Connect with us

Published

on

Timeline of History Of Earth

 

5 billion years ago :

  • There are stars and dust around the sun. Earth hasn’t formed yet. With time, gravity works to hold these rocks and dust to form planets.

 

4500 million years ago: 

  • Earth has been formed. Temperature is over 2000 F. The atmosphere is made up of carbon dioxide, nitrogen and water vapor. And the earth surface is just an endless ocean of boiling lava.
  • Young hypothesized proto-planet Theia collides with the Earth, sending large number of moonlets into orbit around the Earth which eventually coalesce to form the Moon.
  • The entire day lasts only 6 hours.

 

3900 million years ago:

  • Although the core is still molten, the surface cools down to 70-80 degree celsius, forming crust.
  • The crust will allow the formation of oceans, from the water being carried by the continuous meteors shower occurring in the solar system.
  • With time, moon moves away causing the planet to spin slower.

 

3800 million years ago:

  • The lava bursts and form volcanic islands. But even with land and water, the temperature and atmosphere, however is not yet favorable for life.
  • As the meteors that have been falling down dissolve with water, they release minerals, carbon and primitive amino acids, turning water into the Chemical Soup. From this, the earliest form of life on earth is formed – Single celled bacteria (Prokaryotes).

 

3500 million years ago:

  • Stromatolites emerge on the bottom of the shallow ocean, with the extra ordinary capability of ”Photosynthesis”.  They slowly fill the oceans with oxygen.
  • The oxygen turns the traces of iron in the water into rust. These rusts accumulate in the ocean floor to form deposits of iron rich rocks.

 

1500 million years ago:

  • The temperature is 30 degree Celsius and days are now 18 hours long.
  • The core is so hot that it creates movement in the rock beneath the crust. As a result, the crust is broken into vast plates. The movement rearranges the plates and over 400 million years, a vast new super continent is formed called “Rodinia”.
  • Beneath the oceans, the stromatolites are still working their magic to create more oxygen.

 

750 million years ago:

  • As the heat inside the core tries to escape, it tears the crust apart and centimeter by centimeter, year by year, the great supercontinent splits in two.
  • The carbon dioxide emitted by continuous volcanoes mix with atmosphere to form acid rain, which is absorbed by rocks. However, there is not enough carbon dioxide to absorb sunlight.

 

650 million years ago:

  • In a few thousand years, the temperature plummets into -50 degree Celsius, giving rise to what the scientists called “The Snowball Earth”.
  • During this event, the entire planet is covered with ice as thick as three kilometers. Virtually, all the sunlight and warmth reflects back into space. It is believed to be the longest ice age to grip the planet.
  • Although the surface is frozen, the core is still hot. The carbon dioxide being emitted from volcanoes eruption, which now cannot be absorbed by the rocks as it’s covered by ice, forms a blanket of CO2 around the earth trapping the heat. After 15 million years, slowly the ice begins to melt.

 

600 million years ago:

  • The days last for 22 hours now and the climate is warmer.

 

540 million years ago:

  • Although the kind of glaciation in “The Snowball event” would have made life extinct entirely, some of the primitive life form clung through the Ice age and now a new life form- the first multi cellular organisms can be found.
  • Life in the ocean starts to blossom.

 

460 million years ago:

  • Even though there is life in ocean, the life on land is next to impossible due to lethal radiation from sun. However, ozone layer is in the process of formation.

 

375 million years ago:

  • Ozone layer has formed and the Earth is now shielded from radiation.
  • First land plants emerge.
  • The first tetra-pods evolve. From these creatures, all other four legged creatures like dinosaurs, birds, reptiles, mammals etc will evolve.
  • A major evolutionary breakthrough in this period is laying of eggs on the land.

 

250 million years ago:

  • The Siberian eruption leads to “Permian extinction”, which eliminates up to 96% of marine species and 70% of terrestrial vertebrates.

 

200 million years ago:

  • There is one single super continent “Pangea”, stretching from pole to pole.
  • The planet is healing, temperature stabilizing and vegetation returning. After the mass extinction, new species emerge- “The Dinosaurs”, which evolved from the handful of reptiles that survived the Permian extinction.

 

190 million years ago:

  • The Pangea breaks up and forms two continents. The chasm between two continents subsequently forms a new ocean “The Atlantic”.
  • Due to continuous eruptions and lava forcing its way out, new range of volcanic mountains are formed.

 

65 million years ago:

  • An asteroid 10 kilometers in diameter, travelling at speed of over 70000 km/hr hit the Earth and causes the Cretaceous–Paleogene extinction event with eradicating about half of all animal species, including the dinosaurs but excluding their descendants, the birds.
  • Purgatorius, a rat-sized placental mammal, becomes the earliest example of a primate or a proto-primate, which will later give rise to monkeys, apes and humans.

 

47 million years ago:

  • The temperature is 24 degree and days are under 24 hours, almost like our Earth we call home now.
  • Plates are in constant state of movement, forming a vast mountain range “ The Himalayas”.
  • Mount Everest is formed.

 

20 million years ago:

  • All the continents and oceans that we know today, have now been formed.
  • Some modern animals such as giraffes, hyenas, bears appear with increase in bird and mammal diversity.

 

4 million years ago:

  • Earliest bipedal emerged.

 

1.5 million years ago:

  • Homo Erectus were found.

 

70000 years ago:

  • The climate changes again. Sea levels fall and the gap between Africa and Arabia shrinks down to just 13 kilometers, making it easy for anatomically modern humans (Homo Sapiens)  to leave Africa and colonize other continents.

And then begun the Chapter of Humans.

 

curlyhead exploring life and spirituality

Continue Reading
Click to comment

Leave a Reply

Your email address will not be published.

Health&Sports

Myopia Management & OrthoKeratology

Published

on

If you are wearing glasses, you surely do remember your first visit to your eye doctor. Many of you might have been prescribed spectacles or contact lenses as a remedy to the refractive correction (Glass Prescription). As a small kid, I remember my eye care professional prescribing me a -0.75 refractive correction (lens power) when I was around 11 years old.  By the time I was 20 years old, my refractive correction was -2.75.  I always used to wonder and ask myself why my refractive correction was increasing even though I was wearing spectacles as prescribed by my eye care professional.  Could this -2.00 Diopter of increase in power have been controlled?  Is there any way we can help children of 4 to 5 years, already having -1.00 Diopter of correction, stop them from becoming high Myopic (>-6.00 D) when they grow? Should we really worry about myopia control in children? What are the risk factors that comes after having a high myopia?



We have to be asking all these questions now and try getting the answers.  One of the reasons of Myopia progression is due to the elongation of the eyeball with its increase in axial length.  Myopia control wizards (Optometrists) have been trying their best to control this phenomenon of increasing the axial length of the eye ball to control the Myopia progression. Controlling Myopia does not just improve the patient’s quality of life but it also prevents vision threatening conditions like retinal detachments and retinal maculopathy.  Now, the question arises how do we control this normal phenomenon of the elongation of the eyeball? Luckily for us, many researchers has already found a way to control this phenomenon by various methods.

  1. Simply get out of your room and play outside:  Sounds simple yet very effective. If you want your children, brothers or sisters to be less vulnerable to refractive error, then send them outside to play. Though the exact reason for this is not known yet, many researchers have found out that spending just about 10 to 12 hours a week outside the room and indulging in outdoor activities helps to reduce myopia progression in Children.Hence, taking kids out of their digital gadgets and spending time outdoors can be beneficial in reducing Myopia progression.
  2. Low Dose Atropine: A low dose atropine of 0.01% is considered to be really helpful in controlling the progression of Myopia. The ATOM & LAMP trials study has shown that low dose atropine of 0.01% & 0.05% is more effective than 1% atropine with much less side effects and rebound effect. 2, 3
  3. Multifocal Contact Lens: The use of center distance design Multifocal Contact Lenses helps to reduce the elongation of the eye ball by creating a myopic defocus in the periphery of the retina. With normal spectacle and contact lenses, hyperopic defocus is created in the peripheral retina which makes the peripheral retina to elongate in order to focus the light rays into the retina. The center distance multifocal lenses has high add in the periphery which corrects this hyperopic defocus and pushes the light rays in front of the retina creating a myopic defocus which helps to control the elongation of the axial length of the eye ball.
  4. OrthoK Lenses: The OrthoK lenses corrects the Myopia by flattening the center of the cornea without the need of surgery. As in LASIK surgery, the OrthoK lenses helps to flatten the central corneal area which corrects the Myopia. The peripheral cornea creates a myopic defocus that helps to control the Myopia progression as well. The OrthoK lenses are the gold standard treatment for myopia control and is also one of the options for myopia correction.

Why should we worry about Myopia Progression?

Myopia progression today has become a topic of discussion for many of the eye health care practitioners. It is estimated that by the year 2050 about half of the world’s population will become myopic. So, if something is not done to control this progression, we will be seeing rise in more and more myopic patients in the days to come. But why should we actually worry about Myopia Progression?

With this digital age, children today spend most of their time in their electronic devices which is turning them into an early Myopes. We are now getting myopic cases more than ever. It is common to find more than -1 Diopter of Myopia in children of 5 to 6 years. If this is not corrected and controlled, these children are bound to become high Myopic at the age of 18. With high Myopia comes the high risk of many eye health conditions like Cataract, Glaucoma, Retinal Detachment & Maculopathy.

The only goal of Myopia Control & Orthokeratology is to stop these children from progressing from -1 Diopter to -6 or -7 Diopters.  If we can start Myopia Control now, the Myopia progression can be controlled by more than 50% and these children can be saved from the risk factors of high Myopia.

Conclusion:

We are treating Myopia as a refractive error but now it’s time to take myopia as a disease and start treating it and help those children from progressing their myopia to become high Myopic. If you are a parent, brother or sister of a young myopic child, then please do start talking about myopia control with your eye health care professionals. Pediatric Ophthalmologists along with Optometrists who practices Myopia Control can stop the progression of Myopia. Refractionists and Ophthalmic Assistants can help you find if your children has any refractive errors and will refer you to the Myopia Control practitioner.

 





References:

      1. Wu PCChen CTLin KK, et al. Myopia Prevention and Outdoor Light Intensity in a School-Based Cluster Randomized Trial. Available from: https://www.ncbi.nlm.nih.gov/pubmed/29371008
      1. Li FFYam JC. Low-Concentration Atropine Eye Drops for Myopia Progression. Available from: https://www.ncbi.nlm.nih.gov/pubmed/31478936
      1. Yam JCJiang Y, et al. Low-Concentration Atropine for Myopia Progression (LAMP) Study: A Randomized, Double-Blinded, Placebo-Controlled Trial of 0.05%, 0.025%, and 0.01% Atropine Eye Drops in Myopia Control. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30514630
Continue Reading

Health&Sports

Things to know before buying a Soft Contact Lens

Published

on

When we get a prescription for refractive correction we start thinking about spectacles. Spectacles has become a very good means of correcting refractive error but sometimes we do want to break free from the glasses and enjoy our coffee without the fog, enjoy rain without the blur & enjoy the dance floor without worrying about the glasses. There are various other options that we can choose if we are fed up with the spectacles. The very first option that I, as an Optometrist suggest to my patients are Contact Lenses. But before buying Contact Lenses we should always know about these wonderful invention and the way to handle it.



Should I buy Contact Lenses Online?

We find a lot of online stores selling contact Lenses these days but is it a right way to get your contact lenses? If I was an owner of an online store I might have said, “Contact Lenses are just like spectacles you can buy anywhere you want if you have the prescription” but being an Optometrist I know the risk of buying contact lenses without proper fitting and evaluation of your eye health conditions. Buying your contact lenses is fine if the seller can arrange an eye examination from an eye health care practitioner who is authorized to dispense contact lenses but it can lead to serious complications if you buy those contact lenses without consulting with a contact lens practitioner.

How long can I wear a Contact Lens?

If you can understand how long you can stay underwater without oxygen then you will get your answer of how long a contact lens can be worn. This is just an analogy but when the Contact lens sits in front of your eye ( the Cornea ), the time that it can be worn depends upon how much oxygen can be passed into the cornea through the contact lens. This is determined by the property of the contact lens material called Oxygen permeability (Dk). When contact lenses are made with the material having certain Dk the amount of oxygen that will go through that contact lens will now be dependent upon the thickness of the contact lens which will be termed as oxygen transmissibility (Dk/t). So every material with which the contact lens is made has a Dk value.

Now the actual question of how long a contact lens can be worn will be dependent upon the dk/t value of the lens.

For Daily Wear modality lenses ( lens that are worn on day for 10 to 14 hours ), the Dk/t value according to Holden & Mertz criteria is 24 x 10-9

For Extended Wear Modality lenses ( lens that are worn overnight while sleeping ) the Dk/t value according to Holden & Mertz criteria is 87 x 10-9  

Another thing to know in order to understand how long you can wear a contact lens is to know the replacement schedule of the contact lens. This means when you should dispose your lenses.

There are currently four contact lens replacement schedule:

  1.  Daily Disposable Contact Lens
  2.  Biweekly Disposable Contact Lens
  3.  Monthly Disposable Contact Lens
  4.  Yearly Disposable Contact Lens

The daily disposable lenses are worn and disposed every day. So you can wear a fresh pair of lenses every day. This type of contact lens usually come in a 30 or 32 piece lens in a box. Some of the Contact lens also comes in a small eco pack of 4 to 8 piece lens in a box. These lenses are the most recommended contact lens to wear because of very less chance of infections and other complications because every day the lenses are disposed and a new one is worn. Because these lenses are daily disposable you will not need any lens care solution to clean these every day. Simply dispose it and use a new pair of lens. Do Not wear the same daily disposable lenses more than 1 day.

The biweekly disposable lenses are worn and disposed in every two weeks. That means you store these lenses in a lens storing case for 2 weeks and get a new pair after 2 weeks. The lenses are worn each day for 8 to 14 hours depending upon the contact lens material and removed and stored in a lens case after cleaning. The lenses should be cleaned with a lens care solution every day before wearing and after removing during the 2 weeks period time of wearing. These lenses will come in a 6 piece lens pack. That means when you buy one box of biweekly disposable lens you will have 6 lenses to wear and each lens can be worn for 2 weeks. Do Not wear the same biweekly disposable lenses for more than 2 weeks.

The monthly disposable lenses are worn and disposed in every one month. Similar to biweekly you should clean these lenses every day with lens care solution for the period of one month and dispose it at the end of the month and wear a new one. The lenses are worn each day for 8 to 14 hours depending upon the contact lens material and removed and stored in a lens case after cleaning. These lenses will also come in a 6 piece lens pack and you can wear each lens for 1 month.  Do not wear the same monthly disposable lenses for more than 1 month.

Yearly disposable lenses are not prescribed in western and developed countries now a days because of high chances of infection and complications than other disposable lenses. They usually come in a pair and the same lens is worn for a year. Similar to monthly and biweekly these lenses should be cleaned every day with a lens care solution. These lenses are not usually recommended to wear.

In short, while buying a contact lens you should know which replacement schedule contact lens you need ( daily, biweekly, monthly or yearly) and when to dispose it. Before buying any lenses make sure you have a detailed eye examination and after buying the lenses make sure you are taught how to correctly insert and remove the lenses with proper maintenance and lens handling.

Summary:

Contact Lenses are great alternative for your spectacles. There are daily disposables, biweekly disposables, monthly disposables and yearly disposables contact lens currently in market. Make sure to choose the right one with the help of your Optometrist. Don’t buy any contact lens without consulting with an Optometrist and make sure you are taught the proper way of lens care and maintenance. A good Optometrist will always help you to make you comfortable with your contact lens.

( Only Soft Contact Lens is discussed in this article. There are many other contact lens which are used as specialty contact lenses )




Continue Reading

Business

What is Seed Capital?

Published

on

Just how a germinating seed needs water, sunlight and proper nutrients to grow into a beautiful plant, any budding entrepreneur also needs funds to implement his/her startup ideas. This initial investment which helps to cover up the basic operating expenses, research and development expenses etc to grow the business until the product itself starts generating revenue is called Seed capital or Seed funding. Generally, seed capital is considered as the first round of investment until one develop his/her business to a certain level after which he/she can find venture capitalists to invest in them. So, where does the seed capital come from? Some of the easy sources may include :

  1. Friends or Family
  2. Crowd Funding
  3. A seed-stage angel investor
  4. Corporate seed funds for startups
  5. Self – financing
  6. Government subsidized loans and grants

Finding an investor can be a challenging task as your startup is still in conceptual phase. Generally, the banks often ask for collateral against the applied loan. Even more, the interest rates may be high and not every person can afford to take the risk. On the other hand, investors may invest in you and your idea in exchange for certain equity in stake. This means you will be losing your share of full decision making authority over your business in exchange for his contributed amount of capital. However, reaching out for friends and family or using your own savings is always a good idea if you don’t want to get involved in debt. There are also government grants and subsidized loans in recent years that plan to support to aspiring entrepreneurs in the country. So, before you make your decision, make sure to do a good research and weigh all the pros and cons of each source to find one that actually compliments your business model, as it plays a determining role in the future of your business.

The author is a CA student.  If you want to add more information on the given post, please comment below and your comment will be incorporated in the article.


SINCE YOU ARE HERE:

Join Our Team:

  • Do you love writing? Be our writer.  CLICK HERE for more details.
  • We are looking for Interns.  Mail your CV to [email protected].

Show Your Support: 

Running a media is a costly work, especially when are quality driven.  Show your support by:

  • SHOP TO SUPPORTCLICK HERE to explore our e-commerce page and make a purchase.
  • DONATION:  Your small donation can make a difference.  Express your interest by mailing us to [email protected]

Help Us Getting Better:

We put our utmost effort in creating genuine contents, factual and rational, and been working  hard to give best experience to our readers and users.  However, there can be mistakes, glitches and lapses.  Help us getting better by correcting us whenever you notice false information or wrong facts in our posts.  You can do that by commenting on the post or by mailing us in [email protected].  Also, if you experience any bug in our website or any kind of issue in our website, let us know immediately by mailing us.

Thank you for your time.  We are better together.

Continue Reading
Advertise With Us
Advertisement

Shop To Support

Latest Posts

Follow Us on Facebook

Featured

Popular