Scientists discover an on/off switch for sperm that could lead to better male contraceptives


Researchers have made a discovery that could lead to better birth control measures for both men and women: a biological on/off switch that controls the movement of sperm. As well as helping couples avoid unwanted pregnancies, the new findings could also help improve fertility rates for those struggling to conceive.

As Gizmodo reports, the protein at the centre of the new study is the little-known ABHD2. Experiments carried out by teams at UC Berkeley and Yale University show that this protein is required for the biological processes that cause sperm to become more energetic swimmers.

Ordinarily, the ova puts out a hormone called progesterone to encourage a sperm race, and the progesterone is triggered by the opening of a calcium channel called CatSper. And now it seems that ABHD2 sits between the progesterone and the CatSper in this biological chain of events.

This means that ABHD2 is essential in getting the progesterone to react with CatSper and cause the sperm tails to kick into a frenzy. Without that reaction, the sperm just drift along as normal.

It’s an important internal mechanism – after all, you don’t want sperm sprinting towards an egg prematurely and running out of energy before they get there. “This gives us an understanding of another pathway that is involved in human sperm activity,” said one of the team, Melissa Miller from UC Berkeley.

If ABHD2 can somehow be inhibited, it could pave the way for an effective contraceptive drug for both men and women.

“What’s really cool is that we have an actual target for unisex contraceptive development. If you can stop progesterone from inducing a power stroke, sperm are not going to be able to reach or penetrate the oocyte,” says Miller.

“People tend to think of fertilisation as like a marathon, where the fastest, most powerful sperm is going to win,” she added. “We think of it like the Tour de France, where the riders in front are blocking the wind for the actual winner. Fertilisation is a team sport, where the first sperm clear the way, expending their energy to break through the barrier cells, so that the slow and steady guy can get into the oocyte.”

The research has also cast new light on a long-standing mystery surrounding the performance of steroids like progesterone: specifically, why the reactions they produce can take days or happen instantly.

As scientists begin to understand more about steroid signalling in sperm, the team says, it could help inform research into many other types of cells too.

A weak magnetic field saved life on Earth


The early Solar System was a much different place than it is now.

Chaos reigned supreme before things settled down into their present state.

solar flare

New research shows that the young Sun was more chaotic and expressive than it is now, and that Earth’s magnetic field was key for the development of life on Earth.

Researchers at the Harvard Smithsonian Centre for Astrophysics have been studying a star called Kappa Ceti, about 30 light years away in the Cetus constellation.

Kappa Ceti is in many ways similar to our own Sun, but it’s estimated to be between 400 million to 600 million years old, about the same age as our Sun when life appeared on Earth.

Studying Kappa Ceti gives scientists a good idea of the type of star that early life on Earth had to contend with.

Kappa Ceti, at its young age, is much more magnetically active than our 4.6 billion year old Sun, according to this new research.

It emits a relentless solar wind, which the research team at Harvard says is 50 times as powerful as the solar wind from our Sun.

It’s surface is also much more active and chaotic. Rather than the sunspots that we can see on our Sun, Kappa Ceti displays numerous starspots, the larger brother of the sunspot.

And the starspots on Kappa Ceti are much more numerous than the sunspots observed on the Sun.

We’re familiar with the solar flares that come from the Sun periodically, but in the early life of the Sun, the flares were much more energetic too.

The early Solar System was a much different place than it is now.

Chaos reigned supreme before things settled down into their present state.

New research shows that the young Sun was more chaotic and expressive than it is now, and that Earth’s magnetic field was key for the development of life on Earth.

Researchers at the Harvard Smithsonian Centre for Astrophysics have been studying a star called Kappa Ceti, about 30 light years away in the Cetus constellation.

Kappa Ceti is in many ways similar to our own Sun, but it’s estimated to be between 400 million to 600 million years old, about the same age as our Sun when life appeared on Earth.

Studying Kappa Ceti gives scientists a good idea of the type of star that early life on Earth had to contend with.

Kappa Ceti, at its young age, is much more magnetically active than our 4.6 billion year old Sun, according to this new research.

It emits a relentless solar wind, which the research team at Harvard says is 50 times as powerful as the solar wind from our Sun.

It’s surface is also much more active and chaotic. Rather than the sunspots that we can see on our Sun, Kappa Ceti displays numerous starspots, the larger brother of the sunspot.

And the starspots on Kappa Ceti are much more numerous than the sunspots observed on the Sun.

We’re familiar with the solar flares that come from the Sun periodically, but in the early life of the Sun, the flares were much more energetic too.

Researchers have found evidence on Kappa Ceti of what are called super-flares. These monsters are similar to the flares we see today, but can release 10 to 100 million times more energy than the flares we can observe on our Sun today.

So if early life on Earth had to contend with such a noisy neighbor for a Sun, how did it cope? What prevented all that solar output from stripping away Earth’s atmosphere, and killing anything alive? Then, as now, the Earth’s electromagnetic field protected it.

But in the same way that the Sun was so different long ago, so was the Earth’s protective shield. It may have been weaker than it is now.

The researchers found that if the Earth’s magnetic field was indeed weaker, then the magnetosphere may have been only 34% to 48% as large as it is now.

The conclusion of the study says “…the early magnetic interaction between the stellar wind and the young Earth planetary magnetic field may well have prevented the volatile losses from the Earth exosphere and created conditions to support life.”

Or, in plain language: “The early Earth didn’t have as much protection as it does now, but it had enough,” says Do Nascimento.

Evidently.

Researchers have found evidence on Kappa Ceti of what are called super-flares. These monsters are similar to the flares we see today, but can release 10 to 100 million times more energy than the flares we can observe on our Sun today.

So if early life on Earth had to contend with such a noisy neighbor for a Sun, how did it cope? What prevented all that solar output from stripping away Earth’s atmosphere, and killing anything alive? Then, as now, the Earth’s electromagnetic field protected it.

But in the same way that the Sun was so different long ago, so was the Earth’s protective shield. It may have been weaker than it is now.

The researchers found that if the Earth’s magnetic field was indeed weaker, then the magnetosphere may have been only 34% to 48% as large as it is now.

The conclusion of the study says “…the early magnetic interaction between the stellar wind and the young Earth planetary magnetic field may well have prevented the volatile losses from the Earth exosphere and created conditions to support life.”

Or, in plain language: “The early Earth didn’t have as much protection as it does now, but it had enough,” says Do Nascimento.

Evidently.

Could Glowing ‘Bionic’ Plants be the Future of Street Lights?


Nanotechnology is the study and application of using miniscule particles (atoms, molecules, etc.) to manipulate matter. In the plant world, scientists have used this technology to create “bionic plants”, plants that are capable of absorbing more sunlight, and potentially making use of light wavelengths they don’t normally use. What this means for the future is anyone’s guess—stronger, bigger plants, and even plants as futuristic street lights.

report in Nature Materials reveals scientists wanted to see how they could insert nanotubes into the “brains” of plants, their chloroplasts, that turn sunlight and CO2 into energy. They found that by simply placing a dilution of carbon nanotubes on the underside of Arabidopsis thaliana leaves, the plant would absorb them in the same manner they absorb carbon dioxide.

These absorbed nanotubes made their way into the chloroplasts unassisted. Prepared in advance to give off a glow when photosynthesis occurs, the nanotubes caused the plant to changed colors. Analyzing the reaction in the plants, the scientists were able to determine an average 30 percent increase in energy in those who received the nanotubes.

bionicc p

The scientists also used the nanotechnology to detect pollutants in plants, using dilutions specifically targeted to light up in the presence of nitric oxide, a pollutant produced during combustion.

Finally, the researchers used another nanoparticle to help plants clear out free radicals, or pollutants that can damage DNA and essentially break down the survival mechanisms in plants. Treating plants with nanoceria, or nanoparticles of metallic cerium, the researchers found 27 percent fewer free radicals when compared with untreated plants.

“Plants are very attractive as a technology platform,” says Michael Strano, lead researcher. “They repair themselves, they’re environmentally stable outside, they survive in harsh environments, and they provide their own power source and water distribution.”

What does all of this research mean? The team hinted that manipulating the nanotechnology could lead to plants having mobile phone signaling power and even turn them into miniature street lamps, glowing in the dark. It also means that nanotechnology could be used to track plant pollution and help plants fight the effects of free radical damage.

Are You Type A Or Type B


http://www.buzzfeed.com/perpetua/are-you-type-a-or-type-b?bffbmain&utm_term=4ldqpgp#4ldqpgp

A Mysterious Disease Is Killing People in Wisconsin


SINCE NOVEMBER, 54 PEOPLE in Wisconsin have one by onefallen ill with an obscure kind of bacteria called Elizabethkingia. Fifteen have died from the infection.

Elizabethkingia is common in the environment—in soil, in water—but it rarely gets people sick. Cases pop up in ones and twos, usually in people with weak immune systems, says Michael Bell, deputy director of the Centers for Disease Control and Prevention’s healthcare quality division. “The fact that we’re seeing more than four dozen cases, that is a very large outbreak.” In fact, an outbreak of this size forElizabethkingia, named for the bacteriologist who first isolated it in the 1950s, is unprecedented. The bacteria infects the blood, causing fever, chills, and shortness of breath.

What’s going on? It’s a mystery for the CDC’s disease detectives, a corps of about 70 doctors and epidemiologists who specialize in tracing outbreaks, from foodborne illnesses to Ebola. Wisconsin’s public health department contacted the CDC for help in February, and the federal agency now have team of seven people on the ground in Wisconsin.

At first, the CDC suspected the tap water. Just this January, the CDC’s emerging diseases journal published a reportabout a nearly two-year long Elizabethkingia outbreak in a London critical care unit that ended up originating with contaminated taps in hospital sinks. But the tap water in Wisconsin turned up negative for the bacteria.

Adding to the mystery, this outbreak doesn’t match the pattern of other infections, which appeared in clusters in the same facility. Most of Wisconsin patients were elderly; some lived in nursing homes and others had gone to the hospital, but they lived across 12 different counties. At the same time, the genetic signature of the bacteria points to a single source. The infection seems, to use the language of epidemiology, to be community-acquired. This makes tracing a source more difficult: The CDC’s officials can’t just order up medical records from a single hospital and test the area exhaustively.

So the disease detectives have fanned out across the state, knocking on doors of patients. The CDC’s staff asks questions, filling in the blanks with samples of personal care products like lotions or wipes that might harbor the bacteria. The freshest cases take precedence. “With older cases,” says Bell, “you’re dealing with materials already discarded and memories already faded.”

The questions they ask are methodical and standardized. For example, if you want to ask if someone has eaten lettuce, “most people will just think of salad,” says Bell. So instead, the CDC might ask if you got lettuce or a sandwich with lettuce. “When you point it out, it can jog their memory. You make sure that everyone gets a consistent shake answering the questions,” says Bell. And like good scientists, they talk to a control group of people who live in the same communities but have not gotten sick. Then they start crossing off hypotheses. A 10 hour day on the road might end with several more hours of data entry.

At this point, CDC is still investigating water—though other sources like water used on produce, which requires tracing it back to grocery stores or farms. “The amount of potential exposure sources is very large,” Bell says.

The outbreak is still going on, but Bell sees some hope in the numbers. Elizabethkingia is resistant to some but not all antibiotics, and the number of deaths has held steady as doctors have learned how to treat the once-obscure bacteria. Wisconsin may be seeing a new bacterial threat, but at least the CDC is learning how to handle it.

The Art of Drinking Water: 25 Ayurvedic Tips for a Happily Hydrated Body


How much water should I drink?

For years, most of us have heard the suggestion that the best way to consume water is drink “8 cups of water a day.” Unfortunately it isn’t really that simple. In fact, each of us has a unique constitution and lifestyle that actually has different requirements to stay hydrated. The amount of re-hydration we need on a given day is directly related to how much hydration we have lost through the loss of bodily fluids.

When we eat, we need to sip just enough fluid with our meal to make our food somewhat liquid. In addition, if we can’t digest our water it doesn’t matter how much we drink, we never really get hydrated. It may seem strange to think that we have to digest our water but, just like anything that we swallow, water has to be digested and transformed into a suitable fluid for our body’s nutritional needs. We have probably all had the experience of feeling bloated and overly full after drinking water—this is a sign that it is not being properly transformed.

And that is actually the most important factor. Our body is not like a sponge. Our bodily tissues don’t just immediately soak up the water we drink and suddenly become hydrated. If we drink too much water, just as when we eat too much food, we can dampen our digestive fire. Drinking too little water can also weaken our digestion.

The simplest way to know how much water we should drink is to drink when we are thirsty. Modern nutritionists say this is probably too late, as we are already overly dehydrated by this point—but this may be because most of us have lost touch with the subtle signs of our thirst. It may take some time to redevelop that sensitivity.

n general, all of us will tend to need to drink more water from the middle of summer through the autumn and less from mid-winter through the spring.

When Should I Drink Water?

Again, the best rule of thumb is to drink when you are thirsty.

Drinking cold water (or any cold beverage) constricts the flow of blood to the digestive tract, making digestion more sluggish. By now many of us have heard that we shouldn’t drink beverages with our meal, but when we eat, we do need to sip just enough fluid with our meal to make our food somewhat liquid. This is why many cultures around the world include a small cup of tea or soup with every meal. In some cuisines, it is common to drink a bowl of broth before eating.
One way to start to get in touch with the sensation of thirst is to drink a glass of water large enough to quench your thirst when you wake up. Wait at least an hour before eating breakfast. Then again at least an hour before your next meal (at least 1.5-2 hours after eating) drink a glass of water. If you normally eat 3 meals a day, then repeat this before your next meal. The size of the glass of water should vary, based on what you want to drink at the moment.

Cooking Your Water

Cooking our food and drinks is a process of pre-digestion. This means that our body doesn’t have to work as hard to get benefit from our nourishment. In fact, it makes the nourishment more available to our body.

Using clear spring water or filtered water (tap water is also usually fine), boil it for 10 minutes. This water cooled to room temperature and kept in a covered container is said to be easy to digest and particularly good for soothing inflammatory (Pitta) conditions in the body.

Drinking the boiled water while it is still warm is even more medicinal. Hot water is said to stimulate hunger and aid digestion of food. It is good for the throat, easily digested, and cleanses the urinary bladder. In addition, it relieves hiccups, bloating and aggravation of Vata and Kapha doshas. It can be helpful in reducing fever and easing cough and asthma. It helps the body get rid of accumulated, undigested food and can soothe pain in the hips and back.

In contrast, drinking cold water (or any cold beverage) constricts the flow of blood to the digestive tract, making digestion more sluggish. This is made much worse when the cold beverage is taken with a meal.

Adding Oomph to Your Water

Sometimes it can be helpful to add some spices or herbs to water to make it more absorbable—and more interesting. This is essentially what we are doing when we make tea. Here are some spices that can make your water even more medicinal:

Cumin, coriander and fennel seeds

Add about 5 seeds of each for every ½ c. of water when you are boiling it. Strain out the seeds before drinking. This blend is particularly good for stimulating digestion during gentle cleanses.

Sandalwood, cardamom or mint

These cooling herbs can soothe Pitta irritability, especially during the hot summer months. A pinch of powder herb or a few leaves of mint will work nicely. If you are used to drinking hot mint tea, try just putting the mint into cooled water. It has a really nice cooling effect on a hot day!

Honey

Uncooked honey added to cooled water (about a ½ tsp. or so) can be a good aid to weight loss and helps to clear excess Kapha during the spring.

Ginger

A pinch of ginger powder in your morning glass of water enkindles your digestive fire and can be helpful for reducing Vata and Kapha excess.

Gold

Yes, gold. In this case, you are not really adding gold to your water, but just putting gold into the pot with the water when you boil it. It should be 22k or higher. I use a simple gold ring without any stones (gemstones have other effects that may be undesirable). Gold is said to greatly enhance immunity.

A New Material Could Make Medical Devices That Expand and Collapse


Harvard researchers develop a new origami-inspired material that changes shape

Shapeshifting material
Pneumatics allow the material to change shape.

Johannes Overvelde was pursuing a PhD in applied mathematics at Harvard University when he met Chuck Hoberman, designer of the Hoberman Sphere, a collapsible rainbow ball for kids. Both lived in Cambridge and had similar interests. Overvelde was working on developing transformable materials that could change stiffness, and Hoberman, an architect who also studies kinetic structures, had been thinking about how different materials could take on the properties of his sphere, changing form by articulating at different joints.

shapeshifting material.gif
The material in action. 

Borrowing bits from the Hoberman Sphere and the origami-based concept of snapology, where interlocking strips of paper snap together to create rigid structures, Overvelde and his team at Harvard have created what they call a metamaterial: an expandable structure that can be used on its own, or as a building block to create other structures. The attenuated cubes, which have three degrees of articulation, are made of thin polymer sheets that fold flat but can also pop up in a variety of different ways, just like the Hoberman Sphere. By attaching it to a pneumatic hose, a user can inflate a cube to create a bigger 3D structure. Overvelde says the material has numerous applications, from nano-scale stents that can be inserted into arteries and then expanded, to walls, which would fold open and ventilate your house when it gets hot.

“While snapology provides the geometric starting point for our research, our focus here is on the foldability of these structures and how this can lead to new designs for transformable metamaterials,” Overvelde writes in a new paper, published in Nature Communications.

The researchers started with paper models, trying to prove that, with snapology, they could build something solid enough to use in architecture.

“We had a paper model that was glued together, but this was a lot of work, and the paper model broke after a week,” Overvelde says. “So we thought, ‘can we bring this more to an engineered structure?’ Using double-sided tape and laser cut thin plastic sheets—one thicker for faces, and one thinner for hinges—we made these units that could be deployed completely flat, but had specific degrees of freedom we hadn’t seen before.”

From there, the team experimented with different ways to change the shape of the structure. They decided that pneumatic activation, which was precise and easy to incorporate by running air hoses through the cubes, would let them use a structure in the most ways possible. The shape changes depending on which part of the structure is filled with air. “Any structure we make with this device will be reconfigurable,” he says.

The cube can be compressed so that it lies flat.
The cube can be compressed so that it lies flat. 

For Overvelde, flexibility is the most important part of the concept. He likes to think of the cubes as a material, instead of just a structure unto themselves, because he thinks a lot of the value of the discovery comes from the many different ways they can be built.

The group’s initial test cube was 50 centimeters square. But the idea is scalable—they have built a folding chair. Now, the researchers are experimenting with making the inflation mechanism sensitive to ambient cues, such as light or moisture. On a very small scale, the cubes can act like photonic crystals, reflecting back different wavelengths of light and different colors as they change shape.

“If you have a wing of a butterfly, the structure gives it color. So if you had a device that wants to change color, you could mimic that,” Overvelde says. “On the other side, you think about architectural application. If you made it responsive to heat, you could make a wall of this structure that opens up and breathes. You could make a structure that responds to water, so when it rains, it automatically closes up.”

The technology could have lots of applications.
The technology could have lots of applications. 

Overvelde has proven that the concept works, and now he wants to see how it can be applied. In addition to photonic crystals and the moveable architecture, he thinks it could be used for everything from medical devices, that could be packed flat for easy insertion into the body, to robots and deployable spaceships.

“I’m really curious to see how other researchers will pick it up,” he says.

 

How much sleep do you actually need?


World Sleep Day 2016: How much sleep do you actually need?

Someone hit the snooze button – because it is World Sleep Day today.

While most of us constantly feel tired, whether hangover related or just down to working too damn hard, you might not need as much sleep as you might think.

That’s because often it’s the quality of your sleep rather than the hours you spend tucked up under the duvet.

How much sleep do you actually need?

Sleep times

Newborns (0-3 months ): Sleep range narrowed to 14-17 hours each day (previously it was 12-18)Infants (4-11 months): Sleep range widened two hours to 12-15 hours (previously it was 14-15)

Toddlers (1-2 years): Sleep range widened by one hour to 11-14 hours (previously it was 12-14)

Preschoolers (3-5): Sleep range widened by one hour to 10-13 hours (previously it was 11-13)

School age children (6-13): Sleep range widened by one hour to 9-11 hours (previously it was 10-11)

Teenagers (14-17): Sleep range widened by one hour to 8-10 hours (previously it was 8.5-9.5)

Younger adults (18-25): Sleep range is 7-9 hours (new age category)

Adults (26-64): Sleep range did not change and remains 7-9 hours

Older adults (65+): Sleep range is 7-8 hours (new age category)

The National Sleep Foundation (yep) suggests that the amount of sleep you need very much depends on your age.

Most young adults only need between seven and nine hours a night, but can get away with sleeping just six hours.

Teenager meanwhile need at least seven hours in bed, but can happily sleep for 11. School children are recommended to have between nine and 11 hours.

Older adults need five or six hours between the sheets but it is recommended they have between seven and eight.

Babies need a lot more sleep of course, lying in their cots for up to 19 hours a day.

Your sleep health is important

snuggling going to sleep

It’s all about getting quality sleep rather than just the hours in bed.

Stimulants like coffee, tea and energy drinks don’t help as they can interfere with people’s ‘circadian rhythm’, which is your natural sleep cycle.

The same is true for alarm clocks and poor lighting.

If you don’t get enough sleep each night, your body will begin to develop ‘sleep debt’ and you’ll feel exhausted, which can have an affect on your overall well-being and health.

Why do we need sleep?

When we are awake, a chemical called adenosine builds up in the bloodstream.

It is only when we are asleep that the body is able to break this chemical down and if you don’t get enough sleep your body won’t have enough time to break down the chemical.

The result is a slow down in your reactions, feeling generally tired and wanting to have a nap.

How to improve your sleep

11 things you should know, if you know someone who has panic attacks (Jo Irwin) Mmuffin---Metro

For those who aren’t getting enough hours in bed, it is all about setting a sleep schedule and sticking to it.

Sometimes that means heading to bed 15 minutes earlier, while other times it might mean adjusting electronics so they aren’t waking you up in the middle of the night.

If you are struggling to sleep, there are several factors that could be causing this – including poor diet, poor sleeping arrangements and even the temperature of your bedroom.

Ditch the alcohol and caffeine, and make sure you exercise daily.

Number of pregnant women with Zika infections increases


The Centers for Disease Control and Prevention is reporting nine additional Zika infections in pregnant women.

Eighteen cases of Zika have been diagnosed in pregnant U.S. women, up from the nine that the CDC has previously reported in detail.

Eight of the 18 women are still pregnant, while 10 have either delivered their babies or had abortions or miscarriages, according to the CDC.

All of the  women had traveled to an area with a Zika outbreak, according to the CDC. Zika virus is not yet spreading in the continental USA. At least 258 U.S. travelers have been infected with Zika while visiting the Caribbean or South America.

Zika is spreading widely in Puerto Rico and other U.S. territories, which are reporting three travel-related cases and 283 cases spread by local mosquitoes, including 35 in pregnant women. Zika is spread by the Aedes aegypti mosquito.

The CDC has started a pregnancy registry to learn more about Zika-affected cases.

The CDC has reported details for the first nine of the pregnancies: one woman gave birth to a baby with microcephaly, a condition in which babies are born with abnormally small heads and incomplete brain development; two miscarried; two had abortions; two gave birth to healthy babies and two are still pregnant.

The number of Zika-affected countries with microcephaly cases is growing.

Doctors have diagnosed microcephaly in Cape Verde, an island off the coast of Africa that has been battling a Zika virus epidemic.

Researchers are investigating the case to see if it’s related to Cape Verde’s Zika infection, according to the World Health Organization.

Brazil, which normally had about 150 cases of microcephaly a year, has confirmed 863 cases of the condition in recent months, said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. Brazil is investigating an additional 4,268 suspected cases of microcephaly. A handful of cases of microcephaly also have been diagnosed in Colombia, which also has a large Zika outbreak, he said.

There have been 7,490 suspected cases of Zika virus in Cape Verde between Oct. 21 and March 6, according to the WHO. About 165 of the cases involve pregnant women; 44 of these women have delivered without any complications or abnormalities.

In related news, the Food and Drug Administration issued an emergency approval for a new three-in-one test for Zika, dengue and chikungunya viruses, which are all spread by the Aedes mosquito. The CDC hopes the new test will save time, because doctors will be able to test for all three viruses at once, instead of running three separate tests. The test uses a polymerase chain reaction (PCR) technique to detect genetic material from the viruses in blood. Because the Zika virus only stays in the blood for about a week, the test will only produce positive results during that time.

The CDC will begin sending to 150 labs around the USA on Monday, and also send the tests to countries and territories with Zika outbreaks.

How to Spot Satellites


 

How to Spot Satellites

The streak in the night sky in this photo is actually the International Space Station soaring overhead at 5 miles per second. NASA photographer Bill Ingalls captured this photo in a 30-second exposure on Saturday, Aug. 1, 2015 from Elkton, Virginia.

If you go out and carefully study the sky near dusk or dawn, and you have relatively dark skies, the odds are that you should not have to wait more than 15 minutes before you see one of the more than 35,000 satellites now in orbit around Earth.

Most of these “satellites” are actually just “space junk” ranging in size from as large as 30 feet, down to about the size of a softball.  The Joint Space Operations Center (JSpOC) headquartered at Vandenberg AFB in California, keeps a constant watch on all orbiting debris. Try our Satellite Tracker from N2Y0.com and spot the International Space Station and more!

And in fact most satellites — especially the bits of debris — are too faint to be seen with the unaided eye.  But depending on who’s counting, several hundred can be spotted with the unaided eye.  These are the satellites that are large enough (typically more than 20 feet in length) and low enough (100 to 400 miles above Earth) to be most readily seen a sunlight reflects off them.

The International Space Station (ISS) is by far the biggest and brightest of all the man-made objects orbiting the Earth.

On-orbit construction of the station began in 1998, and is scheduled to be complete by 2011, with operations continuing until around 2015.  More than four times as large as the defunct Russian Mir space station, the completed International Space Station will ultimately have a mass of about 1,040,000 pounds (520 tons) and will measure 356 feet across and 290 feet long, with almost an acre of solar panels to provide electrical power to six state-of-the-art laboratories.

Presently circling the Earth at an average altitude of 216 mi (348 km) and at a speed of 17,200 mi (27,700 km) per hour, it completes 15.7 orbits per day and it can appear to move as fast as a high-flying jet airliner, sometimes taking about four to five minutes to cross the sky. Because of its size and configuration of highly reflective solar panels, the space station is now, by far, the brightest man-made object currently in orbit around the Earth.

On favorable passes, the space station can appear as bright as the planet Venus, at magnitude -4.5, and some 16 times brighter than Sirius, the brightest star in the night sky. Some have made estimates as bright as magnitude -5 or -6 for the station (smaller numbers represent brighter objects on this astronomers scale).

And as a bonus, sunlight glinting directly off the solar panels can sometimes make the ISS appear to briefly “flare” in brilliance to as bright as magnitude -8; more than 16 times brighter than Venus!

Along with the ISS, you can also look for China’s Tiangong-1 space laboratory, which has hosted visiting crews on Shenzhou spacecraft in recent years. Also visible to the naked eye is the Hubble Space Telescope.

Russia’s Soyuz and Progress spacecraft, as well as SPaceX’s Dragon and Orbital ATK’s Cygnus capsules, are much smaller than NASA’s space shuttles (which were also visible to the naked eye until they were retired in 2011). But they could potential be visible under the best observing conditions.

Multiple images of the International Space Station flying over the Houston area have been combined into one composite image to show the progress of the station as it crossed the face of the moon in the early evening of Jan. 4, 2012.

Multiple images of the International Space Station flying over the Houston area have been combined into one composite image to show the progress of the station as it crossed the face of the moon in the early evening of Jan. 4, 2012.

Credit: NASA

During the northern summer, when the nights are the shortest, the time that a satellite in a low-Earth-orbit (like the ISS) can remain illuminated by the sun can extend throughout the night – a situation that can never be attained during other times of the year. Because the ISS circles the Earth about every 90 minutes on average, this means that it’s possible to see it not just on one singular pass, but for several consecutive passes.

Moreover, because the ISS revolves around the Earth in an orbit that is inclined 51.6-degrees to the equator, there are two types of passes that are visible.

In the first case (we’ll call it a “Type I” pass), the ISS initially appears over toward the southwestern part of the sky and then sweeps over toward the northeast.

About seven or eight hours later, it becomes possible to see a second type of pass (we’ll call it “Type II”), but this time with the ISS initially appearing over toward the northwestern part of the sky and sweeping over toward the southeast.

Type I passes will initially be visible in the morning hours, prior to sunrise. By early July, Type I passes will be visible during the evening hours, just after sunset, while Type II passes will be occurring in the early morning.  By late July, visibility of the Type II passes will have shifted into the evening hours.

So what is the viewing schedule for your particular hometown? You can easily find out by visiting one of these four popular web sites:

Each will ask for your zip code or city, and respond with a list of suggested spotting times. Predictions computed a few days ahead of time are usually accurate within a few minutes. However, they can change due to the slow decay of the space station’s orbit and periodic reboosts to higher altitudes. Check frequently for updates.

Some passes are superior to others.  If the ISS is not predicted to get much higher than 20-degrees above your local horizon, odds are that it will not get much brighter than second or third magnitude (10-degrees is roughly equal to the width of your fist held at arm’s length).  In addition, with such low passes, the ISS will likely be visible for only a minute or two.  Conversely, those passes that are higher in the sky – especially those above 45-degrees – will last longer and will be noticeably brighter.

The very best viewing circumstances are those that take the ISS on a high arc across the sky about 45 to 60 minutes after sunset, or 45 to 60 minutes before sunrise. In such cases, you’ll have it in your sky upwards to four or five minutes; it will likely get very bright and there will be little or no chance of it encountering the Earth’s shadow.

While the ISS looks like a moving star to the unaided eye, those who have been able to train a telescope on it have actually been able to detect its T-shape as it has whizzed across their field of view.  Some have actually been able to track the ISS with their scope by moving it along the projected path.  Those who have gotten a good glimpse describe the body of the Space Station as a brilliant white, while the solar panels appear a coppery red.

For evening passes, the ISS will usually start out rather dim and then tend to grow in brightness as it moves across the sky.  In contrast, for the morning passes, the ISS will already be quite bright when it first appears and will tend to fade somewhat toward the end of its predicted pass.  This is due to the change in the angle of sunlight hitting the vehicle.

Lastly, remember that in certain cases, the ISS will either quickly disappear when it slips into the Earth’s shadow (during evening passes) or quite suddenly appear when it slips out of the Earth’s shadow (during morning passes).  This becomes increasingly more likely for passes that take place more than 90 minutes after sunset or more than 90 minutes before sunrise.

 

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