Many of you have sent me notes asking what happened to the comments. Comments are permanently off on this blog. I just don't have the time to deal with it. In all honesty, since I have turned them off my daily routine has considerably improved, so they'll remain off. If you've witnessed the misery in my comment sections, you probably saw this coming.

This problem has been caused not so much by commenters themselves, as by Google's miserable commenting platform that doesn't allow blocking or managing problematic people in any way. It adds to this that the threaded comments are terrible to read and that you have to know to click on "LOAD MORE" after 200 comments to even read all replies is a remarkably shitty piece of coding.

I am genuinely sorry about this development because over the years I have come to value the feedback from many of you and I feel like I've lost some friends now. At some point I want to move this blog to a different platform and also write some other stuff again, rather than just posting transcripts. But at the moment I don't have the time.

Having said that, I will from now on cross-post transcripts of my videos at Patreon, where you can interact with me and other Patreons for as little as 2 Euro a month. Hope to see you there.

[This post is written by Ben Alderoty.]

For those who’ve been keeping tabs, my team and I have been working with Sabine since earlier this year to give commenters on her site more ways to talk. Based on your feedback, we’re launching a new way to make that happen: real-time chat rooms. Here’s how they’ll work.

[This post is written by Ben Alderoty from Conversful.]

Conversful launched on BackRe(action) at the end of April. For those that aren’t familiar with our name, Conversful is the app in the bottom corner that allows you to have conversations with other readers. It is still only supported on computers, so if you’re on a phone or tablet right now, come back another time to see what I’m talking about. Based on the feedback we’ve received from many of you, we have been working on some big changes to Conversful and are excited to announce these changes are now live for everyone on BackRe(action).



To participate in Conversful you will now need to create an account. You’ll be able to see a preview of the conversations happening without an account, but to join one or start your own you’ll need to create one. Accounts make it easier to find the right people you want to talk to and maintain those conversations over time.


Conversations on Conversful are still 1-on-1 and start with questions (formerly topics). Questions can pertain to a specific article you might be reading or a more general physics question you are pondering. Ask specific questions as those will elicit the best replies. When you post a question, it will remain open for a week by default and can receive multiple responses. These responses will come in the form of multiple threads within your Conversations tab.

Conversful now works both in real-time and asynchronously. If you see another reader with a green circle next to their name that means they are currently online. We’ll notify you via email if you receive a new message on Conversful when you’re offline. This way you’ll know when to get back on BackRe(action) to continue the conversation. You can control this setting in your profile tab by clicking the avatar in the top left corner of the app.


And that’s it! The app is still pretty simple as we wanted to make it as easy as possible to start conversations and enjoy the one’s you’re already in. We hope that the 1-on-1, private nature of Conversful makes it easy to say something if you’ve ever wanted to, but didn’t want to do so publicly. For all of the active commenters out there, keep commenting! We hope you can use us to continue your conversations and stray into off topic discussions that don’t pertain to a specific post.

As always, please send feedback and suggestions to ben@conversful.com. For those that have given us feedback thus far, thank you so much!

[This post is written by Ben Alderoty from Conversful.]

You may have noticed something new in the bottom corner of BackRe(action) recently. It appears only if you’re on a computer. So if you’re on a phone or tablet right now, finish reading this post, but then come back another time from a computer to see what I’m talking about. That thing is called Conversful & myself with a team of a few others are behind it. I wanted to take a second to give some context as to what Conversful is & how it works.

We built Conversful to create new conversations. We believe that people on the same website at the same time probably have a lot in common. So much so that if they were to meet randomly at a conference, an airport or a bar, they would probably get into a fantastic conversation. But nothing exists right now to make these spontaneous connections happen. With Conversful, we’re trying to create a space where these connections can happen - a “virtual meeting place” of sorts to borrow Sabine’s words.



To open Conversful, just click the globe icon in the bottom corner. With the app open you can do one of two things; start a new conversation or join a conversation. 1️) To start a new conversation, all you’ll need is a topic and your first name. Topics can be anything. So far we’ve seen topics range from “Physics” to “Stephen Wolfram thinks he is close to a unified theory of physics unifying QM and GR. Some opinions?”. Both of these work. There’s no need to overthink a topic, keep it short, and submit it. 2) Joining a conversation is even easier. With the app open, click ‘Join Conversation’ and enter your first name.


Here’s a few other things:

• Conversations on Conversful are 1-1. They are between the person who started the conversation and the person who joined it.
• Conversations on Conversful are real-time. If you post a topic and then leave before someone joins, your topic will disappear. When you come back to the website at a later time you will not have any responses.
• Conversful is for everyone. We designed Conversful to make it feel like you’re texting a friend. Be yourself, share your thoughts, there’s always someone online to hear them out as long as you’re willing to hear theirs.

Today we rolled out a handful of new features to make it easier for conversations to happen. You’re probably seeing some of them right now. If you’ve already tried Conversful and it didn’t end in a conversation, I ask you to please give it another try!

P.S. To make Conversful the best it can be, I would love to hear from you. If you have any thoughts/ideas/feedback on what’s working (or not) and what else you’d like to see, please feel free to email me at (ben@conversful.com). Cheers from NYC & happy conversing!

Moderating comments on this blog is a constant pain. That’s partly because there are always commenters which ignore the comment rules, thus forcing me to step in and reprimand them. Trust me, I don’t enjoy it. But this is a minor hassle. The real trouble with comment sections, here and elsewhere, is that they fulfil two different roles which conflict with each other.

See, my main interest in the comment section is that it contributes to the topic of my blogpost and adds valuable information for other readers. Many commenters, however, would rather use the comment section to discuss their own ideas or have an exchange about something else entirely. Now, in principle I think it’s great if my writing stimulates discussion, but I don’t want it to clog my threads. This brings me in the unfortunate position that I constantly have to tell people to shut up and go elsewhere instead of encouraging them to discuss.

But I may have stumbled over a solution for this problem.

Late last year, I got an email from Ben Alderoty, who had been working on an app that allows website visitors to have private one-on-one conversations. The app is called “Conversful” and if you’re on a laptop or desktop you should see it appear in the bottom right corner of your screen.



Click on the icon, and you are asked to enter a name or pseudonym and a topic you want to have a chat about. I would suggest that you use the same pseudonym that you use for commenting here, so that others recognize you.

Since blogs tend to collect like-minded people, I hope the chances are good that you will find someone to exchange thoughts with, especially since many of you have gotten to know each other over the years already. This blog receives most of its traffic from the USA, Canada, the UK, and Germany. This means that the traffic is the highest between the morning and early afternoon Eastern Time, or between the early afternoon and evening Central European Time, respectively. During these times you are most likely to meet other commenters here.

I want to emphasize that this is a test-run of software which is not yet fully developed and does not have all the functionality you may want from it. But I believe that this idea has much potential. It essentially turns websites in virtual meeting places, where you can have conversations without blasting your words out to the whole world.


If you have feedback or comments on this feature, please let me know, most easily by leaving a comment on this thread. The feedback you provide will go directly to the Conversful team for them to make improvements to the app. If you are running a website yourself where this app might be useful, please get in touch with Ben at ben@conversful.com. For more information about them and their vision, you can also check their website conversful.com.

[Image: Scott McLeod/Flickr]

14 years ago, I was a postdoc in Santa Barbara, in a tiny corner office where the windows wouldn't open, in a building that slightly swayed each time one of the frequent mini-earthquakes shook up California. I had just published my first blogpost. It happened to be about the possibility that the Large Hadron Collider, which was not yet in operation, would produce tiny black holes and inadvertently kill all of us. The topic would soon rise to attention in the media and thereby mark my entry into the world of science communication. I was well prepared: Black holes at the LHC were the topic of my PhD thesis.

1. The LHC “nightmare scenario” has come true (Aug 6, 2016)


2. The multiworse is coming (Mar 13, 2018)


3. Outraged about the Google diversity memo? I want you to think about it. (Aug 9, 2017)


4. No, physicists have not created “negative mass” (Apr 21, 2017)


5. A Philosopher Tries to Understand the Black Hole Information Problem (May 11, 2017)


6. The present phase of stagnation in the foundations of physics is not normal (Nov 19, 2018)


7. The crisis in physics is not only about physics (Oct 30, 2019)


8. The Forgotten Solution: Superdeterminism (Jul 28, 2019)


9. String theory pros and cons [video - no singing!] (Oct 22, 2018)


10. Dark matter nightmare: What if we are just using the wrong equations? (Oct 16, 2019)

I wish you all a good start into the New Year!

Chad Orzel is a physics prof whose research is primarily in atomic physics. He also blogs next door and is a good-humored and eminently reasonably guy, so I hope he will forgive me if I pick on him a little.

Two weeks ago I complained about the large number of dark matter experiments that hunt for hypothetical particles, particles invented just because you can hunt for them. Chad’s response to this is “Physicists Gotta Physics” and “I don't know what else Hossenfelder expects the physicists involved to do.”

To which I wish to answer: If you don’t know anything sensible to do with your research funds, why should we pay you? Less flippantly:

Dear Chad,

I find it remarkable how many researchers think they are entitled to tax-money. I am saddened to see you are one of them. Really, as a science communicator you should know better. “We have to do something, so let us do anything” does not convince me, and I doubt it will convince anyone else. Try harder.

But I admit it is unfair to pick on Chad in particular, because his reaction to my blogpost showcases a problem I encounter with experimentalists all the time. They seem to not understand just how badly motivated the theories are that they use to justify their work.

By and large, experimentalists like to think that looking for those particles is business as usual, similar to how we looked for neutrinos half a century ago, or how we looked for the heavier quarks in the 1990s.

But this isn’t so. These new inventions are of considerably lower quality. We had theoretically sound reasons to think that neutrinos and heavy quarks exist, but there are no similarly sound reasons to think that these new dark matter particles should exist.

Philosophers would call the models strongly underdetermined. I would call them wishful thinking. They’re little more than guesses. Making these experiments, therefore, is playing roulette on an infinitely large table: You will lose with probability 1. It is almost certain to waste time and money. And the big tragedy is that with some thinking, we could invest resources much better.

Orzel complains that I am exaggerating how specific these searches are, but let us look at some of those.

Like this one about using the Aharonov-Bohm effect. It proposes to search for a hypothetical particle called the dark photon which may mix with the actual photon and may form a condensate which may have excitations that may form magnetic dipoles which you may then detect. Or, more likely, just doesn’t exist.

Or let us look at this other paper, which tests for space-time varying massive scalar fields that are non-universally coupled to standard model particles. Or, more likely, don’t exist.

Some want to look for medium mass weakly coupled particles that scatter off electrons. But we have no reason to think that dark matter particles are of that mass, couple with that strength, or couple to electrons to begin with.

Some want to look for something called the invisible axion, which is a very light particle that couples to photons. But we have no reason to think that dark matter couples to photons.

Some want to look for domain walls, or weird types of nuclear matter, or whole “hidden sectors”, and again we have no reason to think these exist.

Fact is, we presently have no reason to think that dark matter particles affect normal matter in any other way than by the gravitational force. Indeed, we don’t even have reason to think it is a particle.

Now, as I previously said I don’t mind if experimentalists want to play with their gadgets (at least not unless their toys cost billions, don’t get me started). What I disapprove of is if experimentalists use theoretical fantasies to motivate their research. Why? Think about it for a moment before reading on.

Done thinking? The problem is that it creates a feedback cycle.

It works like this: Theorists get funding because they write about hypothetical particles that experiments can look for. Experimentalists get funding to search for the hypothetical particles, which encourages more theorists to write papers about those particles, which makes the particles appear more interesting, which gives rise to more experiments. Rinse and repeat.

The result is lot of papers. It looks really productive, but there is no reason to think this cycle will converge on a theory that is an actually correct description of nature. More likely, it will converge on a theory that can be eternally amended so that one needs ever better experiments to find the particles. Which is basically what has been going on the past 40 years.

So, Orzel asks perplexed, does Hossenfelder actually expect scientists to think before they spend money? I actually do.

The foundations of physics have seen 40 years of stagnation. Why? It is clearly neither a lack of theories nor a lack of experiments, because we have seen plenty of both. Before asking for money to continue this madness, everyone in the field should think about what is going wrong and what to do about it.

My book “Lost in Math: How Beauty Leads Physics Astray” was recently translated to French. Today is your chance to win a free copy of the French translation! The first three people who submit a comment to this blogpost with a brief explanation of why they are interested in reading the book will be the lucky winners.

The only entry requirement is that you must be willing to send me a mailing address. Comments submitted by email or left on other platforms do not count because I cannot compare time-stamps.

Update: The books are gone.

I keep getting notifications from readers that something isn't working on my blog. Here is what's happening: With the new layout of the comment section, if the list exceeds 100 comments, then comments will by default not all load. In that case you have to click on "Load more..." below the comment box, see screen shot below. I have posted this response several times in the comments, but of course you'll only see this if you already know you have to click on "Load more..."



I also know that if you click on the link in the comment widget (side bar), this will not work if there are too many comments in one thread. I am sorry about this, but nothing I can do to change it. This blog is hosted by Google. My options to customize the comment section are very limited. The comment widget is a 3rd party java script that however can't handle the more recent updates of the comment feature.

I have also noticed that sometimes the comment box doesn't appear in a reply-to-comment thread. In that case you have to scroll up to the comment you want to reply to and find the "reply" link. If you click on that, the box will appear. I have no idea what sense this makes. If anyone has suggestions for improvement other than that I should move this blog to a different provider, please let me know.

And while I am at it, let me repeat my plea that you please, please not post links or email addresses. First, because such comments are likely to end up in the spam folder. Even if not, I will only approve such comments after I have had time to check that the website is legit. Since I normally don't have time to do that, your comment will end up in the moderation queue indefinitely. Exceptions are links to websites I can recognize immediately, eg the arXiv, scientific journals, major news pages, etc.

We wish you all happy holidays! Whether or not you celebrate Christmas, we hope you have a peaceful time to relax and, if necessary, recover.

I want to use the opportunity to thank all of you for reading along, for giving me feedback, and for simply being interested in science in a time when that doesn’t seem to be normal anymore. A special “Thank you" to those who have sent donations. It is reassuring to know that you value this blog. It encourages me to keep my writing available here for free.

I’ll be tied up with family business during the coming week – besides the usual holiday festivities, the twins’ 7th birthday is coming up – so blogging will be sparse for some while.

I’ll be traveling the next two weeks. First to Cambridge to celebrate Stephen Hawking’s 75th birthday (which was in January), then in Trieste for a conference on “Probing the spacetime fabric: from concepts to phenomenology.”  Rant coming up later today, but after that please prepare for a slow time.

I have a trip upcoming to Helsinki. After this I'll be tied up in family business, and then my husband goes on a business trip and I have the kids alone. Then Kindergarten will be closed for a day (forgot why, I'm sure they must have some reason), I have to deal with an ant-infection in our apartment, and more family business follows. In summary: busy times.

I have a book review to appear on this blog later today, but after this you won't hear much from me for a week or two. Keep in mind that since I have comment moderation on, it might take some while for your comment to appear when I am traveling. With thanks for your understanding, here's a random cute pic of Gloria :)

Heavy paper.

What would you say if a man with British accent cold-calls you one evening to offer money because he likes your blog?

I said no.

In my world – the world of academic paper-war – we don’t just get money for our work. What we get is permission to administrate somebody else’s money according to the attached 80-page guidelines (note the change in section 15b that affects taxation of 10 year deductibles). Restrictions on the use of funds are abundant and invite applicants to rest their foreheads on cold surfaces.

The German Research Foundation for example, will – if you are very lucky – grant you money for a scientific meeting. But you’re not allowed to buy food with it. Because, you must know, real scientists don’t eat. And to thank you for organizing the meeting you don’t yourself get paid – that wouldn’t be an allowed use of funds. No, they thank you by requesting further reports and forms.

At least you can sometimes get money for scientific meetings. But convincing a funding agency to pay a bill for public outreach or open access initiatives is like getting a toddler to eat broccoli: No matter how convincingly you argue it’s in their own interest, you end up eating it yourself. And since writing proposals sucks, I mean, sucks up time, at some point I gave up trying to make a case that this blog is unpaid public outreach that you'd think research foundations should be supportive of. I just write – and on occasion I carefully rest my forehead on cold surfaces.

Then came the time I was running low on income – unemployed between two temporary contracts – and decided to pitch a story to a magazine. I was lucky and landed an assignment instantly. And so, for the first time in my life, I turned in work to a deadline, wrote an invoice, and got paid in return. I. Made. Money. Writing. It was a revelation. Unfortunately, my published masterwork is now hidden behind a paywall. I am not happy about this, you are not happy about this, and the man with the British accent wasn’t happy about it either. Thus his offer.

But I said no.

Because all I could see was time wasted trying to justify proper means of spending someone else’s money on suitable purposes that might be, for example, a conference fee that finances the first class ticket of the attending Nobel Prize winner. That, you see, is an allowed way of spending money in academia.

My cold-caller was undeterred and called again a week later to inquire whether I had changed my mind. I was visiting my mom, and mom, always the voice of reason, told me to just take the damn money. But I didn’t.

I don’t like being reminded of money. Money is evil. Money corrupts. I only pay with sanitized plastic. I swipe a card through a machine and get handed groceries in return – that’s not money, that’s magic. I look at my bank account statements so rarely I didn’t notice for three years I accidentally paid a gym membership fee in a country I don’t even live. In case my finances turn belly-up I assume the bank will call and yell at me. Which, now that I think of it, seems unlikely because I moved at least a dozen times since opening my account. And I’m not good updating addresses either. I did call the gym though and yelled at them – I got my money back.

Then the British man told me he also supports Tim Gowers new journal. “G-O-W-ers?,” I asked. Yes, that Tim. That would be the math guy responsible for the equations in my G+ feed.

Tim Gowers. [Not sure whose photo, but not mine]

Tim Gowers, of course, also writes a blog. Besides that, he’s won the 1998 Fields Medal which makes him officially a genius. I sent him an email inquiring about our common friend. Tim wrote back he reads my blog. He reads my blog! A genius reads my blog! I mean, another genius – besides my mom who gets toddlers to eat broccoli.

Thusly, I thought, if it’s good enough for Gowers, it’s probably good enough for me. So I said yes. And, after some more weeks of consideration, sent my bank account details to the British man. You have to be careful with that kind of thing, says my mom.

That was last year in December. Then I forgot about the whole story and returned to my differential equations.

Tim, meanwhile, got busy setting up the webpage for his new journal “Discrete Analysis” which covers the emerging fields related to additive combinatorics (not to be confused with addictive combinatorics, more commonly known as Sudoku). His open-access initiative has attracted some attention because the journal’s site doesn’t itself host the articles it publishes – it merely links to files which are stored on the arXiv. The arXiv is an open-access server in operation since the early 1990s. It allows researchers in physics, math, and related disciplines to upload and share articles that have not, or not yet, been peer-reviewed and published. “Discrete Analysis” adds the peer-review, with minimal effort and minimal expenses.

Tim’s isn’t the first such “arxiv-overlay” journal – I myself published last year in another overlay-journal called SIGMA – but it is still a new development that is eyed with some skepticism. By relying on the arXiv to store files, the overlays render server costs somebody else’s problem. That’s convenient but doesn’t make the problem go away. Another issue is that the arXiv itself already moderates submissions, a process that the overlay journals have no control over.

Either way, it is a trend that I welcome because overlays offer scientists what they need from journals without the strings and costs attached by commercial publishers. It is, most importantly, an opportunity for the community to reclaim the conditions under which their research is shared, and also to innovate the format as they please:

“I wanted it to be better than a normal journal in important respects,” says Tim, “If you visit the website, you will notice that each article gives you an option to click on the words ‘Editorial introduction.’ If you do so, then up comes a description of the article (not on a new webpage, I hasten to add), which sets it in some kind of context and helps you to judge whether you want to find out more by going to the arXiv and reading it.”

But even overlay journals don’t operate at zero cost. The website of “Discrete Analysis” was designed by Scholastica’s team, and their platform will also handle the journal’s publication process. They charge $10 per submission and there are a couple of other expenses that the editorial board has to cover, such as services necessary to issue article DOIs. Tim wants to avoid handing on the journal expenses to the authors. Which brings in, among others, the support from my caller with the British accent.

In the two months that passed since I last heard from him, I found out that 10 years ago someone proved there is no non-trivial solution to the equations I was trying to solve. Well, at least that explains why I couldn’t find one. My hence scheduled two-day cursing retreat was interrupted by a message from The British Man. Did the money arrive?, he wanted to know. This way forced to check my bank account, it turned out not only didn’t his money arrive, but neither did I ever receive salary for my new job.

This gives me an excuse to lecture you on another pitfall of academic funding. Even after you have filed five copies of various tax-documents and sent the birth dates of the University President and Vice-president to an institution that handles your grant for another institution and is supposed to wire it to a third institution which handles it for your institution, the money might get lost along the way – and frequently does.

In this case they simply forgot to put me on the payroll. Luckily, the issue could be resolved quickly, and the next day also the wire transfer from Great Britain arrived. Good thing because, as mommy guilt reminded me, this bank account pays for the girls’ daycare and lunch. My writer friends won’t be surprised to hear however that I also had to notice several payments for my freelance work did not come through. When I grow up, I hope someone tells me how life works. /lecture

Tim Gowers invited submissions for “Discrete Analysis” starting last September, and the website of the new journal launched today; you can read his own blogpost here. For the community, they key question is now whether arxiv-overlay journals like Tim’s will be able to gain a status similar to that of traditional journals. The only way to find out is to try.

Public outreach in general, and science blogging in particular, is vital for the communication of science, both within our communities and to the public. And so are open access initiatives. Even though they are essential to advance research and integrate it into our society, funding agencies have been slow to accept these services as part of their mission.

While we wait for academia to finally digest the invention of the world wide web, it is encouraging to see that some think forward. And so, I am happy today to acknowledge this blog is now supported by the caller with the British accent, Ilyas Khan of Cambridge Quantum Computing. Ilyas has quietly supported a number of scientific endeavors. Although he is best known for enabling Wittgenstein's Nachlass to become openly and freely accessible by funding the project that was implemented by Trinity College Cambridge, he is also a sponsor of Tim Gowers' new journal Discrete Analysis.

Yes, today marks the 10th anniversary of my first post on this blog.

I started blogging while I was in Santa Barbara, in a tiny fifth-floor office that slightly swayed with the occasional Earthquakes. I meant to write about postdoc-life in California, but ended up instead writing mostly about my research interests. Because, well, that's what I'm interested in. Sorry, California.

Those were the years of the String Wars and of Black Holes at the LHC. And since my writing was on target, traffic to this blog increased rapidly -- a somewhat surprising and occasionally disturbing experience.

Over the years, I repeatedly tried to share the work of regularly feeding this blog, but noticed it's more effort trying to convince others to write than to just write myself. And no, it's not zero effort. In an attempt to improve my Germenglish, I have read Strunk's "Elements of Style" forwards and backwards, along with several books titled "Writing Well" (which were written really well!), and I hope you benefit from it. For me, the outcome has been that now I can't read my older blogposts without crying over my own clumsy writing. Also, there's link-rot. But if you have some tolerance for awkward English and missing images, there's 10 years worth of archives totalling more than 1500 entries waiting in the side-bar.

The content of this blog has slightly changed over the years. Notably, I don't share links here any more. For this, I use instead my twitter and facebook accounts, which you can follow to get reading recommendations and the briefer commentaries. But since I can't stand cluttered pages, this blog is still ad-free and I don't make money with it. So if you like my writing, please have a close look at the donate-button in the top-right corner.

In the 10 years that have passed, this blog moved with me through the time-zones, from California to Canada, from Canada to Sweden, and from Sweden eventually back to Germany. It witnessed my wedding and my pregnancy and my daughters turning from babies to toddlers to Kindergartners. And the journey goes on. As some of you know already, I'm writing a book (or at least I'm supposed to be writing a book), so stay tuned, there's more to come.

I want to thank all of you for reading along, especially the commenters. I know that some of you have been around since the first days, and you have become part of my extended family. You have taught me a lot, about life and about science and about English grammar.

A special thank you goes to those of you who have sent me donations since I put up the button a few months ago. It is a great encouragement for me to continue.

I'm back from my trip. Here are some things that prevented me from more substantial blogging:

• I wrote an article for Aeon, "The superfluid Universe," which just appeared. For a somewhat more technical summary, see this earlier blogpost.
• I did a Q&A with John The-End-of-Science Horgan, which was fun. I disagree with him on many things, but I admire his writing. He is infallibly skeptic and unashamedly opinionated -- qualities I find lacking in much of today's science writing, including, sometimes, my own.
• I spoke with Davide Castelvecchi about Stephen Hawking's recent attempt to solve the black hole information loss problem, which I previously wrote about here.
• And I had some words to spare for Zeeya Merali, probably more words than she wanted, on the issue with the arXiv moderation, which we discussed here.
• Finally, I had the opportunity to give some input for this video on the PhysicsGirl's YouTube channel:
  
  
  
  I previously explained in this blogpost that Hawking radiation is not produced at the black hole horizon, a correction to the commonly used popular science explanation that caught much more attention than I anticipated.
  
  There are of course still some things in the above video I'd like to complain about. To begin with, anti-particles don't normally have negative energy (no they don't). And the vacuum is the same for two observers who are moving relative to each other with constant velocity - it's the acceleration that makes the difference between the vacua. In any case, I applaud the Physics Girl team for taking on what is admittedly a rather technical and difficult topic. If anyone can come up with a better illustration for Hawking-radiation than Hawking's own idea with the pairs that are being ripped apart (which is far too localized to fit well with the math), please leave a suggestion in the comments.

Over the years the discussion of my blogposts has shifted over to facebook. To follow this trend and to make it easier for you to engage, I have now set up a facebook page for this blog. Just "like" the page to get the newest blogposts and other links that I post :)

Last year I got a strange email, from a person entirely unknown to me, letting me know that one of their acquaintances seemed to pretend an ultrasound image from my twin pregnancy was their own. They sent along the following screen capture that shows a collection of ultrasound images. It springs to the eye that these images were not taken with the same device as they differ in contrast and color scheme. It seems exceedingly unlikely you would get this selection of ultrasound image from one screening.

In comparison, here is my ultrasound image at 14 weeks pregnancy, taken in July 2010:



You can immediately see that the top right image from the stranger is my ultrasound image, easily recognizable by the structure in the middle that looks like an upside-down V. The header containing my name is cropped. I don’t know where the other images came from, but I’d put my bets on Google.

I didn’t really know what to make of this. Why would some strange woman pretend my ultrasound images are theirs? Did she fake being pregnant? Was she indeed pregnant but didn’t have ultrasound images? Did she just not like their own images?

My ultrasound images were tiny, glossy printouts, and to get them online I first had to take a high resolution photo of the image, straighten it, remove reflections, turn up contrast and twiddle some other software knobs. I’m not exactly an award-winning photoshopper, but from the images that Google brings up, mine is one with the highest resolution.

So maybe somebody just wanted to save time, thinking ultrasound images all look alike anyway. Well, they don’t. Truth be said, to me reading an ultrasound is somewhat like reading tea leaves, and I’m a coffee drinker. But the days in which ultrasound images all looked alike are long gone. If you do an inverse image search, it identifies my ultrasound flawlessly. And then there’s the upside-down V that my doctor said was the cord, which might or might not be correct.

The babies are not a boy and a girl, as is claimed in the caption of the screenshot; they are two girls with separate placentas. In the case with two placentas the twins might be fraternal – stemming from two different eggs – or identical – stemming from the same egg that divided early on. We didn’t know they were two girls though until 20 weeks, at which age you should be able to see the dangling part of the genitals, if there is one.

If I upload an image to my blog, I do not mind it being used by other people. What irked me wasn’t somebody used my image, but that they implicitly claimed my experience was theirs.

In any case, I forgot all about this bizarre story until last week I got another note from a person I don’t know, alerting me that somebody else is going about pretending to carry my children. Excuse me if I might not have made too much effort in blurring out the picture of the supposedly pregnant woman


This case is even more bizarre as I’ve been told the woman apparently had her uterus removed and is claiming the embryos have attached to other organs. Now, it is indeed possible that a fertilized egg implants outside the uterus and the embryo continues to grow, sometimes for several months. The abdomen for example has a good blood circulation that can support a pregnancy for quite some while. Sooner or later though the supply of nutrients and oxygen will become insufficient, and the embryo dies, triggering a miscarriage. That’s a major problem because if the pregnancy isn’t in the uterus the embryo has no exit through which to leave. Such out-of-place pregnancies are medical emergencies and, if not discovered early on, normally end fatally for the mother: Even if the dead embryo can be surgically removed, the placenta has grown into the abdomen and cannot detach the way it can cleanly separate from the rather special lining of the uterus, resulting in heavy inner bleeding and, often, death.

Be that as it may, if you’ve had your uterus removed you can’t get pregnant because the semen has no way to fertilize an egg.

I do not have the faintest clue why somebody would want to fake a twin pregnancy. But then the internet seems to proliferate what I want to call, in absence of a better word, “experience theft”. Some people pretend to suffer from an illness they don’t have, travel to places they’ve never been, or having grown up as members of a minority when they didn’t. Maybe pretending to be pregnant with twins is just the newest trend.

Well, ladies, so let me tell you what to expect, so you will get it right. At 20 weeks you’ll start getting preterm contractions, several hours a day, repeating stoically every 10 minutes. They’ll turn out to be what is called “not labor active”, pushing inwards but not downwards, still damned painful. Doctors warn that you’ll have a preterm delivery and issue a red flag: No sex, no travel, no exercise for the rest of the pregnancy.

At 6 months your bump will have reached the size of a full-term single pregnancy, but you still have 3 months to go. People start making cheerful remarks that you must be almost due! Your cervix length has started to shorten and it is highly recommended you stay in bed with your hips elevated and so you’ll go on sick leave following the doctor’s advice. The allegedly so awesome Swedish health insurance will later refuse to cover for this and you’ll lose two months worth of salary.

By 7 month your cervix length has shortened to 1 cm and the doctors get increasingly nervous. By 8 months it’s dilated 1 cm. You’re now supposed to visit your doctor every day. Every day they record your contractions, which still come, “not labor active”, in 10 minute intervals. They still do when you’ve reached full term, at which point you’ll start developing a nasty kidney problem accompanied by substantial water retention. And so, after warning you of a preterm delivery for 4 months, the doctors now insist that you have labor induced.

Once in the hospital they put you on Cytotec, which after 36 hours hasn’t had any effect other than making you even more miserable. But since the doctors expect that you will need a Cesarean section eventually, they don’t want you to eat. After 48 hours mostly lying in bed, not being allowed to eat more than cookies – while being 9 month pregnant with twins! –  your blood pressure will give in and one of the babies’ heartbeats will drop from a steady 140 to 90. And then it’s entirely gone. An electronic device starts beeping widely, a nurse pushes a red button, and suddenly you will find yourself with an oxygen mask on your face and an Epinephrine shot in your vein. You use the situation to yell at a doctor to stop the Cytotec nonsense and put you on Pitocin, which they promise to do the next morning.

The next morning you finally get your PDA and the Pitocin does its work. Within an hour you’ll go from 1 cm to 8 cm dilation. Your waters will never break – a midwife will break them for you. Both. The doctor insists on shaving off your hair “down there”, because he still expects you’ll need a Cesarean. These days, you don’t deliver twins naturally any more, is the message you get. Eventually, after eternity has come and gone, somebody will ask you to push. And push you will, 5 times for two babies.

I have no scars and I have no stretch marks. The doctor never got to use his knife. I’m living proof you don’t need a Cesarean to give birth to twins. The children whose ultrasound image you’ve used are called Lara Lily and Gloria Sophie. At birth, they had a low weight, but full Apgar score. They are now 4 years old, beat me at memory, and their favorite food is meatballs.

The twins are now 4 years old.

If there are two cases that have been brought to my attention that involve my images, how many of these cases are there in total?

Update: Read comments for some more information about the first case.

“I am a phd-student in neuroscience and I often get the impression that in physics "everything is better". E.g. they replicate their stuff, they care about precision, etc. I've always wondered to what extend that is actually true, as I obviously don't know much about physics (as a science). I've also heard (but to a far lesser extent than physics being praised) that in theoretical physics you can make up anything bc there is no way of testing it. Is that true? Sorry if that sounds ignorant, as I said, I don't know much about it.”

This question was put forward to me by Amoral Atheist at Neuroskeptic’s blog.

Dear Amoral Atheist:

I appreciate your interest because it gives me an opportunity to lay out the relation of physics to other fields of science.

About the first part of your question. The uncertainty in data is very much tied to the objects of study. Physics is such a precise science because it deals with objects whose properties are pretty much the same regardless of where or when you test them. The more you take apart stuff, the simpler it gets, because to our best present knowledge we are made of only a handful of elementary particles, and these few particles are all alike – the electrons in my body behave exactly the same way as the electrons in your body.

If the objects of study get larger, there are more ways the particles can be combined and therefore more variation in the objects. As you go from elementary particle physics to nuclear and atomic physics to condensed matter physics, then chemistry and biology and neuroscience, the variety in construction become increasingly important. It is more difficult to reproduce a crystal than it is to reproduce a Hydrogen atom, and it is even more difficult to reproduce cell cultures or tissue. As variety increases, expectations for precision and reproducibility go down. This is the case already in physics: Condensed matter physics isn’t as precise as elementary particle physics.

Once you move past a certain size, where the messy regime of human society lies, things become easier again. Planets, stars, or galaxies as a whole, can be described with high precision too because for them the details (of, say, organisms populating the planets) don’t matter much.

And so the standards for precision and reproducibility in physics are much higher than in any other science not because physicists are smarter or more ambitious, but because the standards can be higher. Lower standards for statistical significance in other fields is nothing that researchers should be blamed for, it comes with their data.

It is also the case though that since physicists have been dealing with statistics and experimental uncertainty at such high precision since hundreds of years, they sometimes roll eyes about erroneous handling of data in other sciences. It is for example a really bad idea to only choose a way to analyze data after you have seen the results, and you should never try several methods until you find a result that crosses whatever level of significance is standard in your field. In that respect I suppose it is true that in physics “everything is better” because the training in statistical methodology is more rigorous. In other words, one is lead to suspect that the trouble with reproducibility in other fields of science is partly due to preventable problems.

About the second part of your question. The relation between theoretical physics and experimental physics goes both ways. Sometimes experimentalists have data that needs a theory by which they can be explained. And sometimes theorists have come up with a theory that they need new experimental tests for. This way, theory and experiment evolves hand in hand. Physics, as any other science, is all about describing nature. If you make up a theory that cannot be tested, you’re just not doing very interesting research, and you’re not likely to get a grant or find a job.

Theoretical physicists, as they “make up theories” are not free to just do whatever they like. The standards in physics are high, both in experiment and in theory, because there are so many data that are known so precisely. New theories have to be consistent with all the high precision data that we have accumulated in hundreds of years, and theories in physics must be cast in the form of mathematics; this is an unwritten rule, but one that is rigorously enforced. If you come up with an idea and are not able to formulate it in mathematical terms, nobody will take you seriously and you will not get published. This is for good reasons: Mathematics has proved to be an enormously powerful way to ensure logical coherence and prevent humans from fooling themselves by wishful thinking. A theory lacking a mathematical framework is today considered very low standard in physics.

The requirement that new theories both be in agreement with all existing data and be mathematically consistent – ie do not lead to internal disagreements or ambiguities – are not easy requirements to fulfil. Just how hard it is to come up with a theory that improves on the existing ones and meets these requirements is almost always underestimated by people outside the field.

There is for example very little that you can change about Einstein’s theory of General Relativity without ruining it altogether. Almost everything that you can imagine doing to its mathematical framework has dire consequences that lead to either mathematical nonsense or to crude conflict with data. Something as seemingly innocuous as giving a tiny mass to the normally massless carrier field of gravity can entirely spoil the theory.

Of course there are certain tricks you can learn that help you invent new theories that are not in conflict with data and are internally consistent. If you want to invent a new particle for example, as a rule of thumb you better make it very heavy or make it very weakly interacting, or both. And make sure you respect all known symmetries and conservation laws. You also better start with a theory that is known to work already and just twiddle it a little bit. In other words, you have to learn the rules before you break them. Still, it is hard and new theories don’t come easily.

Dark matter is a case in point. Dark matter has first been spotted in the 1930s. 80 years later, after the work of tens of thousands of physicists, we have but a dozen possible explanations for what it may be that are now subject to further experimental test. If it was true that in theoretical physics you “can make up anything” we’d have hundreds of thousands of theories for dark matter! It turns out though most ideas don’t meet the standards and so they are discarded of very quickly.

Sometimes it is very difficult to test a new theory in physics, and it can take a lot of time to find out how to do it. Pauli for example invented a particle, now called the “neutrino,” to explain some experiments that physicists were confused about in the 1930s, but it took almost three decades to actually find a way to measure this particle. Again this is a consequence of just how much physicists know already. The more we know, the more difficult it becomes to find unexplored tests for new ideas.

It is certainly true that some theories that have been proposed by physicists are so hard to test they are almost untestable, like for example parallel universes. These are extreme outliers though and, as I have complained earlier, that they are featured so prominently in the press is extremely misleading. There are few physicists working on this and the topic is very controversial. The vast majority of physicists work in down-to-earth fields like plasma physics or astroparticle physics, and have no business with the multiverse or parallel universes (see my earlier post “What do most physicists work on?”). These are thought-stimulating topics, and I find it interesting to discuss them, but one shouldn’t mistake them for being central to physics.

Another confusion that often comes up is the relevance of physics to other fields of science, and the discussion at Neurosceptic’s blogpost is a sad example. It is perfectly okay for physicists to ignore biology in their experiments, but it is not okay for biologists to ignore physics. This isn’t so because physicists are arrogant, it is because physics studies objects in their simplest form when their more complicated behavior doesn’t play a role. But the opposite is not the case: The simple laws of physics don’t just go way when you get to more complicated objects, they still remain important.

For this reason you cannot just go and proclaim that human brains somehow exchange signals and store memory in some “cloud” because there is no mechanism, no interaction, by which this could happen that we wouldn’t already have seen. No, I'm not narrowminded, I just know how hard it is to find an unexplored niche in the known laws of nature to hide some entirely new effect that has never been observed. Just try yourself to formulate a theory that realizes this idea, a theory which is both mathematically consistent and consistent with all known observations, and you will quickly see that it can’t be done. It is only when you discard the high standard requirements of physics that you really can “make up anything.”

Thanks for an interesting question!

I recently gave a seminar on the use of social media for scientists at an internal event at Stockholm University. It was an opportunity to collect my thoughts, and also to summarize what shortcomings the presently available platforms have. It would be odd if I didn’t share this with you, wouldn’t it?

There are many uses of social media, but three of them are particularly important for science: Networking, Communication, and Outreach.

Networking can best be described as the making and maintain of contacts and the exchange of information. It blends into science communication, which is more generally about discussing your own or others’ research, with your community or with the public. And then there is public outreach, which has a broader aim because you may also want to draw attention to your institution or yourself, or to generally get people engaged in science.


Networking is really unavoidable if you want to work in science today – and you are almost certainly doing it already. Communication is essential for research, and so I think using social media to this end is part of being a good scientist. And I strongly encourage you to try if you like public outreach because of its many benefits. I don’t think every scientist must engage in public outreach; in the first line scientists should do science. But it can be very rewarding and helpful to your science too, so if you have both the time and the interest, you should definitely consider it.

A lot of scientists I know shy away from using social media for no good reason and seem to believe twitter and facebook are somehow not intellectual enough. Or maybe they mistrust their own abilities to withstand the temptation of cat videos. To me twitter, facebook, blogger and, to a lesser extent, Google plus and ResearchGate are simply tools that help me to stay up to date, keep in touch with colleagues, discuss science, get feedback and advice, and share my own research.

There are many other reasons to use social media, but they are all driven by the underlying changes in the communities: We are more people in science today than ever before, collaborations are becoming more international, there are more and more papers being published. Social media is a good way to manage this. If you’re not using social media, you are putting yourself at a disadvantage, it’s as simple as that.

I have the slides of my talk online here, where I have some remarks on the social media platforms presently most widely used by scientists: Twitter, Facebook, ResearchGate, LinkedIn and Google+. In physics in particular there are also the PhysicsForums and the Physics Stack Exchage which are well frequented and can be really useful to ask questions, and give or get answers. These services differ somewhat in their aim and use, so if you are new to this you might want to check these out and see what suits you best.

The existing platforms leave me wanting for the following reasons:

• None of the existing social media sites covers the spectrum from professional to personal contacts.
  
  Presently we either have pages like LinkedIn and ResearchGate that focus entirely on job experience and skills and, in the case of ReseachGate, publications. Or we have sites like Facebook and Google+ where you don’t have this at all. But I know most of my colleagues personally, and I am also interested to hear what is going on in their life beyond the publication record or changes of affiliation. For me, like for many scientists I know, work life and private life blur together. Maybe it’s the shared experience of losing friends during the postdoc time that creates these ties, be that as it may, it’s a reality of research.
  
  I mostly use facebook, because there we also talk about the human side of science, the frustration with peer review, the nuisance of writing proposals, the inevitable rejections, the difficulties of balancing work with family, travel stress, conference experiences, and so on. To me this is part of life as a scientist. Every one of us goes through difficult times every one and then, and using social media is a way to both get and give support. So even if I were using a site like ResearchGate, I would still use other sites in addition to this.
• None of the existing sites integrates a useful archiving function.
  
  This is something I really don’t understand: Why isn’t there a way to tag posts on either of these platforms with keywords or move them into folders for your own reference? On facebook you can now at least do a keyword search on your timeline, but it is working badly. On twitter too you can search your posts, though you have to use a third party service for that. Still, I and others I talked to, often get frustrated not being able to find a particular post or reference or comment.
  
  There are of course apps like for example Evernote that allow you to basically archive anything you want in categories of choice with keywords, and to a lesser extent you can do this on Feedly too. But then if you archive a reference, you will not have the discussion about it in the same place.
• The professional sites are too public.
  
  Michael Nielsen in his book “Reinventing Discovery” has a charming analogy in which he describes a scientist with an unfinished idea as someone owning only one shoe, looking for a match without wanting to show the shoe to anybody. Nielsen describes how awkward and hesitant scientists can be before they start talking about their lonely shoes, and I find much truth in this analogy. It’s all well and fine if you have a question and ask it at the Stack Exchange or ResearchGate or facebook or wherever. But that really isn’t how it works if you are looking for a collaborator.
  
  To begin with you might not know exactly what the question is, or what you are looking for isn’t somebody explaining how to do a calculation but somebody interested enough to actually do it in exchange for being coauthor. There is also the prevalent academic paranoia of getting scooped. Especially in fields where competition is high, people don’t normally go around and publicly distribute their half-done research projects. And then, maybe most importantly, both the person asking and the person answering might have some misunderstandings and they might be afraid of their mistakes being publicly documented. Michael in his book lays out a vision for the matching of shoes, and I think what is really important in this is to allow scientists to find others with similar interests and then give them a private space to discuss off the record.
• None if the existing services has an integration of bibliometric or scientometric data.
  
  There is plenty of data about coauthor networks within communities and also their evolution over time, mutually quoted references, and various ways to visualize research topics and their relation. I think this is relevant for scientists to know how many other people are working in their area, how it connects to other fields, who is working on making these connections, and how the field develops. Research has shown that many breakthroughs in science originate at the intersection of fields that weren’t previously known to be related, so these maps are interesting from a purely scientific perspective already. But they are also of personal use because they give researchers an idea about how their own research fits into the larger picture.
  
  Here is for example an interesting paper about pivot points in string theory. I know, the visualization isn’t all that great, but note that the paper is more than a decade old!

I could go on about how I hope that webinars will become better integrated and that conferences will come to have a better online presence since I find it extremely annoying and cumbersome that every institution is using their own registration system, but I can see that for what the software solution is concerned these are difficult to address by any one service.

What social media do you use to discuss science and how has your experience been with that?

Social Media for Scientists from Sabine Hossenfelder