Happy New Year!

Dear friends and followers of VASCO,

The New Year is here and so is the time of new hopes and dreams. Our wishes are now to set up the citizen science project as needed, and we are working hard to realise this as soon as possible. As some may have noticed, there has been lots of media news about the VASCO project lately. We appreciate very much the positive response we have got and the interest into the project. We remind the readers that we believe the ~100 transients reported in our first VASCO paper most likely represent very natural short-lived phenomena, such as big M dwarf flares, high-z supernovae and other astrophysical transients. That doesn’t make us less excited to follow up on them and trying to figure out what they actually are — astronomy is full of natural wonders. The introduction in our paper in the Astronomical Journal gives a thorough view of many natural phenomena one can camouflage as “vanished” stars in the VASCO project. With this being said, we will carefully investigate *all* possible explanations for each candidate we find in our project.

We attach some helpful links below and wish everybody a Happy New Year 2020! We stay in touch.

Original article in Astronomical Journal:


Original press releases





Happy New Year!

VASCO in The Astronomical Journal

Dear all,
It is our pleasure to announce the first VASCO paper. It has just been accepted to the Astronomical Journal and can be found on arxiv.org:

In this paper, we discuss how VASCO can help to identify objects that satisfy some typical ET techno-signatures like vanishing stars, Dyson spheres and interstellar laser communication, but also how it can help traditional astrophysics in finding interesting or weird objects and events displaying strong changes in brightness. We present the discovery of ~100 very short lived or very red transients.
VASCO in The Astronomical Journal

Article about VASCO in Forskning & Framsteg, Vol 6 2018


In the early spring, we were interviewed

about VASCO for the Swedish popular science journal, “Forskning & Framsteg” for its June issue. You can currently buy it in Pressbyrån in Sweden or online (at http://fof.prenservice.se/KodLandning/Index/?Internetkod=057-0571311&gclid=EAIaIQobChMI1PGSw46G3AIVkYKyCh35nAC4EAAYASAAEgI6J_D_BwE).

You can also read an online version: (link: https://fof.se/tidning/2018/6/artikel/jakten-efter-forsvunna-stjarnor)

— Beatriz Villarroel

Article about VASCO in Forskning & Framsteg, Vol 6 2018

What Drake’s equation says about the nature of probability

Drake’s equation (i.e. a decomposition of the probability that alien life must exist as a chain of conditional probabilities which sound more reasonable. After a beer or two. Or three) makes an interesting case for thinking about the nature of probabilities. What do we mean really when saying ‘those aliens must in all likelihood exist‘? No way it can point to a relative frequency. Maybe a propensity interpretation? But statements as ‘they tend to exist‘ make not much sense either. The only viable option – as far as I can see – is that evidence suggested by Drake should be in the eye of the beholder. Subjective. Belief-based. Bayes. In the good ol’ De Finetti sense. Earthlings and any alien civilisation far far away must be exchangeable. We are as curious for them as they for us. This seems a solid foundation for educated guessing about this.


What Drake’s equation says about the nature of probability

New questions and old observations: How the front line of astronomy benefits from its history

Considering the history of astronomy, we see that several phenomena known today were within observational reach much earlier than when they were actually discovered. Heinrich Schwabe discovered the solar cycle in the 1840s, after almost two decades of diligent telescopic observations. Numerous records of sunspots visible to the naked eye are preserved from ancient cultures, though, and it is known (see e.g. Schaefer 1991) that the number of sunspots visible to the naked eye follows the same 11 yr cycle as the relative sunspot number (found via observations with telescopes). Using suitable eye protection or taking advantage of when e.g. thick clouds dampen the sunlight sufficiently, an observer in ancient times with enough stamina could (as others have pointed out) have discovered the solar cycle.

However, just because a phenomenon is within technological reach to observe does not mean that there is sufficient awareness or interest to even ask the questions leading up to its discovery. The Sun had already been under scrutiny with telescopes for over 200 years when Schwabe made his discovery, and there is slight reason to believe that ancient solar observers would have been able to pose questions leading to a prolonged observing campaign revealing the solar activity cycle. Today, the scant ancient observations of naked eye sunspots are being collected (see e.g. Wittmann & Xu 1987) for use in modern solar studies.

What else could be hiding in ancient astronomical records? Studies of transient celestial phenomena such as comets, meteor showers and supernova explosions have used pre-telescopic observations to gain valuable insights. As astronomy develops, new questions are raised, and even gamma-ray bursts (GRBs) have been addressed from the perspective of historical records. These short (seconds to hours), extremely luminous bursts of gamma rays happen anywhere in the sky and are found at a rate of  about one per day. GRBs usually occur at distances of billions of light years and likely arise from either certain types of supernovae or from merging neutron stars. Their optical afterglow is usually invisible to the naked eye, with at least one clear exception. The GRB 080319B, observed on 2008 March 19, reached peak visual magnitude 5.3 and was within naked eye visibility for about 30 sec (Racusin et al. 2008).

This GRB inspired Strom, Zhao & Zhang (2012) to see if any historical record of other naked-eye GRBs could be found, also asking what any such historical record could tell us. Using statistics of optical counterparts of GRBs from 1997-2010, they demonstrate that at least 10 GRBs of about the same magnitude as GRB 080319B happen per century, and that 2 GRBs per century should reach magnitude 3 (a brightness comparable to the faintest star in the Big Dipper). A handful of times per millennium, they estimate, a magnitude 0 GRB (bright as Vega) could appear in the sky. While unlikely, a naked-eye observer with good knowledge of the night sky could notice a visual GRB during the seconds or minutes it is visible. Vetting old Chinese records, Strom, Zhao & Zhang found a handful of candidate events, an interesting one coming from 1855 August 16 (of a “star of red color” visible “in the southeast” for “about 7 minutes”). The vagueness of the record prevents further follow-up, though. Discussing the use of a possible recovery of a naked-eye GRB from historical records, Strom, Zhao & Zhang argues that a study of the GRB remnant after several centuries could maybe benefit. Even without a GRB remnant identification, they point at how identification of a historical naked-eye GRB could help constrain the rates of such rare events.

With the above examples from investigations inspired by observations made with the naked eye throughout history, it is staggering to think about what can be learned from renewed investigations of such a rich material as the photographic plates taken at observatories around the globe during the past century and a half. While our knowledge will never be complete, we nevertheless have the ability today to address astrophysical questions undreamt-of when the plates were taken decades ago. Extreme phenomena and beautiful patterns of nature likely hide within plain sight in photographic plates and other records from the recent past of astronomy. The VASCO (Vanishing & Appearing Sources during a Century of Observations) project intends to explore this.

Anders Nyholm

New questions and old observations: How the front line of astronomy benefits from its history