Livestream of Total Solar Eclipse 2024

The US National Science Foundation (NSF) will be livestreaming the total Solar Eclipse of 2024. Here is the blurb from them:

Don't just watch the eclipse — explore it. On April 8, the U.S. National Science Foundation and the NSF National Solar Observatory are hosting an educational livestream all about the science of the sun.  

The livestream is a free resource that educators can use in their classrooms to share the excitement of science.  

You'll hear from scientists about the unique experiments happening during the eclipse. As we count down to the moment of totality, you'll learn about:  

• The different layers of the sun, from the core to the corona. 
• The world's largest, most advanced solar telescope.  
• How massive solar eruptions generate space weather. 

It all happens on YouTube on April 8 starting around 11 a.m. PDT/noon MDT/1 p.m. CDT/2 p.m. EDT.

 https://www.youtube.com/live/qAZmtbTTQAE?si=AKttYJOJT32g-Q3O

 

Since When Does A "Proposal" Become "Evidence"?

It's one of the reasons why I groan at popular media's reporting of science.

This article is reporting on a paper that proposes a possibility of finding evidence of large-scale symmetry breaking from the  data ".. in current and upcoming surveys such as those undertaken by Dark Energy Spectroscopic Instrument, the Euclid satellite, and the Vera C. Rubin Observatory.... ". Yet, the article is trumpeting the "Incredible new evidence...." as if it has been found. This is similar to accepting speculation as the truth.

Over-selling and over-hyping science does no one any good, other than making it a click-bait.

Z.

The First 12 Months of the James Webb Space Telescope

Many of us knew that it would be a significant instrument. We just didn't know that in its early days, it would make this many discoveries.

In case you were asleep for most of the past 12 months, here is an article that will highlight some of the groundbreaking discoveries made by the JWST. It will not be hard to guess that there will be more earth-shattering (universe-shattering?) discoveries to be made in the next 12 months.

Zz.

Blackholes The Source Of Dark Energy?

Can blackholes at the center of galaxies be the source of the dark energy that we have been detecting?

That seems to be the conclusion based on two recently published papers [1,2]. Both of these are open access papers, so the full papers are available to everyone.

You may read an explanation and review of the papers at the AAS news website. The implication here is that if this is true, then dark energy is not something exotic or new since it can already be explained with General Relativity.

Now, if only we can find those pesky dark matter.... if they exist.

Zz.

[1] D. Farrah et al., Astrophy. J. Lett., v.944, p.L31 (2023).

[2] D. Farrah et al., Astrophy. J., v.943, p.133 (2023).

How Fast is Gravity?

 Don Lincoln has produce another fun video on the speed of gravity.

SPOILER: It has the same speed as the speed of light!

But what is more interesting in this video is a brief description of LIGO and gravitational interferometry and how gravitational waves are detected.

Enjoy!

Zz.

The Future of CMB Exploration

You would think that once the cosmic microwave background (CMB) has been discovered and studied, that was the end of it. That is not how science typically works, especially on something that has such a rich amount of information as the CMB.

This article reports on the next proposed major research effort in the US in further studying the CMB and refining the measurements that we currently have. The article gives you a good over view of what we currently know about the CMB, what we wish to extract out of it, and how it can be done. This appears to be a joint effort between two major science funding agencies in the US: the US Dept. of Energy and the US National Science Foundation, and will have an estimated cost of $650 million.

As someone who likes to include contemporary and most recent relevant news into my lessons, this will be another item that I will include in my Intro to Astronomy class.

Z.

My Favorite Web Applications - Part 1

I've used online web applications as supplement or enhancement to the class material, but during the pandemic when we went remote, I relied on them even more. In fact, I remember a couple of days where I did a lot of surfing and searching to find suitable web applications for various activities and topics, simply to catalog on the various things that are out there that I could use for my classes.

Over the months and years, I have a bunch of web applications that I consistently go to that I find to be quite useful. These can either be simulations to illustrate a physical concept, or virtual activities or experiments that mimic what students may perform in a lab.

In a series of posts, I will show what I've used and how each one was used, especially during a remote class. Maybe someone might find one or more of them useful, or might see it being used in a different way. Better yet, maybe someone has a better web application for the same task. I definitely like to hear that!

To start of, here is my most favorite web application to demonstrate the phases of the moon and why we, on Earth, see what we see. Despite the simple-looking screen, this webpage is choke-full of information. The biggest part of the screen shows the location of an observer on Earth, the location of the Moon, and the position of the Sun. You can manually click and drag the observer and the moon to get them to move to any valid position, or run the animation.

But don't ignore the two smaller animation on the right side of the screen. The top animation shows the moon phase that the observer sees at that time of the month. The lower animation shows what the observer sees at that time of the month and the time of the day. It indicates the positions of the moon and the sun at that particular time of day.

This is a very useful application to get students to understand why we see various phases of the moon, why we see the moon in a particular position in the sky at certain time of the month, etc. I tend to let the student play with the application for a while and then ask them to use the application to answer a series of questions. For example, what is the most likely day of the month for you see a full moon directly above your head at midnight? This is what the student should set up with the application to answer this question.

 

Another example was opportunistic because the Muslim's fasting month started sometime during the semester, and it was a common practice (it still is in many parts of the Muslim world) for people to look for the crescent moon at sundown to signify the start of their fasting month. So I also ask for when is it most likely to see a waxing crescent at sundown?

One of the best thing about this app is the ability to make the students realize, if they haven't already, that they should and can see the Moon during the day, i.e. when the Sun is also in the same side of the sky as the Moon! This allows use to discuss the often-mistaken idea that the phases of the Moon are due to the shadow of the Earth on the Moon from the Sun. We can also carry a more advanced discussion on why we don't see eclipses of the Sun and the Moon every month, especially if they have understood what this web application seems to convey.

I've looked at other websites demonstrating and explaining phases of the Moon, but to me, this is the best one out there so far.

Zz.

Media Reporting Failed Basic Central Force Motion Mechanics

This news report on The Telegraph written by Joe Pinkstone about the James Webb Space Telescope reaching its final position has a basic flaw that should be easily spotted by any intro physics student who has understood basic central force/circular motion topic.

It will stay at its current position, Lagrange 2 (L2), for its entire operational lifespan, which is expected to be around 20 years. L2 is a gravitational stable point on the other side of the Earth from the Sun, where the pull of the two bodies cancels out.

No, the pull due to the Earth and the Sun does NOT "cancels out", because if it does, then there is no centripetal force to keep the telescope to orbit around the sun! 

Rather, this is the location where the sum of the gravitational forces from the Sun and the Earth provides just the right centripetal force to keep the telescope in orbit around the Sun at the same angular speed as the Earth. It will always be on the opposite side from the Sun with respect to the Earth. You can read more explanation on what is this Lagrange2 (L2) point at the NASA website here.

This is the type of mistake that we expect to see in General Physics classes, not in major news media.

Zz.

Using Science To Teach Students In The Art Of Falsifying An Idea

The climate of fake news and anti-science during the last few years have given me the impetus to be more conscious and deliberate in alerting my students on how we analyze something, on making rational judgement based on evidence, and how we come to such-and-such conclusions. To me, the issue of believing in fake news and accepting something based on flaky evidence does deeper than what it seems. It boils down to the inability to systematically and analytically evaluate the validity of something. This inability is really a serious issue and could be the root cause of what we are seeing today.

This type of skill is exactly what we use and practice all the time in science. So when I get a group of students, especially if they are non-science students who are taking the course only to fulfill their science credits, then I can't waste the opportunity to instill in them this invaluable technique and methodology that are often used in science.

Using the period where the pandemic forced us to teach remotely, I made extensive use (and still do) of the discussion forum. This is one form of student engagements that many online training courses have deemed to be essential in making sure that students feel connected and engaged with not only the subject matter, but also with other students. This medium gave me the opportunity to get the students to think things through and to present logical and rational arguments.

One of the topic that I presented was to require them to critically address a belief about the cause of the Earth's four seasons. We were going over the reason why we (at about latitude 41 degrees North) experience seasons. I presented a topic whereby someone claims that since the Earth orbits the Sun in a slight elliptical orbit, the seasons are caused by the varying distances between the Earth and the Sun, meaning that when the Sun is closest to the Earth, we have summer, and when the Sun is farthest from the Earth, we have winter.

The task was for the students to come up with typical and common everyday observations and/or knowledge to show why this idea is wrong. In other words, find a very direct and convincing way to falsify the argument.

I thought this was a straight-forward assignment and discussion topic. Unfortunately, I was quite surprised that almost 3/4 of the students didn't fulfill the briefs. What they did instead was to give the explanation for the cause of the seasons, which is the tilt of the Earth's spin as it goes around the Sun. While this is the correct explanation, it does not falsify the original argument. I tried to tell the students that what they did was to present to this person an alternative explanation on why the seasons happen, but they haven't shown evidence why the original premise was wrong! They have not falsified the first idea.

When we do that in an argument/discussion, the person who holds that idea can easily say "All you have done is showed another possible explanation. You haven't proven to me why my idea is wrong. So why should I change my mind?"

Providing an alternative explanation, even if it is the correct one, is distinctively different than falsifying an idea. In falsifying an idea, you do not need to actually have an alternative, correct explanation. In this case, you really don't need to know that the Earth's tilt is the cause of the seasons on Earth. All you need is to examine the original claim, and find evidence that contradicts that claim. In this case, what you can do is assume that it is true, that the seasons are caused by Earth's varying distances from the Sun. If that is true, then the entire Earth would have the same season at the same time of the year, because the entire Earth is at the same distance away from the Sun. Yet, it is common knowledge that Australia, New Zealand, South America and Antartica are in their deep winter freeze while we in the Northern Hemisphere are basking in our summer heat. This observation is clearly contradictory to the original claim, which means that this is a falsification of that idea. It carries no other "baggage", i.e. it doesn't promote an alternative explanation on the cause of Earth's seasons.

It found it challenging trying to convey this message to the students. They learned about the Earth's tilt and the cause of the seasons, and when they were given this topic, they immediately jumped on providing the explanation that they just learned (and understood) without thinking about how to actually address the topic of the discussion and knowing the difference between falsifying an argument versus providing an alternative explanation.

Sadly, the same situation happened again later in that semester when I brought another scenario for them to address: the claim that the phases of the moon are due to Earth's shadow of the light from the Sun. Once again, they were asked to falsify the claim, and once again, more than half of the students provided an alternative explanation on the cause of Moon phases rather than falsifying the idea.

In teaching science courses to non-science majors, I've grown more skeptical about the public's ability to analyze something. What I have observed regarding the "controversy" surrounding vaccines, the wearing of face masks, and even climate change, reinforced my skepticism about someone 's ability to either think things through, or even know what a valid evidence is. My post on the nurse who claimed that the COVID vaccine makes her becoming magnetized is one such example. Something that should have been easily checked and verified by a high-school physics student now somehow is gaining traction. That claim can be easily falsified (and have been), even by people without much scientific training and without knowing any alternative explanation on why certain objects might stick to one's body.

It requires skills to look at an idea, analyze it thoroughly, and rationally argue on its validity or its fault. It also requires skills to know what are valid evidence and what are not. Often times people confuse opinions and conclusions with facts/evidence. Talking heads on TV often spew out opinions that a lot of people mistaken for facts. In a science class, it is more important than ever that instructors make a deliberate effort to show the process of how a scientific idea becomes accepted, what kind of evidence would be considered to be scientific (why do we have to measure the forces at various extensions when just one is sufficient to find the value of the spring constant in Hooke's law experiment?), and how to challenge an idea and show that it may not be correct.

A science education is now more important than ever, not just for the scientific content, but also for the skills that come with it.

Zz.

The Sad Ending of Aricebo Observatory

It was less than a month ago, on a Nov. 19, 2020 report, that the National Science Foundation announced the closure of the famed Aricebo Observatory in Puerto Rico due to structural and safety problems. Unfortunately, on Dec. 1, 2020, the collapse of the central structure happened, with dramatic footage released by the observatory.

While the famed telescope is gone, it will live forever in many footage from movies and tv shows. This is in addition to the numerous scientific discoveries that it has made throughout its operation.

Zz.

Death by Spaghettification

This is probably a rather unpleasant way to die, but it may also be the most spectacular way.

Astronomers have observed for the first time the ripping apart of a star as it got too close to a massive blackhole.

“When an unlucky star wanders too close to a supermassive black hole in the centre of a galaxy, the extreme gravitational pull of the black hole shreds the star into thin streams of material,” explains study author Thomas Wevers, an ESO Fellow in Santiago, Chile, who was at the Institute of Astronomy, University of Cambridge, UK, when he conducted the work. As some of the thin strands of stellar material fall into the black hole during this spaghettification process, a bright flare of energy is released, which astronomers can detect.

What is even interesting is that the unfortunate star is about the same size as our sun. So you kinda feel a bit for the poor thing.

But of course, all of these happened quite some time ago. It is probably quiet now in that part of the universe.😁

Zz.

Lightest Known Blackhole, Or Largest Known Neutron Star?

I tell ya, after years and years of searching for gravitational waves, and then finally discovering it several years ago, the LIGO-Virgo gravitational waves detector has become an amazing astronomical/astrophysical observatory, making one amazing discovery after another. The existence of such gravitational waves are no longer in doubt that they are now being used as a means to detect other astronomical events.

This is one such case where it appears that a 2.6 solar-mass unknown object collided with a 23 solar-mass blackhole.[1] If this 2.6 solar-mass object is a blackhole, it will be the lightest known blackhole. If it is a neutron star, it will be the heaviest known neutron star. Both scenario will require a reworking of current theories, because a blackhole that light, or a neutron star that heavy, was thought to be unlikely.

Neutron stars and stellar black holes are the final stages of evolution for large stars – with black holes being more massive than neutron stars. In theory, the maximum mass of a neutron star is about 2.1 solar masses. However, there is some indirect evidence that more massive neutron stars could exist. There is little evidence for the existence of black holes smaller than about 5 solar masses, leading to a mass gap in our observations of these compact objects.

What is intriguing about the August 2019 merger – dubbed GW190814 – is the mass of the smaller object, which appears to fall within this gap. “Whether any objects exist in the mass gap has been an ongoing mystery in astrophysics for decades,” says Charlie Hoy of the UK’s Cardiff University, who played a key role in analysing data from the detection and writing the paper that describes the observation, which has been published in The Astrophysical Journal Letters. “What we still don’t know is whether this object is the heaviest known neutron star or the lightest known black hole, but we do know that either way it breaks a record.”

The actual paper is available to be read for free here since it is an open access article.

Like I had said to the students in my astronomy classes, this is going to go down as the golden age of astronomy. Since the beginning of human history, we only had light as our only detector of the heavens. Now, we have not only neutrinos and high-energy cosmic rays, but also gravitational waves as our means to look at the heavens. We have three different and separate ways to look at our sky!

Zz.

[1] R. Abbott et al., The Astrophysical Journal Letters,896:L44(20pp), 2020.

DESI Begins

A new eye on the sky is about to add to our knowledge of dark energy.



It's interesting that in the list of funding agencies, NASA is absent. This goes to show you that many of these research activities that seem to be "astronomy-related" are not the sole domain of NASA. In fact, the area of particle-astrophysics is more closely related to particle physics than astronomy.

The video didn't clarify explicitly that in looking at the "spectrum" of light from each of these celestial bodies, one gets the radial velocity of these bodies with respect to us (i.e. via the amount of redshift), not its distance from us. That last piece of information can only be "deduced" using the radial velocity and the Hubble equation, i.e. the Hubble constant, a number that is still being refined.

Still, this new telescope is going to be quite exciting in revealing more of the mysteries of dark energy.

Zz.

Big Bang Disproved?!

Of course not! But this is still a fun video for you to watch, especially if you are not up to speed on (i) how we know that the universe is expanding and (ii) the current discrepancy in the measurement of the Hubble constant via two different methods.



But unlike politics or social interactions, discrepancies and disagreement in science are actually welcomed and a fundamental aspects of scientific progress. It is how we refine and polish our knowledge into a more accurate form. As Don Lincoln says at the end of the video, scientists love discrepancies. It means that there are more things that we don't know, and more opportunities to learn and discover something new.

Zz.

First Images of a Black Hole

After a week of rumors and build-up, the news finally broke and it is what we have been expecting. It is the announcement that we finally have our first image of a black hole.

The first direct visual evidence of a black hole and its “shadow” has been revealed today by astronomers working on the Event Horizon Telescope (EHT). The image is of the supermassive black hole that lies at the centre of the huge Messier 87 galaxy, in the Virgo galaxy cluster. Located 55 million light-years from Earth, the black hole has been determined to have a mass 6.5-billion times that of the Sun, with an uncertainty of 0.7 billion solar masses.

You can actually read the papers that were published related to this announcement, so you can find a lot more details there.

Well done, folks!!

Zz.

Gravitational Red Shift Shows That Einstein Is Right Once More!

Albert Einstein's General Relativity is 3-for-3 this year so far! We already had GR passing its first galactic-scale test, and then we had the verification of the strong equivalence principle. This time, observation of light from a star in our Milky Way passing near a supermassive black hole has shown the predicted gravitational red shift. Holy Cow, Batman!

The team compared the position and velocity measurements from GRAVITY and SINFONI respectively, along with previous observations of S2 using other instruments, with the predictions of Newtonian gravity, general relativity and other theories of gravity. The new results are inconsistent with Newtonian predictions and in excellent agreement with the predictions of general relativity.
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The new measurements clearly reveal an effect called gravitational redshift. Light from the star is stretched to longer wavelengths by the very strong gravitational field of the black hole. And the change in the wavelength of light from S2 agrees precisely with that predicted by Einstein’s theory of general relativity. This is the first time that this deviation from the predictions of the simpler Newtonian theory of gravity has been observed in the motion of a star around a supermassive black hole.

A copy of the paper (or maybe a preprint) can be found here.

It bears repeating: the more they test it, the more convincing it becomes!

Zz.

Neutrinos Come Knocking For Astronomy

I feel as if these are the golden years for astronomy and astrophysics.

First there was the discovery of gravitational waves. Then a major astronomical event occurred, and we were able to detect it using the "old" standard technique via EM radiation, and via the detection of gravitational waves from it. So now astronomy has two different types of "messengers" to tell us about such events.

Well now, make way for a third messenger, and that is ubiquitous neutrinos. Two papers published in Science last week detected neutrinos (along with the accompanying EM radiation) from a "blazer". The neutrino detection part was made predominantly at IceCube detector located in the Antarctica.

Both papers are available as open access here and here. A summary of this discovery can be found at PhysicsWorld (may require free registration).

Zz.

What Astronomers Wish You Know About Dark Matter And Dark Energy

If you do a search of this blog, you will encounter numerous entries on both "dark matter" and "dark energy". It is something I've covered quite often, mainly because it is still an ongoing and active research area in astrophysics/astronomy/cosmology. Even high-energy physics/elementary particle physics is getting into the picture with particle astronomy.

In this article, Ethan Siegel gives you a condensed version of what "dark matter" and "dark energy" are, and what you need to know about them. But more importantly, if you think that you can discard them, you need to do more than just say that they are not needed.

It wasn't always apparent that this would be the solution, but this one solution works for literally all the observations. When someone puts forth the hypothesis that "dark matter and/or dark energy doesn't exist," the onus is on them to answer the implicit question, "okay, then what replaces General Relativity as your theory of gravity to explain the entire Universe?" As gravitational wave astronomy has further confirmed Einstein's greatest theory even more spectacularly, even many of the fringe alternatives to General Relativity have fallen away. The way it stands now, there are no theories that exist that successfully do away with dark matter and dark energy and still explain everything that we see. Until there are, there are no real alternatives to the modern picture that deserve to be taken seriously

It might not feel right to you, in your gut, that 95% of the Universe would be dark. It might not seem like it's a reasonable possibility when all you'd need to do, in principle, is to replace your underlying laws with new ones. But until those laws are found, and it hasn't even been shown that they could mathematically exist, you absolutely have to go with the description of the Universe that all the evidence points to. Anything else is simply an unscientific conclusion.

Zz.

How Do We Know Blackholes Exist?

If you don't care to read in detail on the physics, and have the attention span of a 2-year old, this is Minute Physics's attempt at convincing you that blackholes exist.



Zz.

Determining The Hubble Constant

Ethan Siegel has a nice article on the pitfalls in determining one of the most important constants in our universe, the Hubble constant. The article describes why this constant is so important, and all the ramifications that come from it.

As you read this, notice all the "background knowledge" that one must have to be able to know how well certain things are known, and what are the assumptions and uncertainties in each of the methods and values that we use. All of these need to be known, and people using them must be aware of them.

Compare that to the decision we make everyday on things we accept in social policies and politics.

Zz.