If you've visited an island like one in all the Hawaiian Islands, Tahiti, or Easter Island, also referred to as Rapa Nui, you will have noticed how small these landmasses appear in comparison with the vast Pacific Ocean. If you’re in Hawaii, the closest island is greater than 1,000 miles away and the coast of the continental United States is greater than 2,000 miles away. To say these islands are distant is an understatement.

For me: watching the film “Moana“2016 was eye-opening. I knew that Polynesians traveled between several Pacific islands, but watching Moana got down to sea on a canoe made me realize how small these boats are in comparison with a seemingly infinite ocean. But our fictional heroine launched into this journey anyway, just like the countless real-life Polynesian travelers on whom she is predicated.

As an astronomerFor greater than 20 years, I actually have been teaching students and visitors to our planetarium how you can find stars in our sky. As a part of instilling an appreciation for the great thing about the sky and stars, I need people to grasp that if you happen to know the celebs well, you possibly can never wander off.

U.S. Navy veterans learned concerning the stars of their navigation courses, and European cultures used the celebs for navigation, however the Polynesian wayfinding techniques shown in Moana brought these ideas to a really wide audience.

The movie Moana gave me a brand new approach – pun not intended – to my planetarium shows and lessons on finding objects within the night sky. With “Moana 2“I’m looking forward to seeing more astronomy on the big screen and exploring how I can build new lessons using the film’s ideas.”

The North Star

Have you ever found the North Star Polaris in your sky? I attempt to discover it each time I'm out and teach people attending my shows how you can use it “Pointer stars” within the bowl of the Big Dipper to seek out it. These two stars within the Big Dipper point you on to Polaris.

When you take a look at the North Star, you realize you’re looking north. Polaris is special since it is almost directly above the Earth's North Poleand so anyone north of the equator can see it in the exact same place within the sky all 12 months round.

It is a vital star for navigation because measuring its height above your horizon tells you ways far north of the Earth's equator you’re. For the massive number of people that live near 40 degrees north of the equator, you will note Polaris about 40 degrees above your horizon.

If you reside in northern Canada, Polaris will appear higher in your sky, and if you happen to live closer to the equator, Polaris will appear closer to the horizon. However, the opposite stars and constellations come and go along with the seasons, so what you see within the sky opposite the North Star changes every month.

You can use all the celebs to navigate, but to accomplish that you’ll want to know where to seek out them every night of the 12 months and at every hour of the night. Therefore, navigating stars aside from Polaris is tougher to learn.

Maui's fishing hook

At the top of June, around 11 p.m., you may notice a brilliant red star if you happen to look directly opposite the North Star. This is the star Antaresand it’s the brightest star within the constellation Scorpius.

However, if you happen to're a “Moana” fan like me and the remaining of my family, you may know this group of stars by a special name – Maui's fishing hook.

If you're within the Northern Hemisphere, Scorpio may not appear completely above your horizon, but if you happen to're on a Polynesian island, it’s best to see your entire constellation rising within the southeast and reaching its highest point within the sky when it's right within the sky South is and setting is within the southwest.

Astronomers and navigators can measure latitude by the peak of stars, like Maui and Moana did within the movie using their hands as measuring tools.

The easiest method to do that is to learn the way high Polaris is above your horizon. If you possibly can't see it in any respect, it’s essential to be south of the equator, but if you happen to see Polaris 5 degrees (the width of three fingers at arm's length) or 10 degrees above your horizon (the width of your full fist's arm's length), you then are 5 degrees or 10 degrees north of the equator.

The other stars, just like the ones in Maui's Fishhook, appear to rise, set and reach their highest point in other places within the sky depending on where you’re on Earth.

Polynesian sailors memorized where these stars would seem within the skies of the assorted islands between which they sailed, and so by searching for these stars within the night sky they were capable of determine by which direction they need to sail and the way long they need to travel across the ocean.

These days, most individuals simply pull out their phone and use the built-in GPS as a guide. Since Moana has been in theaters, I've seen a totally different response to my planetarium conversations about using the celebs for navigation. By showing exactly how Polynesian sailors used the celebs to sail across the ocean, Moana helps even those of us who’ve never sailed at night understand the methods of celestial navigation.

The first Moana movie got here out when my son was three years old and he immediately liked the songs, story and scenery. There are numerous jokes about parents dreading having to observe their kids' favorite movie over and once again, but in my case, I also fell in love with the movie.

Since then, I would love to thank the storytellers who made this film for taking such care to accurately portray the astronomy of navigation. I also liked that they showed how Polynesian travelers used the celebs and other clues, similar to ocean currents, to sail across the vast Pacific Ocean and land safely on a really small island hundreds of miles from their home.

Why is your body not transparent? Animals like jellyfish, Zebrafish and a few Glass frogs have transparent bodies. But most mammals, including humans, should not transparent.

While the concept of ​​a transparent body could appear strange and even a little bit scary, it could actually be very helpful for doctors. If our bodies were transparent, doctors could easily see inside to diagnose diseases in organs just like the liver, spleen, and brain. They wouldn't need invasive procedures like biopsies or expensive equipment like CT scanners and MRIs.

I’m a materials scientistand my team and I are working on how latest materials can aid biomedicine. My colleagues and I wondered whether it was possible to make living tissue temporarily transparent to assist medical treatments and other applications.

We found that by dissolving certain dye molecules, including a food coloring commonly utilized in snacks called FD&C Yellow 5in water, we will change the way in which light travels through the water. We have used this phenomenon to make organic tissue – specifically the skinny skin of mice – transparent in our study, published in September 2024 in Science.

Refractive indices

Our bodies, like those of most mammals, should not transparent, mainly due to the way in which light interacts with our tissues. Normally, light travels in a straight line through the air. But when light hits the human body, it doesn't travel very far before it’s scattered. The light bounces off in several directions as an alternative of passing through us in a straight line. If light passed through us without scattering, our tissues could be transparent.

This spread This is because human tissue is made up of many alternative components, including water, fats and proteins. Each of those components slows down light otherwise, a property generally known as Refractive index.

For example, water has a refractive index of about 1.33while fats and proteins have a better refractive index of about 1.45 within the visible spectrumLight subsequently moves more slowly in lipids than in water.

The key to transparency of living tissue could be to cut back the differences within the propagation of sunshine through different parts of the tissue – especially between water, fats and proteins.

Kramers-Kronig relationships

A principle of physics generally known as Kramers-Kronig relationships explains how a cloth that absorbs more light of 1 color, for instance blue, changes the movement of sunshine of one other color, for instance red, through the fabric because of this increased absorption. Kramers-Kronig relations state that the colours of sunshine should not independent of one another, but are connected to one another.

FD&C Yellow 5 strongly absorbs blue light, which supplies it its characteristic orange-red color when dissolved in water. This happens since the blue a part of the sunshine is absorbed, leaving only the orange-red part visible. Due to Kramers-Kronig relationships, this absorption of blue light increases the refractive index of water for red light. The refractive index of water increases from 1.33 to match that of fats and proteins, which is about 1.45.

When the refractive indices match, red light isn’t any longer scattered as much. It moves in water in the identical way that it does in fats in tissue. The entire tissue subsequently appears as a single, uniform material. This process could make the tissue appear transparent, regardless that it is often opaque.

Making fabric transparent

My research team implemented this concept in an experiment using a scatter phantom, a cloth designed to mimic the opacity of human skin. When we added more FD&C Yellow 5 dye to the phantom, it became more orange-red, just as expected.

But something else happened. It became more transparent to red light. This increased transparency allowed us to see the grid pattern on the table beneath the phantom.

We then decided to check this concept on a bit of chicken breast from the supermarket. Unless it’s sliced ​​very thinly, chicken meat often looks opaque.

When we placed the chicken breast in an answer containing FD&C Yellow 5 dye, something amazing happened. It became more transparent, allowing us to obviously see a Stanford shield attached underneath.

Finally, we used this concept to make a mouse's skin optically transparent. We applied the dye FD&C Yellow 5 to different parts of the mouse's body. When we applied it to the mouse's scalp, we could see the blood vessels in its brain. When we applied it to the mouse's abdomen, we could see its intestines. When we applied it to the mouse's limbs, we could see its muscle fibers.

All that was required for this experiment was gently massaging a dye solution into the mouse's skin and a little bit patience.

This process is non-invasive because it doesn’t require tissue removal or surgery and the skin will return to its normal opacity when you rinse the colour off with water. Although it’s a captivating technique, we strongly advise against trying this yourself.

Although the usage of Yellow 5 is approved by the FDA, some people have raised concerns about its potential Health risksThese include allergic reactions – particularly in asthmatics – hyperactivity in children and possible links to cancer. But researchers must do more testing to find out if there are any dangers.

Future uses

So what could this approach be used for? Currently, it really works best on very thin layers of skin, like that of a mouse.

Unfortunately, human skin is far thicker, so this method will not be quite ready for practical use on humans. Additionally, the red color of the dye implies that the colour balance will not be quite right and the transparency will not be perfect across your complete surface. entire visible spectrumThe dye still blocks blue light.

My colleagues and I are working to enhance this method to make it more practical for human tissue. We are also attempting to direct the absorption of the dye towards the Ultraviolet spectrumwhich might create a more balanced transparency effect across all visible colours.

In the longer term, this technology could make veins more visible, making venipuncture – the practice of drawing blood or injecting fluids using a needle – easier, especially in older patients with difficult-to-see veins.

It could also help to Early detection of skin cancerexpand Light irradiation into deep tissue for photodynamic And Photothermal therapies and simplify Laser tattoo removal.

In photodynamic and photothermal therapies, doctors use a laser to kill cancer cells and precancerous lesions. However, the laser light only penetrates the tissue to a certain extent, so these therapies should not yet suitable for organs situated deeper within the body.

All of those applications may gain advantage from a reversible, on-demand transparency window within the body.