Why Do Rockets Follow A Curved Trajectory While Going Into Space?

Take a look at this picture of the trajectory of a launched rocket:

rocket-from-ground

Do you notice the rather intriguing thing about the path that the rocket follows? Instead of moving in a straight line, the rocket following a curved trajectory. This isn’t a mistake… you will see the exact same thing in every other picture and video of a rocket launch.

Even so, it doesn’t seem to make sense. Rockets are supposed to go into space, right? So wouldn’t it make more sense if they went straight up in a line, rather than following a parabolic path? They’d reach space much faster that way, it would seem. There must be a reason, because rocket scientists tend to be pretty smart, so, why do they not go straight up?

Short answer: Because they want to get into the orbit around the Earth using as little fuel as possible.

Why do rockets launch vertically?

In the context of space technology, a rocket is something that can send people and stuff into space. It’s that thin, cylindrical, very tall vehicle that launches from the launch pad, leaving a humongous cloud of smoke in its wake. In theory, it could launch like an airplane taking off from a runway, but that would require a number of changes in the current designs of rockets, not to mention being downright uneconomical. (Check out Why Don’t Space Shuttles Take Off Like Airplanes?)

rocket launch

Rockets are launched vertically with a tremendous amount of upward thrust, thanks to their own engines and the solid boosters attached to them (which are jettisoned soon after the launch). Following the launch, the rocket’s climb is initially slow; but by the end of the first minute into the ascent, the rocket is moving at a staggering 1,000 mph (1,609 kmph). (Source)

While flying through the sky, a rocket loses a great deal of its energy as a result of air resistance, and it needs to make sure that it attains a high enough altitude when most of its fuel is used up. That’s why a rocket initially flies straight up very fast, as it needs to cross the thickest part of the atmosphere in the least possible distance.

Why does a rocket’s trajectory angle after the launch?

I think that much of the confusion about a rocket’s trajectory stems from the common assumption that most rockets simply want to escape Earth’s gravity and reach ‘space’. While this is not technically incorrect, it does not paint a clear picture.

First off, you should understand that space is not all that far away (you might want to check out: Where does space begin?). If you fly above an altitude of 100 km (62 miles) above Earth, you are officially considered ‘in space’. The US Air Force would call you an ‘astronaut’ if you flew above 80 km (almost 50 miles). Felix Baumgartner’s skydive (he holds the record for the highest vertical free fall without drogue) is famously called a ‘space jump’, even though he only jumped from an altitude of 39 km (around 24 miles).

There’s one singular takeaway from all of this….

Hence, it’s not that rockets simply want to reach ‘space’; they can actually do that using much less fuel. What most rockets really want to do is enter the Earth’s ‘orbit’.

Making it into Orbit

The main objective of most rockets is to reach the planet’s orbit and stay there. In the planet’s orbit, the gravitational tug of the planet is high enough to keep the rocket from drifting off into outer space, and low enough so the rocket doesn’t have to burn huge amounts of fuel to keep itself from plummeting back to Earth.

To enter orbit, a rocket begins to tilt onto its side at first, and gradually increases this tilt until it achieves an elliptical orbit around Earth. That being said, attaining a proper orbital path is not easy; it comes at the cost of huge quantities fuel that are exhausted to attain an incredible horizontal velocity of 28,968 kmph (18,000 mph) (Source). This technique of optimizing the trajectory of a spacecraft so that it attains the desired path is called a gravity turn or a zero-lift turn.

Rocket launch

This technique offers two principal benefits: first, it lets the rocket maintain a very low or even zero angle of attack during the early stages of its ascent, meaning that the rocket experiences less aerodynamic stress. The other advantage is that it lets the rocket use Earth’s gravity, rather than its own fuel, to change its direction. The fuel that the rocket consequently saves can be used to accelerate it horizontally, in order to attain a high speed, and more easily enter the orbit.

In a nutshell, a rocket must curve its trajectory post-launch, if it wants to enter the Earth’s orbit. If it didn’t do that and continued to go straight up, it would eventually reach a point where its fuel would run out and, most likely, it would end up plummeting back to Earth like a stone.

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Stopping habitat loss is the key to saving Canada’s endangered species

Canada has been losing and saving species for a long time. Since European settlement, over 100 species have been lost here. These include plants and animals that are extinct and extirpated and species that are considered historic (no one has seen them in Canada for a long time). The number of lost species varies between different regions of the country. In the Great Lakes region of southern Ontario, there are extinct species (passenger pigeon), extirpated species (paddlefish) and historic species (Eskimo curlew). There are also species that have vanished from this landscape but still exist elsewhere in Canada. This includes large carnivores, such as black bear and cougar, and plants and smaller wildlife, such as white prairie-clover, spring salamander and Melissa blue butterfly.

The causes of species loss in Canada have varied through time, and include over-hunting, pollution, invasive species, habitat loss and climate change. These mirror the threats to species around the world. Canada has made significant progress in reducing some of these threats, and helping some species to recover.

Pronghorn antelope, Old Man on His Back (Photo by Karol Dabbs)

Pronghorn antelope, Old Man on His Back (Photo by Karol Dabbs)

Over a century ago, many of our game and furbearing animals, such as pronghorn, beaver and marten, had vanished from huge areas of Canada because of unregulated hunting and trapping. Many migratory birds were becoming rare because of over-hunting and commercial harvest. Today, trapping and hunting are not a significant threat to endangered species in Canada. We have also seen an extraordinary recovery of species, such as wood duck and river otter.

Peregrine falcon, ON (Photo by Brian Ratcliff)

Peregrine falcon, ON (Photo by Brian Ratcliff)

When I was kid in the late 1970s, I had posters of peregrine falcons and American white pelicans on my wall. Their populations had drastically declined, in part, because of the pesticide DDT. DDT would accumulate in these birds and cause the shells of their eggs to thin and crack. Without new generations of these birds being born, their populations were declining. When DDT was mostly phased out by the mid-1970s, populations of these birds recovered. While there are still some chemicals that are impacting species, we now know that by reducing environmental pollution, species can recover.

Canadians today should be thankful to those who made the changes needed to help wildlife recover. Introducing new trapping regulations, passing the Migratory Bird Act in 1916 to control hunting and protect birds, and the banning of DDT were not simple feats. But they were necessary, and those conservation actions benefit Canadians and Canadian wildlife today.

Today our challenge to save species is also not simple, but it is equally necessary. Of all the threats to species and of all the factors endangering Canada’s wildlife, the challenge to our generation is stopping habitat loss.

Now, you might have thought climate change is our biggest challenge. But to save species, to prevent the further loss of Canada’s wildlife, we need to save habitat. There is no opportunity for species’ recovery if their habitat is lost. Changes in hunting regulations couldn’t have saved pronghorns if there wasn’t any habitat left. And solving climate change won’t protect species if, in our race to reduce carbon emissions, their habitat disappears.

The Green Mountains Nature Reserve, QC (Photo by Appalachian Corridor)

The Green Mountains Nature Reserve, QC (Photo by Appalachian Corridor)

There are many important initiatives to protect habitat for endangered species and wildlife. Canada’s current target of protecting 17 per cent of our land and inland waters by 2020 will help us meet an important conservation milestone, but many of these new protected areas and conservation lands will be in our northlands. This is critical for woodland caribou and wolverines, but many of Canada’s most endangered species live in the southern areas of Canada where most of the land is privately owned. This is also a landscape that is under the most immediate threat. In many regions, we have a one-time opportunity for our generation to protect critical habitats for our most endangered plants and animals.

One of the most important roles of the Nature Conservancy of Canada (NCC), and other land trusts, is to work with private landowners to protect habitat for species that are at risk of being lost from Canada. NCC now protects habitat for over 200 species that have been assessed as endangered, threatened or special concern by the Committee on the Status of Endangered Wildlife in Canada(COSEWIC). This growing number reflects both the increasing number of species assessed as at risk by COSEWIC and NCC’s continued focus on protecting lands that provide habitat for our most endangered species.

Over the last two years, with support from the Government of Canada’s Natural Areas Conservation Program, NCC has documented over 20 new species of endangered wildlife on our properties. Some of these are found on new NCC properties. Some are the result of new information and discoveries, and additions from recent COSEWIC assessments. Some of the species new to NCC’s portfolio of Canada’s endangered wildlife that we help to protect include:

Maritime ringlet (endangered)

The entire range of this small butterfly is restricted to coastal marshes in northern New Brunswick and the southern coast of the Gaspé Peninsula in Quebec. NCC documented this globally rare butterfly in 2016 on a property in the Southern Gulf of the St. Lawrence.

Lark bunting (threatened)

The global population of this grassland bird has declined by 98 per cent in the last 50 years due to habitat loss. When the species was assessed as threatened by COSEWIC in 2017, NCC had already protected over 30 properties in Alberta and Saskatchewan, including the Wideview Complex in Saskatchewan, that provide the shrinking prairie habitats it needs.

Van Brunt’s Jacob’s ladder (threatened)

This globally rare wildflower was recently discovered on an NCC property in Quebec’s Eastern Townships. Van Brunt’s Jacob’s ladder is rare throughout its range in northeastern Northern America and is threatened by habitat loss.

Evening grosbeak (special concern)

This coniferous forest songbird has been declining throughout most of its range. Threats to the evening grosbeak include loss of mature and old-growth forests. This bird was assessed as special concern by COSEWIC in 2016. At that time, NCC was already protecting nesting and stopover habitat across Canada, including Southwest Nova Natural Area in Nova Scotia, Riding Mountain in Manitoba and the Salish Sea in BC.

Hine’s emerald (endangered)

The Canadian distribution of the globally rare Hine’s emerald dragonfly is restricted to the Minesing Wetlands, just west of Barrie, Ontario. In 2017 and 2018, NCC protected two properties where the Hine’s emerald has been recorded. In addition to habitat protection, NCC will also be restoring wetlands on the Patrick W. E. Hodgson Property over the next few years to create additional habitat for this species.

Habitat is the lynchpin of wildlife conservation. There are important successes in recovery and discovery that we need to share. But most importantly, we need to do more conservation and we need to do it faster. No one else can save Canadian wildlife except Canadians.

May 18, 2018 | by Dan Kraus   The Nature Conservancy of Canada (NCC)

 

Dan Kraus

About the Author

Dan Kraus is NCC’s National conservation biologist.

Read more about Dan Kraus.

Amazing Color Photos That Capture Everyday Life of Reno, Nevada From the Early 1960s

Reno is a city in the U.S. state of Nevada. It is in Northern Nevada, approximately 22 miles (35 km) from Lake Tahoe.

Known as “The Biggest Little City in the World”, Reno is famous for its hotels and casinos and as the birthplace of Harrah’s Entertainment (now known as Caesars Entertainment Corporation). It is the county seat of Washoe County, in the northwestern part of the state.

Reno sits in a high desert at the foot of the Sierra Nevada and its downtown area (along with Sparks) occupies a valley informally known as the Truckee Meadows. It is named after slain Union general Jesse L. Reno.

Reno is the most populous Nevada city outside the Las Vegas Valley, and part of the Reno–Sparks metropolitan area, which consists of all of both Washoe and Storey counties.

These amazing photos from Barb Henry were taken by her parents that captured everyday life of Reno from the early 1960s.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

By Barb Henry  May 18 2018

Earliest Portrait Photos Ever Taken Bring Americans From the 1840s to Life After Being Colorized

These amazing photographs were all taken in the 1840s using the daguerreotype which had just been invented. Images show various people from 1840s New York and bring to life how people looked and dressed in that era. They believed to have been taken by legendary early American photographer Matthew Brady, show a selection of 11 portraits taken as daguerreotype images.

 

 

 

 

 

 

 

 

 

(Images: My Colorful Past/mediadrumworld, via Daily Mail)  May 18, 2018

Vikings in our Midst: the Jorvik Viking Centre brings the past to life based on archaeological findings

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A Burning Wicker Wolf heralds the re-opening of the Jorvik Viking Centre. The centre was badly damaged during the 2015 flooding in the city and has since undergone extensive refurbishment work. (Photo by Ian Forsyth/Getty Images)

The United Kingdom was once a very un-united group of territories. They were governed by a variety of groups, including the Romans, Britons, Angles, Saxons, Danes, and Norsemen. In the words of Thomas Hobbs (while not referring to the very early Middle Ages specifically), life was indeed “nasty, brutish and short.”

Present-day York, in North Yorkshire, England, dates back to at least the Roman era (although likely even earlier), when it was founded as the Roman fortress of Eboracum, and in its prime was the provincial capital and the largest town in Northern Britain.

After the fall of the Roman Empire and withdrawal of Rome from Britain, Eboracum became an Anglo-Saxon trading centre called Eoforwic. It came under Danish control in 867 A.D., and Jorvik was born.

The term Jorvik actually referred to a greater area than just the urban settlement; it included the south of Northumbria, or much of modern-day Yorkshire. Even once it was controlled by the Danes, the area was still subject to invasion and short periods of rule by the English in the mid-10th century, until it was annexed by England in 954 A.D. Jorvik, or York, had great economic importance in the region, possessing a mint, and the Viking king Guthred was buried in York Minster. Eventually, after the Viking kingdom was absorbed into England, the title King of Jorvik eventually became that of the Earl of York in 960 A.D.

Fast-forward a little over 1,000 years to 1976 when the York Archaeological Trust began a five-year excavation in the vicinity of Coppergate in central York. During the archaeological dig, remains were found of several wooden structures dating from Viking Jorvik, as well as metal, leather, textile fragments, pottery, metal, and bones. Although the site was 1,000 years old, the items were well preserved due to the wet clay soil, which deprived the artifacts of oxygen, therefore preventing them from disappearing completely. Over 40,000 objects were uncovered in the end.

Cool Viking Facts

As a result of this treasure trove of Viking objects, the Jorvik Viking Centre was opened in 1984–less than 10 years after the dig started. The York Archaeological Trust used the evidence found at the site to re-create part of what a streetscape in Jorvik would have looked like, complete with lifelike mannequins, soundscapes, and even smells, including the fish market, pig sties, and latrines.

This multi-sensory experience completely immerses visitors in the Viking age, and gives them the chance to step back in time, even if only temporarily.

The center underwent extensive renovations in the early 2000s, and reopened as a “new and improved” version in 2017. The Ride Experience, which visitors take through the re-created town, is now a bit slower, allowing more time to take in all of the sights, smells, and sounds.

The traditional museum area includes about 800 items from the archaeological site, as well as interactive displays and museum staff in character as people from the era portrayed. Even the mannequins have been carefully thought through. Facial recognition technology was used to re-create the highly realistic figures based on human skulls found in a cemetery that dates from the Viking Age.

Visitors encounter many characters at Jorvik, including the Hunter and his dog, a slave trader, blacksmith, fisherman, weaver, and an Arabic trader. Interestingly, in addition to a Viking storyteller, there is also a priest, acknowledging that while the Vikings who came to Britain’s shores were not Christians, they adopted the religion relatively quickly, and there is evidence of a Viking-age church to the rear of Coppergate.

One of the great appeals of the United Kingdom, and indeed Europe as a whole, is the layering of history that can be found almost everywhere. York is a prime example of such layering–from pre-Roman through the Roman era, Viking, medieval, and modern, all mixed together in one city. The Jorvik Viking Centre is a must-see in York, but happily just one of several sites of great interest there, and throughout Great Britain.

 Patricia Grimshaw

An Australian railway man saved more than 2 million babies—including his own grandchild—with a simple donation of blood

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James Harrison. Photo by: Australian Red Cross

An Australian man who required blood transfusions to survive surgery as a teenager decided to repay the kindness of strangers by becoming a blood donor himself. Little did he know at the time that his blood contained a rare antibody required for a life-saving medication. By the time he retired from donating this month, James Harrison had saved an amazing estimate of 2.4 million babies!

James Harrison came to blood donation from personal experience. When he was 14 years old, he underwent major lung surgery that took hours and required a vast quantity of transfusions—13 units of blood, in fact. He remained hospitalized for three months. So he decided to pay it forward as soon as he could. In Australia, blood donors must be a minimum of 18 years old; so in 1954, when he turned 18, Harrison gave his first units of blood. Despite a fear of needles, he returned to donate every few weeks for a remarkable 60 years.

But the Good Samaritan’s good deed turned out to be more beneficial than he ever could have imagined. In the 1960s, researchers discovered that Harrison’s blood contained a rare antibody used in a medication called Anti-D that helps save babies from a potentially fatal disease. The Australian Red Cross reports that Harrison’s blood has been used in more than 3 million doses of Anti-D since 1967, and that he has helped save the lives of 2.4 million babies, including that of his grandchildren. His daughter, Tracey Mellowship, received the injection and had two healthy babies. The Red Cross called him “the man with the golden arm.”

The Anti-D injections are given to pregnant Rh(D) negative women carrying Rh(D) positive babies, whose blood-type incompatibility can result in miscarriage, brain damage, or even stillbirth, according to the Australian Red Cross. Around 17 percent of Australian women need the injections, which come only from blood plasma from a “tiny pool” of around 160 donors who have the rare antibody that Harrison has. Attempts to make a synthetic version of the medication have so far failed.

Harrison had been donating for a decade when researchers discovered his blood was perfect for their new Anti-D program.

A Man Saved A Condor Years Ago And The Bird Still Flies Back To Say Thanks

On May 11, Harrison, now 81 and retired from his job as a railway administrator, lay back and had his arm strapped and swabbed as he got ready to give his last donation. As always, he looked away from the needle, and gripped a stress ball in his other hand. Medical officials with the Red Cross said it was time for Harrison to retire and save his blood for his own health. He received the Medal of the Order of Australia in 1999 for his service to the Anti-D program. He also made it into the Guinness Book of World Records in 2003.

Harrison’s last donation at the Town Hall Blood Donor Center in Sydney was videotaped and shown on the local TV news. (Harrison, ever the proper railway man, wore a tie to the occasion.) Helium balloons above his head had the numbers 1, 1, 7, and 3 to represent the 1,173 times he had donated blood. A half-dozen moms who had benefited from the Anti-D injection program showed up, their babies in their arms, to commemorate the unassuming hero.

“The end of an era,” Harrison, who lives in New South Wales, told the New York Times. “It was sad because I felt like I could keep going.”

Harrison was proud of having helped though not unduly vain about his accomplishment. He hopes the publicity surrounding his retirement will inspire other blood donors to come forward; perhaps one will also carry the rare antibody.  “Saving one baby is good,” Harrison told the New York Times. “Saving two million is hard to get your head around, but if they claim that’s what it is, I’m glad to have done it.”

 E.L. Hamilton