The Secretary-General's son Gabriel Lougou Unicef.org đșđłđšđ«đ©đ°.
116 posts
Here is a masterpost of MOOCs (massive open online courses) that are available, archived, or starting soon. I think they will help those that like to learn with a teacher or with videos. Â You can always check the audit course or no certificate option so that you can learn for free.
ASL University
Sign Language Structure, Learning, and Change
Arabic Without Walls
Madinah Arabic
Moroccan Arabic
Depi Hayk
Learn Bangla (Register to see course)
Parla.Cat
Speak Cat
Beginner
Chinese for Beginners
Chinese Characters for Beginners
Chinese for HSK 1
Chinese for HSK 2
Chinese for HSK 3 I & II
Chinese for HSK 4
Chinese for HSK 5
Mandarin Chinese Level I
Mandarin Chinese Essentials
Mandarin Chinese for Business
More Chinese for Beginners
Start Talking Mandarin Chinese
UT Gateway to Chinese
Intermediate
Intermediate Business Chinese
Intermediate Chinese Grammar
Mandarin for Intermediate Learners I
Introduction to Dutch
Online Courses here
Resources Here
Faroese Course
A Taste of Finnish
Beginner
AP French Language and Culture
Elementary French IÂ &Â II
Français Interactif
Vivre en France - A1
Vivre en France- A2
Intermediate & Advanced
French Intermediate course B1-B2
Passe-Partout
Travailler en France A2-B1 Â Â Â Â Â Â Â Â Â Â
Vivre en France - B1 Â
Beginner
Deutsch im Blick
German Project
German at Work
Goethe Institute
Introduction to Gwichâin Language
Biblical Hebrew
UT Austin
A Door into Hindi
Virtual Hindi
Icelandic 1-5
Learn Indonesian
Irish 101, 102, 103, 104, 105, 106, 107
Beginner
Beginnerâs Italian I
Introduction to Italian
Intermediate & Advanced
AP Italian Language and Culture
Intermediate Italian I
Advanced Italian I
Genki
Japanese JOSHU
Japanese Pronunciation
Marugoto Courses
Tufs JpLang
Beginner
First Step Korean
How to Study Korean
Introduction to Korean
Learn to Speak Korean
Pathway to Spoken Korean
Intermediate
Intermediate Korean
Introduction to Norwegian I, Norwegian II
Norwegian on the Web
Easy Persian
PersianDee
Online Course
Pluralidades em PortuguĂȘs Brasileiro
Beginner
A1 Course
I speak Russian
Intermediate
B1 Course
B1+ Course
B2.1 Course
B2.2 Course
Beginner
AP Spanish Language & Culture
Basic Spanish I, Spanish II
Spanish for beginners Â
Spanish for Beginners 1, 2, 3, 4, 5, 6
Spanish Vocabulary
Advanced
CorrecciĂłn, Estilo y VariacionesÂ
Leer a Macondo
Online Course
Online Course
Read Ukrainian
Speak Ukrainian
Beginnerâs Welsh
Discovering Wales
YorĂčbĂĄ YĂ© Mi
Ancient Languages
More Language Learning Resources & Websites!
Last updated: May 2019
Dr. Yolanda Shea is a climate scientist at NASA's Langley Research Center. Sheâs the project scientist for the CLARREO Pathfinder (CPF) mission, which is an instrument that will launch to the International Space Station to measure sunlight reflected from Earth. It will help us understand how much heat is being trapped by our planetâs atmosphere. Her mission is designed to help us get a clearer picture than we currently have of the Earthâs system and how it is changing
Yolanda took time from studying our home planet to answer questions about her life and career! Get to know this Earth scientist:
Starting in early middle school I became interested in the explanations behind the weather maps and satellite images shown on TV. I liked how the meteorologists talked about the temperature, moisture, and winds at different heights in the atmosphere, and then put that together to form the story of our weather forecasts. This made me want to learn more about Earth science, so I went to college to explore this interest more.
The summer after my junior year of college, I had an internship during which my first assignment was to work with a program that estimated ocean currents from satellite measurements. I was fascinated in the fact that scientists had discovered a way to map ocean currents from space!
Although I had learned about Earth remote sensing in my classes, this was my first taste of working with, and understanding the details of, how we could learn more about different aspects of the physical world from satellite measurements.
This led to my learning about other ways we can learn about Earth from space, and that includes rigorous climate monitoring, which is the area I work in now.
Before I start my workday, I like to take a few minutes to eat breakfast, knit (Iâm loving sock knitting right now!), and listen to a podcast or audio book. Each workday really looks different for me, but regardless, most days are a combination of quieter moments that I can use for individual work and more interactive times when Iâm interfacing with colleagues and talking about project or science issues. Both types of work are fun in different ways, but Iâm glad I have a mixture because all researchers need that combination of deep thinking to wrap our minds around complex problems and also time to tackle those problems with others and work on solving them together.
Iâve always loved sunsets. I find them peaceful and beautiful, and I love how each one is unique. They are also a beautiful reminder of the versatility of reflected light, which I study. Sitting for a moment to appreciate the beauty and calm I feel during a sunset helps me feel connected to Earth.
CLARREO Pathfinder (CPF) includes an instrument that will take measurements from the International Space Station and will measure reflected sunlight from Earth. One of its goals is to demonstrate that it can take measurements with high enough accuracy so that, if we have such measurements over long periods of time, like several decades, we could detect changes in Earthâs climate system. The CPF instrument will do this with higher accuracy than previous satellite instruments weâve designed, and these measurements can be used to improve the accuracy of other satellite instruments.
The longer I work in climate science and learn from the data about how humans have impacted our planet, the more I appreciate the fragility of our one and only home, and the more I want to take care of it.
Itâs ok to not have everything figured out at every step of your career journey. Work hard, do your best, and enjoy the journey as it unfolds. Youâll inevitably have some surprises along the way, and regardless of whether they are welcome or not, youâre guaranteed to learn something.
I see jigsaw puzzles as a good illustration of how different members of a science community play a diverse set of roles to work through different problems. Each member is often working on their own image within the greater puzzle, and although it might take them years of work to see their part of the picture come together, each image in the greater puzzle is essential to completing the whole thing. During my career, Iâll work on a section of the puzzle, and I hope to connect my section to others nearby, but we may not finish the whole puzzle. Thatâs ok, however, because weâll hand over the work that weâve accomplished to the next generation of scientists, and they will keep working to bring the picture to light. This is how I try to think about my role in climate science â I hope to contribute to the field in some way; the best thing about what I have done and what I will do, is that someone else will be able to build on my work and keep helping humanity come to a better understanding of our Earth system.
Time and project management skills â I think students tend to learn these skills more organically from their parents and teachers, but in my experience I stumbled along and learned these skills through trial and error. To successfully balance all the different projects that I support now, I have to be organized and disciplined, and I need to have clear plans mapped out, so I have some idea of whatâs coming and where my attention needs to be focused.
Another course not specifically related to my field is personal financial management. I was interested in personal finance, and that helped me to seek out information (mainly through various blogs) about how to be responsible with my home finances. There is a lot of information out there, but making sure that students have a solid foundation and know what questions to ask early on will set them to for success (and hopefully fewer mistakes) later on.
I think an interesting part of being an atmospheric scientist and a known sky-watcher is that I get to notice beautiful moments in the sky. I remember being on a trip with friends and I looked up (as I usually do), and I was gifted with a gorgeous sundog and halo arc. It was such a beautiful moment, and because I noticed it, my friends got to enjoy it too.
I absolutely loved being on the PBS Kids TV Show, SciGirls for their episode SkyGirls! This featured a NASA program called Studentsâ Clouds Observations On-Line (SâCOOL). It was a citizen science program where students from around the globe could take observations of clouds from the ground that coincided with satellite overpasses, and the intention was to help scientists validate (or check) the accuracy of the code they use to detect clouds from satellite measurements. I grew up watching educational programming from PBS, so it was an honor to be a science mentor on a TV show that I knew would reach children across the nation who might be interested in different STEM fields. In this photo, the three young women I worked with on the show and I are talking about the different types of clouds.
To stay up to date on Yolanda's mission and everything going on in NASA Earth science, be sure to follow NASA Earth on Twitter and Facebook.
đ If you're looking for Earth Day plans, we have live events, Q&As, scavenger hunts and more going on through April 24. Get the details and register for our events HERE.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
Matter makes up all the stuff we can see in the universe, from pencils to people to planets. But thereâs still a lot we donât understand about it! For example: How does matter work when itâs about to become a black hole? We canât learn anything about matter after it becomes a black hole, because itâs hidden behind the event horizon, the point of no return. So we turn to something we can study â the incredibly dense matter inside a neutron star, the leftover of an exploded massive star that wasnât quite big enough to turn into a black hole.
Our Neutron star Interior Composition Explorer, or NICER, is an X-ray telescope perched on the International Space Station. NICER was designed to study and measure the sizes and masses of neutron stars to help us learn more about what might be going on in their mysterious cores.
When a star many times the mass of our Sun runs out of fuel, it collapses under its own weight and then bursts into a supernova. Whatâs left behind depends on the starâs initial mass. Heavier stars (around 25 times the Sunâs mass or more) leave behind black holes. Lighter ones (between about eight and 25 times the Sunâs mass) leave behind neutron stars.
Neutron stars pack more mass than the Sun into a sphere about as wide as New York Cityâs Manhattan Island is long. Just one teaspoon of neutron star matter would weigh as much as Mount Everest, the highest mountain on Earth!
These objects have a lot of cool physics going on. They can spin faster than blender blades, and they have powerful magnetic fields. In fact, neutron stars are the strongest magnets in the universe! The magnetic fields can rip particles off the starâs surface and then smack them down on another part of the star. The constant bombardment creates hot spots at the magnetic poles. When the star rotates, the hot spots swing in and out of our view like the beams of a lighthouse.
Neutron stars are so dense that they warp nearby space-time, like a bowling ball resting on a trampoline. The warping effect is so strong that it can redirect light from the starâs far side into our view. This has the odd effect of making the star look bigger than it really is!
NICER uses all the cool physics happening on and around neutron stars to learn more about whatâs happening inside the star, where matter lingers on the threshold of becoming a black hole. (We should mention that NICER also studies black holes!)
Scientists think neutron stars are layered a bit like a golf ball. At the surface, thereâs a really thin (just a couple centimeters high) atmosphere of hydrogen or helium. In the outer core, atoms have broken down into their building blocks â protons, neutrons, and electrons â and the immense pressure has squished most of the protons and electrons together to form a sea of mostly neutrons.
But whatâs going on in the inner core? Physicists have lots of theories. In some traditional models, scientists suggested the stars were neutrons all the way down. Others proposed that neutrons break down into their own building blocks, called quarks. And then some suggest that those quarks could recombine to form new types of particles that arenât neutrons!
NICER is helping us figure things out by measuring the sizes and masses of neutron stars. Scientists use those numbers to calculate the starsâ density, which tells us how squeezable matter is!
Letâs say you have what scientists think of as a typical neutron star, one weighing about 1.4 times the Sunâs mass. If you measure the size of the star, and itâs big, then that might mean it contains more whole neutrons. If instead itâs small, then that might mean the neutrons have broken down into quarks. The tinier pieces can be packed together more tightly.
NICER has now measured the sizes of two neutron stars, called PSR J0030+0451 and PSR J0740+6620, or J0030 and J0740 for short.
J0030 is about 1.4 times the Sunâs mass and 16 miles across. (It also taught us that neutron star hot spots might not always be where we thought.) J0740 is about 2.1 times the Sunâs mass and is also about 16 miles across. So J0740 has about 50% more mass than J0030 but is about the same size! Which tells us that the matter in neutron stars is less squeezable than some scientists predicted. (Remember, some physicists suggest that the added mass would crush all the neutrons and make a smaller star.) And J0740âs mass and size together challenge models where the star is neutrons all the way down.
So whatâs in the heart of a neutron star? Weâre still not sure. Scientists will have to use NICERâs observations to develop new models, perhaps where the cores of neutron stars contain a mix of both neutrons and weirder matter, like quarks. Weâll have to keep measuring neutron stars to learn more!
Keep up with other exciting announcements about our universe by following NASA Universe on Twitter and Facebook.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
[click images for high quality]
[transcript under the cut]
Other advice posts that may be of interest:
How To Study When You Really Donât Want To
Active Revision Techniques
How To Do Uni Readings
How to Revise BIG Subjects
Keep reading
Black holes are some of the most bizarre and fascinating objects in the cosmos. Astronomers want to study lots of them, but thereâs one big problem â black holes are invisible! Since they donât emit any light, itâs pretty tough to find them lurking in the inky void of space. Fortunately there are a few different ways we can âseeâ black holes indirectly by watching how they affect their surroundings.
If youâve spent some time stargazing, you know what a calm, peaceful place our universe can be. But did you know that a monster is hiding right in the heart of our Milky Way galaxy? Astronomers noticed stars zipping superfast around something we canât see at the center of the galaxy, about 10 million miles per hour! The stars must be circling a supermassive black hole. No other object would have strong enough gravity to keep them from flying off into space.
Two astrophysicists won half of the Nobel Prize in Physics last year for revealing this dark secret. The black hole is truly monstrous, weighing about four million times as much as our Sun! And it seems our home galaxy is no exception â our Hubble Space Telescope has revealed that the hubs of most galaxies contain supermassive black holes.
Technology has advanced enough that weâve been able to spot one of these supermassive black holes in a nearby galaxy. In 2019, astronomers took the first-ever picture of a black hole in a galaxy called M87, which is about 55 million light-years away. They used an international network of radio telescopes called the Event Horizon Telescope.
In the image, we can see some light from hot gas surrounding a dark shape. While we still canât see the black hole itself, we can see the âshadowâ it casts on the bright backdrop.
Black holes can come in a smaller variety, too. When a massive star runs out of the fuel it uses to shine, it collapses in on itself. These lightweight or âstellar-massâ black holes are only about 5-20 times as massive as the Sun. Theyâre scattered throughout the galaxy in the same places where we find stars, since thatâs how they began their lives. Some of them started out with a companion star, and so far thatâs been our best clue to find them.
Some black holes steal material from their companion star. As the material falls onto the black hole, it gets superhot and lights up in X-rays. The first confirmed black hole astronomers discovered, called Cygnus X-1, was found this way.
If a star comes too close to a supermassive black hole, the effect is even more dramatic! Instead of just siphoning material from the star like a smaller black hole would do, a supermassive black hole will completely tear the star apart into a stream of gas. This is called a tidal disruption event.
But what if two companion stars both turn into black holes? They may eventually collide with each other to form a larger black hole, sending ripples through space-time â the fabric of the cosmos!
These ripples, called gravitational waves, travel across space at the speed of light. The waves that reach us are extremely weak because space-time is really stiff.
Three scientists received the 2017 Nobel Prize in Physics for using LIGO to observe gravitational waves that were sent out from colliding stellar-mass black holes. Though gravitational waves are hard to detect, they offer a way to find black holes without having to see any light.
Weâre teaming up with the European Space Agency for a mission called LISA, which stands for Laser Interferometer Space Antenna. When it launches in the 2030s, it will detect gravitational waves from merging supermassive black holes â a likely sign of colliding galaxies!
So we have a few ways to find black holes by seeing stuff thatâs close to them. But astronomers think there could be 100 million black holes roaming the galaxy solo. Fortunately, our Nancy Grace Roman Space Telescope will provide a way to âseeâ these isolated black holes, too.
Roman will find solitary black holes when they pass in front of more distant stars from our vantage point. The black holeâs gravity will warp the starlight in ways that reveal its presence. In some cases we can figure out a black holeâs mass and distance this way, and even estimate how fast itâs moving through the galaxy.
For more about black holes, check out these Tumblr posts!
â« Gobble Up These Black (Hole) Friday Deals!
â« Hubbleâs 5 Weirdest Black Hole Discoveries
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
Need study tips? Are you struggling to keep up in class? When you study you don't feel you learn much or anything at all? Getting better grades? Being more prepared than others?
Well. Me too.
So I did these things.
1- SING OUT LOUND! No, Wait! My brother does that. It's Read Out Loud
Be YOUR OWN TEACHER. Why? Good question, perhaps one of the reason can be MY TEACHER LEAVES THINGS OUT.
- Speaking the content out loud helps you to understand it better. Reciting out the words in YOUR OWN WORDS helps a lot. You learn aspects and even learn it far better than when you read a book. - When you speak the lesson or chapter out loud you are processing it as you speak. Think of it like you are giving a speech. Don't you want your speech to be as effective as possible? And how do you make it so effective? By getting authentic information of course!
Make flash notes. The best time to make them is as soon as a new chapter starts. If you are an Edexcel or Cambridge student, I'm sure you will understand just how important the specification is. Even the books has topics at the start of every chapter.
Use each point to make relevant notes on the specifications, this way you can easily know which main points of the topic if stated. Making these flash notes also help you revise and learn as you make them.
Let me know if you wish to know how to best make Flash Notes.
I will make sure to use an example and help you make them as well as link sites to help you better.
Hold it! Stop! Don't hit that back button just yet. This is annoying. So annoying but so desperately needed. You can't get good at Math with doing only one question a day. You need to practice, practice and practice. Study the concept, the method, relevant keywords. Know it so well you can dream of them and write them in your sleep. YOU NEED IT.
Math - those one-page questions need to be practiced at least 3-4 times until you learn it well enough. It seems like a lot of effort, and at times too much to handle and Math is like that but from a person with experience, doing just one question a day can take you up the ladder of improvement. Physics - questions need a to be revised and checked, especially those that voice out the same question. The question maybe same but they may have a different method of getting the answer. Chemistry - REVISE THE EQUATIONS. Think of the equations as the key aspect to breathing. One single thing wrong you lose a mark. AND EVERY MARK COUNTS. Biology - KEY TERMS. Key terms are so important, you have no idea. You cannot go in a Biology exam without those terms. At times the teachers won't even tell you those terms, So, those terms are so important you have no idea.
If you want to understand this better, do let me know. I will do my best to help you understand it better.
Once while doing a paper I was quite confident I would pass, until I got my paper back. Not only was my score low, but it was low due to certain answers not accepted by the paper. How come? They were the same points my teacher had told me about. Everything she taught, then why the low grade? Simple, because she never mentioned the answers that will be accepted in the paper. Some of the answers were never taught in class. Often times teachers do not mention certain points that are relevant to the papers and so students lose marks.
By attempting the papers, you understand what the examiner is looking for and how to best attempt the questions.
Tip: Pay attention to the reject part of the marking scheme. They help you understand the paper pattern and how best to assess the paper.
When you see that one question with at least 6-7 or 10-12 marks. NOTE THEM DOWN. Why? Simple they aid you when you need them most. Best example I have for you if the most recent one I did.
When studying for Chemistry Unit 5, those questions with even 5 marks that seem really important and you have not done in class before, have them in a note book. This lets you know what can and will come in the paper and how you must asset them.
Say that question where you must find the sides of the shape in Math. Trigonometry questions, find base from plane, those find the âXâ question and many more. If you cannot solve them or have trouble solving them and are taking a long time. NOTE THEM DOWN.
Have it in a notebook, with question and answer. Make it so when you come to revise later you can understand and figure out a way to gain those marks more easily.
I hope all this helps.
Here is a masterpost of MOOCs (massive open online courses) that are available, archived, or starting soon. I think they will help those that like to learn with a teacher or with videos. Â You can always check the audit course or no certificate option so that you can learn for free.
ASL University
Sign Language Structure, Learning, and Change
Arabic Without Walls
Madinah Arabic
Moroccan Arabic
Depi Hayk
Learn Bangla (Register to see course)
Parla.Cat
Speak Cat
Beginner
Chinese for Beginners
Chinese Characters for Beginners
Chinese for HSK 1
Chinese for HSK 2
Chinese for HSK 3 I & II
Chinese for HSK 4
Chinese for HSK 5
Mandarin Chinese Level I
Mandarin Chinese Essentials
Mandarin Chinese for Business
More Chinese for Beginners
Start Talking Mandarin Chinese
UT Gateway to Chinese
Intermediate
Intermediate Business Chinese
Intermediate Chinese Grammar
Mandarin for Intermediate Learners I
Introduction to Dutch
Online Courses here
Resources Here
Faroese Course
A Taste of Finnish
Beginner
AP French Language and Culture
Elementary French IÂ &Â II
Français Interactif
Vivre en France - A1
Vivre en France- A2
Intermediate & Advanced
French Intermediate course B1-B2
Passe-Partout
Travailler en France A2-B1 Â Â Â Â Â Â Â Â Â Â
Vivre en France - B1 Â
Beginner
Deutsch im Blick
German Project
German at Work
Goethe Institute
Introduction to Gwichâin Language
Biblical Hebrew
UT Austin
A Door into Hindi
Virtual Hindi
Icelandic 1-5
Learn Indonesian
Irish 101, 102, 103, 104, 105, 106, 107
Beginner
Beginnerâs Italian I
Introduction to Italian
Intermediate & Advanced
AP Italian Language and Culture
Intermediate Italian I
Advanced Italian I
Genki
Japanese JOSHU
Japanese Pronunciation
Marugoto Courses
Tufs JpLang
Beginner
First Step Korean
How to Study Korean
Introduction to Korean
Learn to Speak Korean
Pathway to Spoken Korean
Intermediate
Intermediate Korean
Introduction to Norwegian I, Norwegian II
Norwegian on the Web
Easy Persian
PersianDee
Online Course
Pluralidades em PortuguĂȘs Brasileiro
Beginner
A1 Course
I speak Russian
Intermediate
B1 Course
B1+ Course
B2.1 Course
B2.2 Course
Beginner
AP Spanish Language & Culture
Basic Spanish I, Spanish II
Spanish for beginners Â
Spanish for Beginners 1, 2, 3, 4, 5, 6
Spanish Vocabulary
Advanced
CorrecciĂłn, Estilo y VariacionesÂ
Leer a Macondo
Online Course
Online Course
Read Ukrainian
Speak Ukrainian
Beginnerâs Welsh
Discovering Wales
YorĂčbĂĄ YĂ© Mi
Ancient Languages
More Language Learning Resources & Websites!
Last updated: May 2019
It is that time of year againâŠTournament Earth is back! This year, NASA Earth Observatory has chosen a new theme for the tournament: astronaut photography. Choose your favorite image here.
For more than 20 years, astronauts have been shooting photos of Earth from the International Space Station that highlight the planetâs beauty, complexity, and vulnerabilities. So which are the most unforgettable ones? Over the next five weeks (March 8-April 13), you can help decide.
How can you get involved? Itâs easy as 1âŠ2âŠ3!
Not sure which image to vote for because they are ALL so captivating? Read the intriguing stories behind the images to help you decide! You can access the stories by clicking on the image headlines on the voting page: https://earthobservatory.nasa.gov/tournament-earth
For instance, the Stars in Motion image is actually a compilation of 72 photographs. And some of the night lights around Bangkok, Thailand, actually show fishing boats as well as city lights.
Think you know which photo will win it all? Fill out a #TournamentEarth bracket with your predictions and challenge friends! Then share your predictions with NASAEarth on our blog, Twitter, Facebook, Instagram, or right here on Tumblr!
We canât offer a trip to the Moon, but bragging rights are forever if you can pick the champion. Download a more print-friendly version of the bracket here.
Tournament Earth will have five rounds, and round one is currently underway. Voting for the following rounds begins on Tuesdays and will be open for six days. We will update our social media channels (including right here on Tumblr!) with the newest matchups. Check this space to see how your favorite images did. Then vote until we crown a champion on April 13, 2021.
See all of the images and vote HERE. Follow @NASAEarth on social media for updates.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com
âmoonwalkâ
This second, as youâre reading these words, trillions of tiny particles are hurtling toward you! No, you donât need to brace yourself. Theyâre passing through you right now. And now. And now. These particles are called neutrinos, and theyâre both everywhere in the cosmos and also extremely hard to find.
Neutrinos are fundamental particles, like electrons, so they canât be broken down into smaller parts. They also outnumber all the atoms in the universe. (Atoms are made up of electrons, protons, and neutrons. Protons and neutrons are made of quarks ⊠which maybe weâll talk about another time.) The only thing that outnumbers neutrinos are all the light waves left over from the birth of the universe!Â
Credit: Photo courtesy of the Pauli Archive, CERN
Physicist Wolfgang Pauli proposed the existence of the neutrino, nearly a century ago. Enrico Fermi coined the name, which means âlittle neutral oneâ in Italian, because these particles have no electrical charge and nearly no mass.
Despite how many there are, neutrinos are really hard to study. They travel at almost the speed of light and rarely interact with other matter. Out of the universeâs four forces, ghostly neutrinos are only affected by gravity and the weak force. The weak force is about 10,000 times weaker than the electromagnetic force, which affects electrically charged particles. Because neutrinos carry no charge, move almost as fast as light, and donât interact easily with other matter, they can escape some really bizarre and extreme places where even light might struggle getting out â like dying stars!
Through the weak force, neutrinos interact with other tiny fundamental particles: electrons, muons [mew-ons], and taus [rhymes with âowâ]. (These other particles are also really cool, but for right now, you just need to know that theyâre there.) Scientists actually never detect neutrinos directly. Instead they find signals from these other particles. So they named the three types, or flavors, of neutrinos after them.
Neutrinos are made up of each of these three flavors, but cycle between them as they travel. Imagine going to the store to buy rocky road ice cream, which is made of chocolate ice cream, nuts, and marshmallows. When you get home, you find that itâs suddenly mostly marshmallows. Then in your bowl itâs mostly nuts. But when you take a bite, itâs just chocolate! Thatâs a little bit like what happens to neutrinos as they zoom through the cosmos.
Credit: CERN
On Earth, neutrinos are produced when unstable atoms decay, which happens in the planetâs core and nuclear reactors. (The first-ever neutrino detection happened in a nuclear reactor in 1955!) Theyâre also created by particle accelerators and high-speed particle collisions in the atmosphere. (Also, interestingly, the potassium in a banana emits neutrinos â but no worries, bananas are perfectly safe to eat!)
Most of the neutrinos around Earth come from the Sun â about 65 billion every second for every square centimeter. These are produced in the Sunâs core where the immense pressure squeezes together hydrogen to produce helium. This process, called nuclear fusion, creates the energy that makes the Sun shine, as well as neutrinos.
The first neutrinos scientists detected from outside the Milky Way were from SN 1987A, a supernova that occurred only 168,000 light-years away in a neighboring galaxy called the Large Magellanic Cloud. (That makes it one of the closest supernovae scientists have observed.) The light from this explosion reached us in 1987, so it was the first supernova modern astronomers were able to study in detail. The neutrinos actually arrived a few hours before the light from the explosion because of the forces we talked about earlier. The particles escape the starâs core before any of the other effects of the collapse ripple to the surface. Then they travel in pretty much a straight line â all because they donât interact with other matter very much.
Credit: Martin Wolf, IceCube/NSF
How do we detect particles that are so tiny and fast â especially when they rarely interact with other matter? Well, the National Science Foundation decided to bury a bunch of detectors in a cubic kilometer of Antarctic ice to create the IceCube Neutrino Observatory. The neutrinos interact with other particles in the ice through the weak force and turn into muons, electrons, and taus. The new particles gain the neutrinosâ speed and actually travel faster than light in the ice, which produces a particular kind of radiation IceCube can detect. (Although they would still be slower than light in the vacuum of space.)
In 2013, IceCube first detected high-energy neutrinos, which have energies up to 1,000 times greater than those produced by Earthâs most powerful particle collider. But scientists were puzzled about where exactly these particles came from. Then, in 2017, IceCube detected a high-energy neutrino from a monster black hole powering a high-speed particle jet at a galaxyâs center billions of light-years away. It was accompanied by a flash of gamma rays, the highest energy form of light.
But particle jets arenât the only place we can find these particles. Scientists recently announced that another high-energy neutrino came from a black hole shredding an unlucky star that strayed too close. The event didnât produce the neutrino when or how scientists expected, though, so theyâve still got a lot to learn about these mysterious particles!
Keep up with other exciting announcements about our universe by following NASA Universe on Twitter and Facebook.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
sillygirlcarmen Friday Feels â12:22âł 15 minute mix
follow on instagram @sillygirlcarmen
Nicolas Geiser - Almost, 2015, stylo sur papier, 29,7 x 21 cm
https://www.pinterest.dk/jafersondoctar/
sillygirlcarmen Friday Feels â12:22âł 15 minute mix
follow on instagram @sillygirlcarmen
https://www.pinterest.dk/jafersondoctar/
TilfÞj mig pÄ Snapchat! Brugernavn: jaferson https://www.snapchat.com/add/jaferson