2020-08-31 (Monday)

Today, I learned about:

There are so many interesting things happening outside our small Earth, in the vast space of the Cosmos. I recently took a course on the edX MOOC (massive open online course) from the mighty MIT, Massachusetts Institute of Technology. The course had the title “Introduction to Aerospace Engineering: Astronautics and Human Spaceflight.”

What made the course so exceptionally interesting was, besides the contents with plenty of video clips further to the traditional Power Point style lectures, that the teacher of the course was no one less than an ex-NASA astronaut, Jeffrey A. Hoffman. His first space flight was in the first servicing mission of the Hubble telescope in December, 1993, and after that he participated in four more missions to the international space station ISS. Only a live astronaut can make a course like this even more interesting by telling his personal experience of those missions. See also reference #1 below.

Astronauts Franklin Story Musgrave and Jeffrey Hoffman install corrective optics during the first service mission to the Hubble telescope in December 1993. Photo courtesy by NASA.

Another interesting fact about the big wide space was published in June, 2020, by Popular Mechanics. It is a story about how a pulsar prepared itself to eat up a nearby star and released an outburst of cosmic X-rays thousands of times brighter than the sun!

Astronomers captured the “power up” sequence of a pulsar right before it gobbled up gas and dust from a nearby star and shot a burst of X-rays into space. It is the first time they have captured this entire process before. The research, astronomers say, will help us understand how pulsar outbursts form. Photo courtesy by NASA.

That’s what I learned in school !


1: Hubble Space Telescope, Servicing Mission 1

*: What did you learn in school today ?

2019-05-31 (Friday)

Today, I learned that:

I owe a big apology to all my faithful readers for having been absent with new posts for almost two months, so let me make it up today with a quite few interesting facts:

1. Image of a black hole

During the month of April, we received the astonishing news that astronomers had finally managed to catch a black hole on film. The image was captured by the Event Horizon telescope (EHT), a network of eight radio telescopes spanning locations from Antarctica to Spain and Chile, in an effort involving more than 200 scientists. Read more about it in ref. #1 below.

The image of a black hole captured by the Event Horizon Telescope. Photo by the EHT Collaboration team, consisting of 200 astronomers at eight different telescope sites.

2. Late Easter (continuation from earlier post)

In my post of 2019-03-05 I wrote about the late date of Easter this year, and as you may remember my friend, the German-Swedish meteorologist André Franke explained it all for us.

However, I have received comments about this subject. In 2019, the March equinox occurred on March 20, and there was a full moon already the next day, March 21. So, why was not Easter Sunday celebrated on March 24? André can explain that, as well. It is quite complicated, but here is the short explanation:

It all started in year 325, when the First Church Council of Nicaea among other things decided that the March equinox should always fall on March 21, and then Easter Sunday would always be the first Sunday following the first full month after the March equinox. But as we know, the Earth’s rotation around the Sun is not exactly 365 days. It is approximately 6 h more, and that causes that the fixed March equinox day is not always the same actual, astronomical day for the same equinox, as happened this year.

If you want know the long story, take a look at reference #2. Unfortunately, it is written in Swedish, but there are many other sources around the internet that can tell the same story.

3. Baarle

Baarle is a village right on the border between the Netherlands and Belgium. 91 % of the total area of the village belongs to the Dutch, the rest is Belgian. But it is not a clean cut, there are in fact 16 Belgian exclaves within the Dutch territory, and they in turn surround seven Dutch areas. See also reference #3 below. Thanks to Radio Sweden’s Andreas Liljeheden for yet another idea to an interesting blog fact, see also ref. 4 below! (You may remember Andreas’s earlier contribution to my blog on 2018-10-20, when he presented the donkey steps in the EU headquarters in Brussels.)

Andreas Liljeheden posing on a selfie in Baarle, in a street where both the Dutch and Belgian flags are blowing in the wind side by side.

4. Different maps of the world

One of my interests is maps, traditional, historic, different kinds of maps – you name them! It is therefore a great pleasure for me to present a total of 45 different maps of the world, the big majority of them are without doubt something you have never seen before. Click on the link of ref. #5 below and start being amazed. (I like maps #1, 2, 7, 8, …)

That’s what I learned in school !


1: Black hole picture captured for first time in space breakthrough

2: Vårdagjämning, fullmåne och ovanligt sen påsk: därför ser almanackan underlig ut 2019

3: Baarle

4: Andreas Liljeheden om ett avgörande EU-val

5: 45 Amazing World Maps

*: What did you learn in school today ?

2016-04-17 (Sunday)

Today, I learned that:

In the Guizhou province in the Southwest of China, an impressive construction is underway. It is the Five hundred meter Aperture Spherical Telescope (FAST). This exact location was chosen because it is very well shielded from magnetic disruptions, the ground is both stable enough to hold the structure and porous enough to drain away water and protect the telescope.

When concluded later on in 2016, FAST will be the largest single-aperture radio telescope in the world, with a 500 meter diameter, 60 % larger than the current largest one, the Arecibo Observatory in Puerto Rico. It will be comprised of 4,500 triangular panels, which when combined with an active adjustable reflector, will enable scientists to observe a larger area of space in greater fidelity than any telescope before it. See also reference #1 below.


The Five hundred meter Aperture Spherical Telescope, currently under construction in Guizhou province, China. Photo credit: ChinaFotoPress / Getty Images

And today I also learned that within the next few months, Sweden will exhibit a topological map with a resolution 25 times greater than the current one. The older aerial photos will give way to a modern method where an airplane flying on an altitude of 2 km beams a laser over a 1,5 km wide area, thus permitting a ground resolution of 2 m! Not bad, considering that Sweden has a total area of 450 000 km2. The new map has already revealed surprising archeological facts about the Swedish landscape that were unknown before. Reference #2 (in Swedish) gives more details.

And finally, why is everybody talking about “April in Paris”? I say “April in Tokyo”, with cherry trees in blossom like the one in the header photo. I had left Beijing a couple of hours earlier, but before that I had one of the biggest surprises ever in my life. While waiting for my flight to be called out, I visited the VIP lounge at the Beijing airport to check e-mails, and there I met a good old friend from the same small village where we both were born. He had been in China together with his wife to inaugurate a new production plant. Now I perfectly understand the meaning of the expression “It is a small world we live in!”


Arriving in Tokyo on Sunday afternoon 2005-04-17, my sister-in-law and her family brought me to see some interesting sights and take these photos. The ones in the top row are from the lush gardens of Edo Castle, and the ones in the lower row are also from downtown Tokyo, giving both a birds-eye view of the center and a street view of the Kabuki-za in the Ginza district. For more information, see references #3, 4 and 5 below.

… That’s what I learned in school !


1: An otherworldly visitor nests in rural China

2: Ny höjdmodell över Sverige

3: Edo Castle

4: Ginza

5: Kabuki-za

+: What did you learn in school today ?

2016-03-20 (Sunday)

Today, I learned that:

Astronomy continues to be such a fascinating science! Today’s podcast from 365 days of Astronomy deals with the latest feat by the NASA/ESA Hubble Space Telescope. Recently, it was able to reach out to photograph a galaxy that lies at a distance bigger than we have ever traveled before, 13,4 billion light-years. More about this amazing fact can be found in references # 1 and # 2 below.


This photo is a look 13,4 billion years back in time, when our Universe was only 400 million years old. The NASA/ESA Hubble Space Telescope has broken the record for how far back we have been able to look. The galaxy that is the star (!) of this photo is named GN-z11.

And speaking about celestial objects, today we also learned that the fear of getting sick by the Sun which has led to that many people are trying to hide from it can have negative consequences on our body. An article in the April issue of Journal of Internal Medicine presents a study made in the South of Sweden:

“There were 2545 deaths amongst the 29 518 women who responded to the initial questionnaire. The authors found that all-cause mortality was inversely related to sun exposure habits. The mortality rate amongst avoiders of sun exposure was approximately twofold higher compared with the highest sun exposure group, resulting in excess mortality with a population attributable risk of 3 %. The results of this study provide observational evidence that avoiding sun exposure is a risk factor for all-cause mortality. Following sun exposure advice that is very restrictive in countries with low solar intensity might in fact be harmful to women’s health.”

See references #3 and #4 below for more information.

And speaking once more about the Sun, as you probably already know today occured the March Equinox, when the day and night are practically of equal length all over the world. But if you live on the Northern Hemisphere, then you can look forward to an increased amount of day light during the coming three months, culminating with the Solstice around mid-summer. (The situation for us in the Southern Hemisphere is of course inverse, the days are slowly getting shorter now …) Reference #5 below has more information about the Equinox.

… That’s what I learned in school !


1: Hubble Breaks The Cosmic Distance Record, 365 days of Astronomy

2: Hubble Breaks The Cosmic Distance Record, Space Telescope

3: Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort

4: För lite sol kan vara skadligt

5: Equinox

+: What did you learn in school today ?

2016-01-31 (Sunday)

Today, I learned that:

Astronomers in Babylon used mathematical methods already during centuries before the start of the Christian era to track movements of Jupiter. In order to do so, they were taking the first steps from geometry toward calculus to figure out the distance it moved across the sky. Such methods with trapezoides were only used much later in Europe, during the 14th century AD.


Babylonian clay tablet. Photo: Trustees of the British Museum/Mathieu Ossendrijver

The proof for this can be found in four small clay tablets, which have been stored in the British museum for quite some time. However, it was only recently that Mathieu Ossendrijver from Humboldt University in Berlin was able to decypher their contents.

The interesting story can be found in the two references below.

… That’s what I learned in school!


1: Babylonians Were Using Geometry Centuries Earlier Than Thought

2: Babylonierna räknade också med grafer

+: What did you learn in school today ?

2016-01-27 (Onsdag)

Idag lärde jag mig, att:

Idag är det många som intresserat följer med vad som händer i vårt kosmos. Många känner till Stephen Hawking och hans teorier om svarta hål, men visste ni att det redan i början på 1900-talet fanns en svensk som hörde till de stora inom astronomin?

Han hette Knut Lundmark, föddes i Älvsbyn i Norrbotten år 1889, och studerade vid Uppsala universitet, där han dokterade i astrofysik, på en avhandling om Andromedagalaxen. Han blev så småningom professor vid Lunds universitet, där han också var flitigt engagerad i olika populärvetenskapliga sammanhang. Under långa tider verkade han också vid olika observatorier i USA.

Hans största bidrag till astronomin, publicerat redan 1930, men avslöjat först under 2015, var att det i universum fanns mycken “mörk materia” som vi inte kunde förklara då, och det gäller faktiskt fortfarande. Och det var Knut som först postulerade att universum befinner sig i expansion, fem år innan Edwin Hubble.


Knut och Birgitta Lundmark. Foto: Norrbottens Museum

Knut och hans fru Birgitta brevväxlade mycket och ömsint under alla år som de var åtskilda av hans forskningsarbeten, och i radioprogrammet Släktband som sändes den 25 januari omtalas deras brevsamling, se referens 4 nedan, väl värt att lyssna på! Karin Tjernström på Norrbottens Museum rekommenderar också ett SR-program från 1948, där Harry Martinsson och Knut Lundmark samtalar om universum, referens 5 nedan.

… Slut för idag, tack för idag!

(This post in Swedish deals with the Swedish astronomer Knut Lundmark, the first scientist to propose the existence of dark materia and that the universe is expanding.)


1: Knut Lundmark på Wikipedia

2: Astronomiska Sällskapet Tycho Brahe om Knut Lundmark

3: Lundaprofessorn som upptäckte den mörka materian

4: Kärleksbrev i våra arkiv

5: Samtal om universum med Harry Martinson

+: What did you learn in school today ?

2016-01-22 (Friday)

Today, I learned that:

Space lovers are having a week that is nothing else but fabulous. We already saw the first flower grown in zero gravity. And now, going from plant to planet, here comes other equally exciting news.

Astronomers at California Institute of Technology suggest that our solar system has a ninth planet. By measuring dwarf plants in the Kuiper Belt, farther away from us than Pluto, they suggest that their irregular movements may be due to influence by another, still unknown planet, that they call Planet Nine. If that is true, this planet is 5 to 10 times bigger than Earth and has an orbit around the Sun that takes 10.000 to 20.000 years to complete.

This reminds me of how Pluto was once discovered. In the 1840s, Urban Le Verrier predicted the position of Neptune by how Uranus had its orbit disturbed by another celestial object, and once Neptune had been discovered, there was a similar discussion about yet another planet, beyond Neptune. In 1909, Percival Lowell and William H. Pickering suggested the position of such a Planet X, until finally Pluto was confirmed by Clyde Tombaugh in 1930.

And speaking about planets, the coming two weeks will give us a festival of planets, when all five planets March, Venus, Jupiter, Mercury and Saturn will be aligned in the early morning sky and visible with naked eye! The reference below gives more details about that, and thanks also to Cecilia for the hint!

… That’s what I learned in school!


1: Astronomers may have found the Solar System’s 9th planet

2: Evidence for a distant giant planet in the solar system

3: Pluto

4: See all five naked-eye planets gathered in the morning sky

+: What did you learn in school today ?