Astronomy

Does the sun have a protective shield

Does the sun have a protective shield


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Does the sun have a protective layer that at least diminishes its radiation. I know the earth's atmosphere protects us from harmful rays. But does the sun have a sort of shield as well that if removed would radiate more heat.


You seriously cannot expect the sun to have a layer that would contain some of its harmful radiation. Sun consists of a plasma and is not solid. Learn more about its structure here. Magnetic field is a kind of layer you might think of apart from all gases and energy it radiates. But that is harmful and not protective for us. It is highly unlike earth which has a solid crust. Any layer around sun wouldn't actually protect us as it would have to contain a huge amount of energy and that would make it more unstable.

Earth just happens to be at the right distance from the sun that was conducive enough to harbor a suitable atmosphere with just the right combination of the right elements and compounds (especially oxygen for breathing, ozone for protection and nitrogen for maintaining atmospheric balance). This is why life has been possible here. Earth also happens to have a magnetic field strong enough to protect us from the solar wind, as described in details here. It just diverts the harmful energy away from us. Containment of huge amount of energy is the major concern here and nobody is doing that.

So life has been possible only because the way earth has been created, well of course all energy comes from the sun. But the sun just provides energy and doesn't save us from itself.


Astronomy, Space Travel, and Our Coming Hurdles

These articles are a vast collection of my findings and interests regarding our colossal universe, ranging from abstract astronomical concepts to pure theory and ideas all made easy t understand for regular people like us! I hate searching for the things I want to know, so I wrote all of my findings here for you to enjoy with me. Supergiants, Nebulae, Magnetars, pulsars, black holes, space and time, gravity, speed of light travel, and the list goes on


Sunscreen Safety

There’s a lot of information out there about sunscreen safety, and not all of it is reliable. We asked a top expert, Elizabeth Buzney, MD, outpatient clinical director of the Department of Dermatology at Brigham and Women’s Hospital and assistant professor of dermatology at Harvard Medical School, to address some common questions about sunscreens. She also serves on The Skin Cancer Foundation’s Photobiology Committee.

Q: As a dermatologist and photobiologist, you’re an expert on the effects of sunlight on skin as well as sun protection and how it works. When some people say they’re concerned about the safety of sunscreens, how can we put that into perspective?

Dr. Buzney: For starters, we know that the sun causes most skin cancers. That is absolutely proven. We also know that in some cases, skin cancer can be deadly. We can talk about the alleged risks of sunscreens all you want, but the truth is that they help protect you from the potentially deadly risks from the sun.

We have also proven that sunscreen helps prevent skin cancer. Two important Australian studies showed that melanoma was reduced by 50 percent and squamous cell carcinoma by 40 percent in those who used sunscreen daily. That’s huge. So keep slathering on the sunscreen!

That said, I want to stress that when you think about sun protection, sunscreen is important, but you should also think beyond sunscreen. The safest and most effective method, used throughout history, is to minimize your exposure to the sun and wear clothing and hats. Any discussion of sun protection has to start with those.

Q: How do you respond when people say they worry about chemicals in their sunscreen?

Dr. Buzney: They may not think about it this way, but all sunscreen ingredients are chemicals. A molecule is a chemical. Even the “physical” sunscreens containing zinc and titanium are chemicals. Of course, there are different kinds of chemicals, and they can act in different ways. A more accurate classification system for sunscreen ingredients would be “organic” and “inorganic.” Organic ingredients are carbon-based molecules, such as avobenzone and oxybenzone. Inorganic ingredients are the minerals zinc oxide and titanium dioxide.

Q: Which types of sunscreen are least likely to cause skin sensitivity?

Dr. Buzney: When you think about allergy or sensitivity to a sunscreen, don’t assume it’s because of the active ingredient. A true allergy to the active ingredients is quite rare. It’s far more common to experience sensitivity to the inactive ingredients in sunscreens. There are emulsifiers, preservatives, fragrances, plant extracts, antioxidants and other ingredients that can cause contact dermatitis, including “natural” ingredients. For example, poison ivy is natural!

Some products have many inactive ingredients, and it can be difficult to identify which one is causing the trouble. An allergic reaction typically takes three to five days to develop. I often counsel my patients who have a sunscreen sensitivity to use the inorganic sunscreens — those that contain zinc oxide and/or titanium dioxide, and with as few other ingredients as possible.

Q: Can you address the concerns some people have about certain ingredients in sunscreens?

Dr. Buzney: Attention has focused most on the ingredient oxybenzone and whether it is a hormone disruptor. One study showed uterine growth in rats. But if you look at that study, they fed the rats a huge amount of this chemical over the course of four days. To duplicate that amount in humans would take applying sunscreen all over the entire body every day for 70 years. It was not an accurate model for what a human would be exposed to.

We know that oxybenzone is absorbed into the body to some degree, and is excreted in urine and breast milk. We don’t know the implications of its use in women who are pregnant or breastfeeding, because that type of clinical study can’t be performed on this group. So, out of an abundance of caution, I suggest they use a zinc- or titanium-based sunscreen.

Other claims about sunscreen ingredients have been floating around on the internet but are not backed up by hard science. For example, you may have read that sunscreen containing vitamin A, or retinyl palmitate, can cause skin cancer, but there’s no data to support that. People who use those sunscreens, or any sunscreens, can still develop skin cancer, and the most likely cause is skin damage from sun exposure in earlier years. And protecting yourself now could prevent skin cancers in the future.


Contact lenses can help protect your eyes from UV light

Sunglasses protect the eyes from many of the UV rays that would otherwise pass into our eyes, but they don’t stop everything. That’s where UV protection contact lenses come in. These enhanced contact lenses do the same thing as standard contacts: they ensure clear vision. But they have an added benefit. They serve as another line of defense against the unwelcome invasion of UV light into the eye.

We want to spend as much time celebrating the warm summer sun as possible, but we never want to risk our health to do so. That’s why we need UV protection on our contact lenses. It helps mitigate risk while ensuring comfort. Our strategy is simple: prepare for the sunlight before frolicking across the sand and those UV rays won’t stand a chance.


Sun's protective 'bubble' is shrinking

The protective bubble around the sun that helps to shield the Earth from harmful interstellar radiation is shrinking and getting weaker, Nasa scientists have warned.

New data has revealed that the heliosphere, the protective shield of energy that surrounds our solar system, has weakened by 25 per cent over the past decade and is now at it lowest level since the space race began 50 years ago.

Scientists are baffled at what could be causing the barrier to shrink in this way and are to launch mission to study the heliosphere.

The Interstellar Boundary Explorer, or IBEX, will be launched from an aircraft on Sunday on a Pegasus rocket into an orbit 150,000 miles above the Earth where it will "listen" for the shock wave that forms as our solar system meets the interstellar radiation.

Dr Nathan Schwadron, co-investigator on the IBEX mission at Boston University, said: "The interstellar medium, which is part of the galaxy as a whole, is actually quite a harsh environment. There is a very high energy galactic radiation that is dangerous to living things.

"Around 90 per cent of the galactic cosmic radiation is deflected by our heliosphere, so the boundary protects us from this harsh galactic environment."

The heliosphere is created by the solar wind, a combination of electrically charged particles and magnetic fields that emanate a more than a million miles an hour from the sun, meet the intergalactic gas that fills the gaps in space between solar systems.

At the boundary where they meet a shock wave is formed that deflects interstellar radiation around the solar system as it travels through the galaxy.

The scientists hope the IBEX mission will allow them to gain a better understanding of what happens at this boundary and help them predict what protection it will offer in the future.

Without the heliosphere the harmful intergalactic cosmic radiation would make life on Earth almost impossible by destroying DNA and making the climate uninhabitable.

Measurements made by the Ulysses deep space probe, which was launched in 1990 to orbit the sun, have shown that the pressure created inside the heliosphere by the solar wind has been decreasing.

Dr David McComas, principal investigator on the IBEX mission, said: "It is a fascinating interaction that our sun has with the galaxy surrounding us. This million mile an hour wind inflates this protective bubble that keeps us safe from intergalactic cosmic rays.

"With less pressure on the inside, the interaction at the boundaries becomes weaker and the heliosphere as a whole gets smaller."

If the heliosphere continues to weaken, scientists fear that the amount of cosmic radiation reaching the inner parts of our solar system, including Earth, will increase.

This could result in growing levels of disruption to electrical equipment, damage satellites and potentially even harm life on Earth.

But Dr McComas added that it was still unclear exactly what would happen if the heliosphere continued to weaken or what even what the timescale for changes in the heliosphere are.

He said: “There is no imminent danger, but it is hard to know what the future holds. Certainly if the solar wind pressure was to continue to go down and the heliosphere were to almost evaporate then we would be in this sea of galactic cosmic rays. That could have some large effects.

“It is likely that there are natural variations in solar wind pressure and over time it will either stabilise or start going back up.”


The sun has begun a new solar weather cycle. It should be pretty quiet, scientists say.

The sun is officially nine months into a new solar weather cycle, scientists have confirmed, and it will likely look much like its predecessor, which ran from 2008 to 2019.

Scientists predict that the sun's new activity phase, called solar cycle 25, will peak in 2025 but will generally be a less active cycle, quite similar to solar cycle 24, which ended in December. The sun's weather, which follows an 11-year activity cycle, is a vital phenomenon to predict because its whims impact life on and around Earth, sometimes with devastating consequences.

"We are very excited to be here today to announce that solar cycle 25 has officially started," Lisa Upton, co-chair of the Solar Cycle 25 Prediction Panel and a solar physicist at Space Systems Research Corporation, a mission-support company based in Virginia, said during a NASA news conference today (Sept. 15) to discuss the findings.

Space weather trackers should expect the sun's activity to rise and fall in a pattern similar to that of the last 11 years, Doug Biesecker, a solar physicist at NOAA&rsquos Space Weather Prediction Center and co-chair of the prediction panel, said. "Solar cycle 25 will reach a peak sunspot number of 115 in July of 2025," noting that a particularly active solar cycle usually sees a peak sunspot number over 200.

But just because the new cycle will be relatively quiet doesn't mean we should write it off, scientists stressed.

Biesecker pointed to a massive flare the sun produced in 2012, a few years before last solar cycle's peak. "We're saying cycle 25 is going to be like cycle 24 in terms of sunspots," he said. "Cycle 24 managed to produce an epic, hundred-year kind of solar storm, but it missed the Earth."

And even right now, when solar activity is still quite low, we can still feel the effects of our sun, the scientists said.

"During solar minimum, solar activity does not finish, it just changes form," Lika Guhathakurta, a heliophysicist at NASA's headquarters, said during the news conference. "For example, galactic cosmic rays are at an all-time high in the space environment, and this has all kinds of implications for space exploration, space tourism, and the aviation industry."

Another potential impact of a quieter sun is on space junk, which more active solar cycles can send into Earth's atmosphere to burn up. "A small solar cycle unfortunately means we're not going to be clearing out a lot of the orbital debris that a big solar cycle would take care of," Biesecker said.

In order to monitor and predict solar activity, scientists rely on a broad range of observations. Sunspot counts are the most straightforward — the more sunspots the more active the sun. How far north or south on the sun the earliest spots in a cycle begin to form can also give scientists a sense of what a season will be like, and right now, the sunspots that are popping up are closer to the equator, as is typical for quieter solar cycles.

Although the past few years have seen a host of new solar and space weather missions launch, Biesecker said that the prediction team didn't rely on data from those new spacecraft. "When we're trying to predict something that's got an 11-year cycle, new data is always useful, but it's hard to trust," he said. "So in general, the newer missions have not yet played a role in the process of predicting the cycle but that doesn't mean that they won't play a role in when we come around to trying to predict solar cycle 26."

Monitoring solar activity and making reliable predictions about upcoming solar cycles will be particularly important as astronauts once again venture out beyond the protection of Earth's magnetic field.

As part of its Artemis program, NASA is working to send astronauts back to the moon in the coming years, with humans stepping foot on the moon for the first time in five decades in 2024, the year before the solar cycle's predicted peak. That means that NASA needs good enough information about the sun's activity to feel confident it isn't sending astronauts into a dangerous situation.

To that end, the agency is also incorporating space-weather monitoring into its lead-up Artemis work, Jake Bleacher, chief exploration scientist for NASA Human Exploration and Operations Mission Directorate, said during the news conference, referencing plans to put solar weather instruments on the Gateway, NASA's planned outpost in lunar orbit that will support crew visits to the moon..

"The Gateway will be in place well before our astronauts are getting to the moon, so we'll have time to make some measurements and conduct some research there," Bleacher said. "We're trying to help add to the fleet of spacecraft that are measuring the sun and understanding this environment."


Jupiter: Our Cosmic Protector?

An object, probably a comet that nobody saw coming, plowed into the giant planet’s colorful cloud tops sometime Sunday, splashing up debris and leaving a black eye the size of the Pacific Ocean. This was the second time in 15 years that this had happened. The whole world was watching when Comet Shoemaker-Levy 9 fell apart and its pieces crashed into Jupiter in 1994, leaving Earth-size marks that persisted up to a year.

That’s Jupiter doing its cosmic job, astronomers like to say. Better it than us. Part of what makes the Earth such a nice place to live, the story goes, is that Jupiter’s overbearing gravity acts as a gravitational shield deflecting incoming space junk, mainly comets, away from the inner solar system where it could do for us what an asteroid apparently did for the dinosaurs 65 million years ago. Indeed, astronomers look for similar configurations — a giant outer planet with room for smaller planets in closer to the home stars — in other planetary systems as an indication of their hospitableness to life.

Anthony Wesley, the Australian amateur astronomer who first noticed the mark on Jupiter and sounded the alarm on Sunday, paid homage to that notion when he told The Sydney Morning Herald, “If anything like that had hit the Earth it would have been curtains for us, so we can feel very happy that Jupiter is doing its vacuum-cleaner job and hoovering up all these large pieces before they come for us.”

But is this warm and fuzzy image of the King of Planets as father-protector really true?

“I really question this idea,” said Brian G. Marsden of the Harvard-Smithsonian Center for Astrophysics, referring to Jupiter as our guardian planet. As the former director of the International Astronomical Union’s Central Bureau for Astronomical Telegrams, he has spent his career keeping track of wayward objects, particularly comets, in the solar system.

Jupiter is just as much a menace as a savior, he said. The big planet throws a lot of comets out of the solar system, but it also throws them in.

Take, for example, Comet Lexell, named after the Swedish astronomer Anders Lexell. In 1770 it whizzed only a million miles from the Earth, missing us by a cosmic whisker, Dr. Marsden said. That comet had come streaking in from the outer solar system three years earlier and passed close to Jupiter, which diverted it into a new orbit and straight toward Earth.

The comet made two passes around the Sun and in 1779 again passed very close to Jupiter, which then threw it back out of the solar system.

“It was as if Jupiter aimed at us and missed,” said Dr. Marsden, who complained that the comet would never have come anywhere near the Earth if Jupiter hadn’t thrown it at us in the first place.

Hal Levison, an astronomer at the Southwest Research Institute, in Boulder, Colo., who studies the evolution of the solar system, said that whether Jupiter was menace or protector depended on where the comets came from. Lexell, like Shoemaker Levy 9 and probably the truck that just hit Jupiter, most likely came from an icy zone of debris known as the Kuiper Belt, which lies just outside the orbit of Neptune, he explained. Jupiter probably does increase our exposure to those comets, he said.

But Jupiter helps protect us, he said, from an even more dangerous band of comets coming from the so-called Oort Cloud, a vast spherical deep-freeze surrounding the solar system as far as a light-year from the Sun. Every once in a while, in response to gravitational nudges from a passing star or gas cloud, a comet is unleashed from storage and comes crashing inward.

Jupiter’s benign influence here comes in two forms. The cloud was initially populated in the early days of the solar system by the gravity of Uranus and Neptune sweeping up debris and flinging it outward, but Jupiter and Saturn are so strong, Dr. Levison said, that, first of all, they threw a lot of the junk out of the solar system altogether, lessening the size of this cosmic arsenal. Second, Jupiter deflects some of the comets that get dislodged and fall back in, Dr. Levison said.

“It’s a double anti-whammy,” he said.

Asteroids pose the greatest danger of all to Earth, however, astronomers say, and here Jupiter’s influence is hardly assuring. Mostly asteroids live peacefully in the asteroid belt between Mars and Jupiter, whose gravity, so the standard story goes, keeps them too stirred to coalesce into a planet but can cause them to collide and rebound in the direction of Earth.

That’s what happened, Greg Laughlin of the University of California at Santa Cruz, said, to a chunk of iron and nickel about 50 yards across roughly 10 million to 100 million years ago. The result is a hole in the desert almost a mile wide and 500 feet deep in northern Arizona, called Barringer Crater. A gift, perhaps, from our friend and lord, Jupiter.


In a first, new 3D map reveals details about the edge of our solar system

Ever thought about what lies at the edge of our very own solar system? Turns out, it’s a blob (and a lot more)!

The universe holds secrets we’re not completely programmed to understand. But humanity is always at the cusp of a breakthrough when it comes to knowledge accumulation and the new 3D map of our solar system proves just that!

Ever thought about what lies at the edge of our very own solar system? Turns out, it’s a blob!

What's the edge of our solar system?

The edge of our system is where cosmic forces collide. On one edge lies solar wind comprising charged particles that emanate from the Sun. On the other side lie winds of space, laden with radiation absorbed from billions of stars situated nearby.

Solar winds or flares cause blackouts on Earth every once in a while but otherwise do an excellent job of protecting the planet from space radiation.

According to LiveScience, the solar winds wrap our solar system in a protective layer, preventing 70 per cent of space radiation from entering our system. Earth’s own magnetic shield does the job of protecting us from the leftover radiation.

This protective layer is called the heliosphere and its edge is called heliopause. At this junction lies a physical border where our solar system ends and the outside space begins.

What does the 3D map reveal?

On June 10, a new study in the Astrophysical Journal revealed the first 3D map of the heliosphere ever.

To achieve this, scientists used data collected by NASA’s Interstellar Boundary Explorer satellite over 10 years. Using this, they tracked particles in solar winds that travel from the Sun to the edge of solar system and back.

Based on this, they calculated how far the solar wind was able to go before being blown back by interstellar radiation. This allowed the researchers to map the edges of our solar system.

The map shows how the heliosphere isn’t really a sphere, but a squishy looking blob-like entity with inconsistent borders. In one end the border is thick while it is extremely thin on the other side.

This is because the Sun is also locked in orbit at the centre of the Milky Way, akin to Earth’s orbit around Sun. In one direction, the Sun has more scope of pushing out solar winds that counter interstellar radiation, explaining the inconsistency of the border.


17 Best Sunscreens for 2021 for Every Single Skin Type

If you're not wearing sunscreen all day, every day, then who even are you? Possibly my enemy, because come on protect yourself&mdashit's 2021, people! Skin cancer and premature aging are very real things, and it's officially time for you to do some intense adulting and sun-proof your face. But if you're not absolutely sure which SPF to choose, especially if you hate the feeling of sunscreens, or have oily skin, or dry skin, or sweat a lot, or whatever other excuse you can think of, then today is your lucky day. Because I rounded up the 17 best new sunscreens of 2021 that are so good, you'll forget you're wearing any at all.

Part moisturizer, part highlighter, part SPF&mdashSupergoop's Glowscreen Body is about to be your new go-to for spring and summer. Rub it into your body after you hop out of the shower or before you head out in the morning for skin that's smooth, has a subtle amount of shimmer, and stays protected from UV rays.

If you're curious about making the switch to an all-natural face sunscreen this year, I suggest trying this one from Grown Alchemist ASAP. It's vegan, reef-safe, made with plant-based ingredients (like castor seed oil and rosehip oil), and has 19.5 percent zinc oxide to prevent sunburn and sun damage.


Sun protection in Japan

Japanese women are famous for their beautiful skin. Not only do they seem to stay wrinkle free a lot longer than Western women, many of them also appear to have a perfectly even skin with a beautiful glow about it.

Japanese beauty expert Chizu Saeki, author of the book ‘The Japanese skin care revolution’, age 66 – Image from blogs.reuters.com

How do Japanese women achieve such beautiful skin? Apart from paying a lot of attention to skin care, and possibly genetic factors, I think the main reason is that Japanese women stay out of the sun. They do this not only to keep their skin young, they also want to keep their skin as white as possible. While in Belgium many women prefer ‘a healthy sun-kissed glow’, in Japan the beauty ideal is for skin to be as white as possible and free of any blemishes.

Japanese women take staying out of the sun to a whole other level. While most Western women (or should I just speak for myself?) already feel quite proud of themselves if they remember to put on some sun screen before leaving the house in the morning, Japanese women use many different attributes to avoid the sun.

Of course there is the age-old classic, the parasol or umbrella. It is really very common to see people in Japan using a parasol to shield themselves from the sun. Department stores play into this by selling beautiful summer parasols. I have to admit that even I have taken to the habit of using a parasol in summer in Japan. My main motivation is not so much skin care (I think the damage is already done there) but avoiding heat stroke. The summer sun in Japan is very intense. It took me a little while to overcome my culturally based embarrassment since people in Belgium would probably laugh at anyone using a parasol. After getting used to it however, I found it very convenient.

Mid July in Inuyama. The sun is beating down on the pavement and as you can see from the empty street, anyone in their right mind has sought refuge inside. Only two gaijin wander the afternoon streets. It is so hot that a sunshade seems required even while standing in the shade ^_^

A second popular attribute is the summer hat. In Belgium, only the most hardcore fashionistas will be seen wearing a summer hat. In Japan however, hats are very popular. There is a vast range of beautiful summer hats available. Some women, mostly elderly ladies, will even wear special hats with neck and throat covers.

Queuing to enter Nagoya Castle Festival in August. Sunshades and summer hats in abundance.

Some women go even further. They insist on keeping all body parts covered at all times, despite the smouldering summer heat of 35° C and over. This results in wearing tights and long-sleeved tops in summer. For women who still want to wear a short sleeve top but protect their skin at the same time, special arm and hand covers exist that can be slipped on when going outside or when driving a car.

Protective arm covers for sale A stylish Japanese lady with elaborate sun protection, consisting of a parasol, long gloves and nylons that were probably marketed as offering extra UV protection – Photograph by Martin Goodwin

Even women who work the land do their best to keep their skin as fair as possible. They will always wear gloves and a special hat that covers their face and neck as much as possible.

Farmer woman working the land in Japan – Image by Aaron Whitfield

The final attribute, and the one that surprised me the most, are special hand covers to be used when riding the bike. The covers are attached to the steering wheel and cover the hands completely.

A bicycle with protective sleeves for the hands

Now that I am living in Belgium again, I have eased up a bit on the sun discipline. After a long, dark Belgian winter, Belgian people tend to soak up as much sun as they can get during the summer. But the Japanese attitude towards the sun did have a lasting impact on me. I have gone from being an avid ‘sun worshipper’ to a careful recreational user.


Watch the video: HNOMS Skjold and Skudd (May 2022).