Category Life on Earth

Is Earth the only planet that supports life?

Discovery about an Earth-like planet orbiting an M dwarf could imply that planets orbiting the most common star may be uninhabitable.

Is Earth the only planet that supports life? This is one of the many questions for which we don’t have an answer yet. In a universe filled with countless stars and innumerable planets, our quest for life on a planet other than our own continues.

A new discovery could serve as a signpost and maybe even dramatically narrow our search for life on other planets. The discovery, explained in the Astrophysical Journal Letters in October by researchers from the University of California – Riverside, reveals that an Earth-like planet orbiting an M dwarf appears to have no atmosphere at all.

Most common type of star M dwarfs or red dwarfs are the most common type of star in the universe. This discovery could therefore imply that a large number of planets orbiting these stars may also lack atmospheres, and will therefore likely not support life.

The planet named GJ 1252b is slightly larger than our Earth, but is much closer to its star, an M dwarf, than the Earth is to the sun. On a single day on Earth, this planet orbits its star twice.

In order to find out if this planet lacks an atmosphere, astronomers measured infrared radiation from the planet as its light was during a secondary eclipse. In a secondary eclipse, the planet passes behind the star, and hence the planet’s light along with the light reflected from its star are blocked.

Scorching temperatures

The radiation revealed the planet’s daytime temperatures to be of the order of 2,242 degrees Fahrenheit. This, along with assumed low surface pressure, led the astronomers to believe that GJ 1252b lacks an atmosphere.

The researchers concluded that the planet will not be able to hold on to an atmosphere, even if it had tremendous amounts of carbon dioxide, which traps heat. Even if an atmosphere builds up initially, it would taper off and erode away eventually.

With M dwarf stars having more flares, the likelihood of planets surrounding them closely holding onto their atmospheres goes down further. The lack of atmosphere means that life as we know it is unlikely to flourish.

In Earth’s  solar neighbourhood, there are about 5,000 stars and most of them are M dwarfs. If planets surrounding them can be ruled -out entirely in the search for life based on this discovery, that would leave roughly around 1,000 stars similar to the sun that could be habitable.

For now, however, these can’t be ruled out entirely. Nor can we rule out the possibility of a planet far enough away from an M dwarf star such that it retains its atmosphere. We need more research and results as we continue to embark on our search for life elsewhere.

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WHAT ARE THE FUN FACTS ABOUT BUTTERFLIES AND MOTHS?

Butterflies and moths are both part of a big group of insects that have wings covered in tiny dust-like scales. Butterflies are usually brightly coloured and they fly during the day. They have a thin, hairless body and a pair of antennae each with a small bulb at the end. Moths tend to be duller in colour so they are camouflaged when they rest during the day on trees and leaves. They have antennae and plump, hairy bodies. Butterflies tend to fold their wings vertically up over their backs. Moths tend to hold their wings in a tent-like fashion that hides the abdomen. Butterflies are typically larger and have more colorful patterns on their wings. Moths are typically smaller with drab-colored wings.  Reason we dislike moths is that they normally come out at night, whereas butterflies are active in the day. While we sleep, dozens of species of moths fly around, attracted to light and looking for mates.

1. Butterflies and moths are part of the same group of insects, known as ‘Lepidoptera’. To tell them apart, butterflies fly in bright sunshine, while moths are most active at night.

2. The lifecycle of a butterfly is in four stages: egg, caterpillar, pupa and adult butterfly.

3. Most butterflies don’t live very long. The Priam’s birdwing butterfly only lives for 10 days!

4. Butterflies have four wings, not two as you may think.

5. The wings of butterflies and moths, with their vibrant colours and patterns, are actually made up of tiny scales.

6. The largest butterfly in the world is the female Queen Alexandra’s birdwing, with a wingspan of over 25cm!

7. The smallest butterfly is the Western Blue Pigmy, which is only 2cm across.

8. Butterflies need heat to be able to move. When you see them resting in the sunshine, they are warming up their wings so they can fly.

9. Moths have a stronger sense of smell than butterflies.

10. Butterflies can see colours that humans can’t.

11. Moths navigate using the moon. This means they also are attracted to man-made lights, which cause them to get lost.

12. Butterflies taste with their feet!

Credit : Penguin.com 

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WHAT IS THE TIMELINE OF LIFE ON EARTH?

Just as the day is divided into hours, minutes and seconds, geologists divide Earth’s history into time periods. The longest divisions are aeons, which are billions of years long; the shortest are chrons, a few thousand years long. In between come eras, periods, epochs and ages. Scientists divide the last 590 million years into three eras: the Palaeozoic (meaning ‘old life’), Mesozoic (‘middle life’), and Cenozoic (‘new life’).

Humans have only been a species in the most recent chapter of the history of Earth. The Earth was formed 4.6 billion years ago, when the sun in our solar system first formed, creating enough gravitational pull to spin planets into orbit. But how do scientists know how old the Earth is if humans weren’t around back when it was formed? When was life first formed on this planet? And what are the paths that life has taken so far over the course of that existence? This lesson will teach about the ages that make up the history of life on Earth, and explore the many changes and forms life has taken in its time on this planet.

Timeline of Geological Eras

The geological timeline of Earth is nearly identical to the history of life on Earth, apart from the Hadean Era. This is because the geological timeline, or the order of geological events, such as oceans forming, volcanoes erupting, how long deserts lasted, and tectonic plate movement, all happened in sequence with the life that has existed on this planet. The history of both life and the geological timeline is arranged within 5 subgroups, arranged from the largest span of time to the smallest: eons, eras, periods, epochs, and ages. To understand the timeline of life that has existed on Earth, it is important to understand how scientists determine the age of both rocks and the remnants of living things, otherwise known as fossils.

Because humans were not around 4.6 billion years ago to record the beginnings of our planet, scientists must rely on evidence from geological and fossil records in order to determine the relative age of both the planet and the life that exists here. Both the geological timeline and the age of life are determined in much the same way. Modern scientists rely on what is called radioactive dating to determine an accurate and precise age of both rocks and fossils. Radioactive dating measures the rate of decay of an element in a rock or in a fossil. Carbon-14 is typically used when dating fossils because all living things are carbon-based, and the flow of carbon can be tracked through the carbon cycle. For geological objects such as rocks and minerals, Rubidium-87 and Potassium-40 are often used. By knowing how long it takes for molecules in an object to decay, scientists can calculate when the object’s half-life is. The half-life of an object refers to the amount of time it would take for half of an amount of a substance to radioactively decay, or break down. If the half-life of an object is known, it is possible to calculate when the object was first created, when no decay is evident.

Credit: study.com

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