds” in which they re-calibrate and re-analyse the data (removing the aforementioned issues). The detection of phosphine is “tentatively” recovered – at a level 7 times lower than that of their first paper. They also dispute the SO2 interpretation.
(At this point, it is worth noting that at least one independent group supported the detection of phosphine.)

Conclusions:
reliable, reproducible, repeatable.

Scientists don’t always agree, especially when results are new. Findings must be considered reliable enough for others to trust; reproducible by independent groups and methods; and repeatable with different experiments and new data.

So far, it seems the detection of phosphine is neither reproducible, nor reliable – failing two of these tests. Repeatable with new data? Let’s wait and see.
Progress in science is made by trial and error; consensus reached by scientific debate; it’s not always black and white.

Life on Venus?

Last week there was a bit of fuss in the news about whether scientists have found evidence of life on Venus. The short answer is: they haven’t. But they have found something very interesting.

Evidence of a molecule called phosphine (PH3) has been detected in the Venusian atmosphere. This came as such a surprise, that the researchers confirmed it with two different telescopes – the JCMT and ALMA – before publishing their result.
Full article here

Why is Phosphine interesting?

On Earth, the molecule Phosphine is produced primarily by microbial life. Although it can be made by other means, the amount detected is so large (20 parts per billion) that its production is difficult to explain. In their study, the researchers calculated and ruled out the origin of phosphine on Venus from:

— chemical reactions from molecules known to exist in the Venusian atmosphere
— chemical reactions from sub-surface material (i.e. volcanoes etc.)
— UV radiation causing reactions producing phosphine
— lightning causing reactions producing phosphine
— meteorites delivering phosphine to Venus
— large scale comet / asteroid impact delivering phosphine
— solar wind / charged particles interacting in the atmosphere…

None of these explanations could match the data. So the message is:
“We have detected the presence of a molecule in the atmosphere of Venus. We can’t explain by non-microbial means, but on Earth it is produced by microbial life. Can someone explain this?“
Which, with true scientific caution, is not quite the same as “We have found life!”

As Isaac Asimov once famously said:
“The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ but rather ‘That’s funny…’ “

Venus in false colour from the Mariner 10, 1974
Credit

How was the presence of phosphine confirmed?

Slightly technical here, so feel free to skip this part.
All molecules have specific configurations of electrons occupying energy states around their atoms. When these molecules receive energy, such as from photons of light or radiation, the electrons change energy state in discrete transitions. The amount of energy corresponds to a wavelength of electromagnetic radiation. In a spectrum of light from the atmosphere, this wavelength is reduced, causing an “Absorption line” to appear.
Side note: the opposite effect of releasing energy leads to an increase in a particular wavelength, causing “Emission lines”.
Each molecule has a unique combination of possible transitions, creating a fingerprint in the electromagnetic spectrum.

The fingerprint of phosphine in the atmosphere of Venus was detected via an absorption line at 1.123 mm wavelength (i.e. infrared to radio radiation), first with the JCMT (James Clark Maxwell Telescope) and then confirmed with ALMA (the Atacama Large Millimetre / sub-millimetre Array).

The height of phosphine in the atmosphere could be determined from the width of the absorption line. As the planet is rotating, and different layers of atmosphere move at different speeds, an effect similar to the Doppler effect (why sirens change tone when they go past) causes absorption lines to broaden.

What does this mean for alien life?

We’re still looking. Venus, is a hostile place – if you were to dive through the atmosphere and had enough oxygen with you to avoid breathing in sulphuric acid, you’d still be burnt to a crisp before reaching the surface.

Nevertheless, the part of the atmosphere where Phosphine was found is the most hospitable region, with conditions most similar to those found on Earth. If life was found and confirmed on Venus, it would mean that life can survive in far more widespread conditions than previously thought. A large number of exoplanets are currently known – instead of looking for “Earth-like” exoplanets, the door would be thrown wide open for finding life in all kinds of environments.

Ultimately, we are very far from finding another home for ourselves. So in the meantime, we need to take better care of this one planet Earth that we still have.

Stay tuned, let’s see what happens next.

Comets and Conferences

This month we are being visited by comet C/2020 F3, better known as comet NEOWISE, named after the mission that first discovered it. Comets are, roughly speaking, icy rocks from the outer reaches of our solar system. They follow parabolic orbits around the sun; meaning that most of their time is spent at large distances but periodically they come close to the sun. On nearing the sun, they travel much faster (due to the sun’s gravity) and start to warm up, releasing gases. It is this trail of gases that produces the characteristic cometary tail.

Comet NEOWISE reached its closest approach to the sun on the 3rd July and will reach its closest approach to the Earth on the 23rd July. If you miss it, don’t worry, you’ll get another chance in about 6000 years time. So it might be worth trying to see this rare spectacle! Currently, NEOWISE is visible throughout the night with the naked eye and should remain visible until the end of the month. Last night, I even caught a glimpse from the centre of town. (The last time a comet could be seen this easily was perhaps Hale-Bopp in 1997.) Look towards the North West, just below the constellation of Ursa Major (also known as “the plough” or the “big dipper”) and take a few minutes to see if you can spot it. Somehow, I doubt you’ll regret it.

Comet NEOWISE seen from Stanserhorn, Switzerland. Credit: Raphael Niederer, Source: srf.ch

Virtual Conferences

At the start of the month, I attended my first ever virtual conference. In recent years, a move to more online formats has been frequently discussed in the scientific community. Although the motivation to reduce travel in academia has been present for a while, not least for environmental reasons, the move has been accelerated by the current pandemic. The European Astronomical Society annual meeting (EAS 2020) was due to take place in Leiden, Netherlands – but was moved to an online meeting during the same week as originally planned. This actually led to much higher conference attendance – over 1700 participants – and a much reduced conference fee.

Overall, I was fairly impressed. Separate zoom rooms were set up for each session, embedded in the dedicated conference software and hosted by the organisers. There was also a dedicated slack, with separate channels for each session and for different topics. Many features, such as the questions and note taking (exportable to word) worked particularly well. There were a couple of things that – in my opinion – worked even better than an “in real life” conference.

What worked well

  • Attendance: many more people could join online than usual – due to travel costs for those based further away, family commitments or other reasons.
  • Questions: these could be typed and entered at any point during a talk; other people could then upvote questions they wanted to hear answered. At the end of the talk, the most popular questions could then be answered – great idea.
  • Questions 2: run out of time? The conversation continues on the slack channel! Further questions could be asked and answered at leisure and questions were transferred rather than forgotten. Usually, at a conference if you run out of time, forget it. (Unless you’re lucky enough to catch the person in a coffee break later.)
  • Recordings: all of the sessions were recorded, so if there were talks that you had to miss (due to parallel sessions, presenting or other commitments) you could watch them back later.
  • Pre-recordings: some talks – particularly for people in other time zones – could be pre-recorded and played back whilst the presenters themselves were asleep. (Although I did have a colleague who decided to present live anyway – at 2am local time!)
  • Slack: Very useful for getting in touch with people. As well as for conducting quick surveys via emoji reactions! It also meant you could contact people directly (direct messages) without having to search for their email addresses or hunt them down in person. (Let’s face it, we don’t often approach people in person for “minor” points.)
  • Posters: not just a pdf, but gifs, videos and pre-recorded audio presentation – the interactive poster is a different experience!

Nevertheless, it wasn’t perfect – no-one can stay glued to their desk from 9am to 6pm with virtual coffee breaks and parallel lunch sessions too. Several of the above points are also being better addressed by in-person conferences these days, and virtual conferences are no replacement for meeting someone in person.
However, in future we will see a rise in virtual meetings or hybrid events; a new format that the academic world at least is rapidly adjusting to. There are some virtual meetings in my 2021 calendar already.

#BlackLivesMatter – June 10th 2020

Today, 10th June 2020, physicists have called for a Strike for Black Lives. Why? This is not only to add support to the fight against racism and violent discrimination, but also a chance for us to have some uncomfortable conversations. Black people have been and continue to be severely under-represented in academia. We can’t rewrite history, but we can change its course – so why does the percentage of black people in academia remain so low?

Why are there so few black physicists?

Recently I read this article which identified five main influences, that can be roughly categorised as representation (a sense of belonging / self-perception) and support (both academic and personal). In other words, we are discouraged if there are no examples of “people like me”. The absence of coloured physicists is striking, and something I’ve mused upon to colleagues on a few occasions. The ratio is much more biased than in wider society. At several meetings, conferences and work places there is almost always only one black academic. Professionally, I’ve encountered perhaps ~7 people; no more than 10. If you are a black person in academia – you are not alone.

How can we help?

What can we do to improve the situation, without showing favouritism or reducing people to the “token black employee”? Here are a few thoughts.
(Please note – opinions expressed are entirely my own. If I’ve unintentionally offended anyone, or if you have other ideas đŸ™‚ , do not hesitate to let me know)

  • Ensure that we visibly include historical examples of black scientists in outreach and education.
    There is a list of African American scientists on Wikipedia and we would do well to remember and advertise the achievements of Edward Bouchet , George Carruthers , James Harris , Katherine Johnson , Willie Moore , Arthur Walker and others. (and I’m ashamed to learn some of those names for the first time today)
  • Encourage black students and colleagues to join organisations such as https://www.nsbp.org/ not to form “cliques” or promote division, but as a source of support.
  • Advertise opportunities, such as the Bell-Burnell graduate fund that can support people from under-represented backgrounds.
  • Encourage black colleagues to give talks and visibly share their work, collaborate with them and cite them! (Should go without saying.)
  • Give students examples of active black researchers – this could be you too. (Famous examples include Maggie Aderin-Pocock and Neil de Grasse Tyson)

This next one is a bit astronomy specific, but we can give more thought to the cultures we refer to in historical astronomy. We can do more to include not only Asian and Middle-Eastern, but also African, Native American and Aboriginal Australian alongside historical European Astronomy.
(A few minutes on google today led me to the work of Thebe Medupe on traditional African Astronomy and of Duane Hamacher on Aboriginal Australian Astronomy. )

Finally, whilst not being true for all, black people and under-represented groups are facing an uphill battle and may be more reluctant to ask for help – which means we should be all the more willing to offer it.

We are all guilty of unconscious bias; yes, even under-represented groups will also have their own internalised biases. The first step to improvement is becoming more aware of our biases and ways to combat it.

Solar Orbiter

Yesterday, 10th February 2020, saw the successful launch of the Solar Orbiter satellite. This mission will, all being well, provide us with an unprecedented view of our sun, giving us a much better understanding of solar activity, the causes of solar flares and eruptions, as well as in-situ measurements of the solar wind. Let’s break that down a bit.

The sun’s atmosphere, is huge, yet most easily observed from Earth (without extra technology) during a solar eclipse. The uppermost part of the atmosphere is termed the Corona. The solar wind, a stream of charged particles released from the sun, reaches far beyond Earth out through the solar system, yet also has a protective effect against cosmic radiation. For some idea of the scale, the Voyager 2 satellite, launched in 1977, passed Neptune in 1989 yet left the heliosphere in 2018.

Occasionally, the sun releases a significant amount of material (plasma) in a Coronal Mass Ejection (CME). These CME events have the potential to damage and disrupt satellites in orbit around Earth, which could quickly bring down communication and navigation services on which we increasingly rely.

Part of the scientific goals of Solar Orbiter are to better understand these transient events, how and where they form, whether they can be predicted. Solar Orbiter will also give us our first close views of the suns surface near its poles. Just a couple of weeks ago, the most detailed images of the sun’s surface yet were made public, from the Daniel Inouye telescope in Hawaii, resolving for the first time details on the sun’s surface as small as…18 miles.

Despite being continuously seen from Earth, there is a lot we still do not understand about our sun. However, we will have to wait a while for Solar Orbiter to reach it’s final destination, science performance to be verified and the first results made public. Just a few more years should do it.
(see also https://www.mps.mpg.de/solar-physics/solar-orbiter )