Category Astronomy

Why do the footprints of astronauts remain unchanged on the surface of the moon?

We are pretty proud of the human flight to the Moon and our footprints on the lunar surface. But did you know these footprints can last a million years on the surface of the Moon? It has been decades since humans last set foot on the Moon, but its surface is still marked with the historic footprints of the 12 astronauts who walked across it Unlike on Earth, there is no erosion by wind or water on the Moon because it has no atmosphere. The Moon is geologically inactive there are no earthquakes or volcanoes. So, nothing gets washed away and nothing gets eroded.

However, the Moon is exposed to bombardment by meteorites, which change the surface. One little spacerock could easily wipe out a footprint on the moon. And since the Moon has no atmosphere, it is exposed to the solar wind, a stream of charged particles coming from the sun, and over time this acts almost like weather on Earth to scour surfaces on the moon, but the process is very, very slow.

On July 20, 1969, Neil Armstrong put his left foot on the rocky Moon. It was the first human footprint on the Moon. They had taken TV cameras with them. The two astronauts walked on the Moon. They picked up rocks and dirt to bring back to Earth. The astronauts had much work to do. Then, the Eagle went back to meet astronaut Collins. He was in the Command Module working.

When Neil Armstrong and Buzz Aldrin visited the moon 50 years ago, they left roughly 100 objects behind, including a portion of their lunar lander, the American flag and, yes, various kinds of trash. Those objects are still there, surrounded by rugged bootprints marking humanity’s first steps on another world. But that site, called Tranquillity Base, may not be as enduring as the legacy those prints represent.

Picture Credit : Google 

What is future of the sun?

Nothing in the Universe is permanent. One of the most profound rules in all the Universe is that nothing lasts forever. With gravitational, electromagnetic and nuclear forces all acting on matter, practically everything we observe to exist today will face changes in the future. Even the stars, the most enormous collections that transform nuclear fuel in the cosmos, will someday all burn out, including our Sun. In about five billion years, the Sun will exhaust the hydrogen fuel in its core and start burning helium, forcing its transition into a red giant star. A red giant is a dying star in the final stages of stellar evolution. When the Sun turns into a red giant, it will expand and engulf the inner planets- possibly even Earth. After spending about one billion years as a red giant, the star will become a white dwarf, packing most of its initial mass into a sphere roughly the size of Earth. It will eventually become a black dwarf.

In about 5 billion years time the Sun will have exhausted all the hydrogen at its core. The core, which by then will consist of helium nuclei, will then shrink and nuclear reactions will take place in a large shell outside the core, rather than the core itself. The outer regions of the Sun will greatly expand and it will become a red giant.

It is unclear exactly how large the Sun will get when it becomes a red giant. Current estimates are that it will expand to 100-250 times its current diameter (ref 2). If we take the lower value, the innermost planet Mercury (but not Venus and the Earth) will be swallowed up by the Sun.  At the higher value, the Earth would also be inside the Sun.

When all of the helium in the core has been converted into carbon, nuclear reactions in the core will once again stop. The Sun will start to convert helium into carbon in a shell outside its core but will become more and more unstable. It will vary widely in brightness as it flares up and ejects some of its outer layers into space and then contracts again. Eventually the whole of the outer regions of the Sun will be blown away forming a glowing shell of plasma called a planetary nebula.

With the lower value, where the Sun expands to 100 times its current radius  value, on Earth the Sun would appear 10,000 times larger than it is today. The surface temperature of the Earth would be around 1500 degrees Celsius, hot enough for it glow a dull red colour. The Earth would have lost its atmosphere long before this and will be a bone dry scorched airless desert on which it will be impossible for life to exist.

Credit : Explaining Science

Picture Credit : Google 

Did the fruit flies survive in space?

Fruit flies were the first organisms sent to space. For many years before sending mammals into space, such as dogs or humans, scientists studied Drosophila melanogaster (the common fruit fly) and its reactions to both radiation and space flight to understand the possible effects of space and a zero-gravity environment on humans. Starting in the 1910s, researchers conducted experiments on fruit flies because humans and fruit flies share many genes. On February 20, 1947, fruit flies became the first living and sentient organisms to go to space and return, which paved the way for human exploration. At the height of the Cold War and the Space Race, flies were sent on missions to space with great frequency, allowing scientists to study the nature of living and breeding in space. Scientists and researchers from the Soviet Union and the United States both used fruit flies for their research and missions.

Fruit flies have been used in recent years as the reality of Mars and Moon colonization becomes clearer. These flies further the understanding of the effects of weightlessness on the cardiovascular system, the immune system, and the genes of astronauts. Fruit flies have been invaluable assets to scientific discoveries that humankind have made, especially discoveries about space travel.

Mankind has long admired the heavens and wondered about space. Even after the Space Race was completed, advancements in space travel continued. Researchers continue to study the ability of life to survive in the harsh atmosphere of space, promote commercial development, expand and advance knowledge, and prepare future generations for exploration. Throughout time, Animals in space have ensured suitable conditions for human exploration. Larger animals including dogs, monkeys, cats, mice, and others, have been vital to many excursions, as have insects.

The fruit fly has frequently been utilized for space travel, due to its comparable genetics to that of humans. The short gestation period and quick maturing process allows their continued use. Additionally, a female fruit fly can lay one hundred eggs daily, and each egg requires less than ten days to fully mature. Since three-quarters of its genome compares to other organisms, fruit flies frequently proceed humans in space travel because their entire genetic makeup, including the sex chromosomes, have been sequenced by scientists.

Credit : Wikipedia 

Picture Credit : Google

Freakish wonders of the universe

The universe is full of deep mysteries and even the fraction of what we know is too fascinating for words. This month let’s take a look at some of the amazing yet scary inhabitants out there.

I’m coming to visit you

Black holes form when huge stars collapse and grow, taking up other objects around them. Think of them as giant invisible blenders that can tear apart planets even thousands of miles away. There aren’t black holes anywhere close to our solar system, but did you know that they can actually travel through space? And scarier still, rapidly-moving black holes cannot be detected! Scientists have assured us that space is a big place and black holes are quite rare – so sit back and relax!

A big show off!

Ever heard of gamma ray bursts? Well, they are considered as the brightest electromagnetic events to occur in the universe, so much so, that they can be seen billions of miles away! Are you also wondering how powerful they are? Apparently they emit as much energy in a few seconds that our sun can in 10 billion years! We’re glad that, like black holes, they are rare and far, far away from us.

Lone travellers

We imagine planets going around a star, endlessly orbiting it as long as they live. It turns out that not all planets exist this way. Astronomers have discovered a few Jupiter-sized planets drifting alone, without a place to call home or a star as a boss. They are thought to have been ejected out of their star system due to some massive explosion event. As long as they are not on a trajectory towards Earth, it’s dreamy fun to think about these lonely nomadic travellers.

What a blast!

Earth is like a magnet but its magnetic field is quite weak; an MRI machine can produce a magnetic field thousand times stronger. Since we can put our head in through the MRI machine, we can obviously put up with that magnetic field. But imagine a magnetic field that is a trillion times stronger than that of Earth. That’s the kind of power that a magnetar possesses! Come within 1000 kilometres of a magnetar and the very molecules that make you up can dissolve! Here’s a fun fact to freak you out in 2004, a magnetar located halfway across the Milky Way (500 quadrillion kilometres away) quaked and its effect was felt on the Earth’s upper atmosphere!

Mission Impossible

What if you stepped too close to a black hole but not quite? That’s exactly what hypervelocity stars did! They bolted away from the black hole at superfast speed. Hypervelocity stars were originally binary stars, of which one was captured and gobbled up by the black hole at the centre of our galaxy while the other lucky star was sent rocketing off at a very high speed, obviously very, very glad to escape.

Picture Credit : Google 

WHY DOES THE SUN RISE IN THE EAST?

Because Earth is spinning eastwards, the Sun comes up from the ground in the east, and sinks in the west.

Most people know that the Sun “rises in the east and sets in the west”. However, most people don’t realize that is a generalization. Actually, the Sun only rises due east and sets due west on 2 days of the year — the spring and fall equinoxes! On other days, the Sun rises either north or south of “due east” and sets north or south of “due west.”

Each day the rising and setting points change slightly. At the summer solstice, the Sun rises as far to the northeast as it ever does, and sets as far to the northwest. Every day after that, the Sun rises a tiny bit further south.

At the fall equinox, the Sun rises due east and sets due west. It continues on it’s journey southward until, at the winter solstice, the Sun rises are far to the south as it ever does, and sets as far to the southwest.

Many, if not most, prehistoric cultures tracked these rising and settings points with great detail. If they had jagged mountains along the horizon, the exact points could be readily remembered. Without a suitably interesting horizon, standing stones could be arranged to line up with the various rising and setting points. Or, tree poles could replace the standing stones. Or, rock cairns could be used.

Credit: Stanford Solar Centre

Picture credit: Google

What is nebula?

A nebula is a formation in space which is constituted mostly of helium, dust, and other gases in various concentrations. The shape and size of a nebula varies, and as such there can be various types of formations having different sizes. Very often, they are huge in size, and their diameters can be a number of light years across. It is derived from Latin, and as such means a cloud. Nebulae exist in the space between the stars—also known as interstellar space. The closest known nebula to Earth is called the Helix Nebula. It is the remnant of a dying star—possibly one like the Sun. It is approximately 700 light-years away from Earth.

It is not clear how exactly a nebula is formed, but it is believed that they are formed by the collapsing of interstellar medium, which then come together because of the gravitational pull of the particles. Nebula is an important object for observation by researchers, who derive significant information about the formation process of stars and planets. A nebula is capable of exerting a gravitational pull, and the force is derived from the particles which come together to form the nebula. With more particles coming together, not only does the nebula increase in proportion, but its gravitational pull also gathers more power and intensity. A nebula is also believed to be one of the primary stages in the formation of stars. Scientists are of the opinion that a nebula can be used to create a trajectory of stellar evolution. There are various nebulae that are in existence at present, though numerous others may exist in the far-flung corners of space that remain to be observed. Some of the most popular ones are Pelican, Crab, Eagle, and Ring Nebula, with Ring being among the most observed ones on the planet.

Credit : Economic Times

Picture Credit : Google