“Do not believe what your teacher tells you merelyout of respect for the teacher.”

Gautama Buddha02 KNOWLEDGEPEDIA

M Y S T E R I E S O F

The Universe has fascinated us since we first set our sight onthe night sky. Although our curiosity has pushed us to solvesome of the biggest puzzles in cosmology, we still have a lotto learn. So let’s take a step into the mysterious world...

How will theUniverse end?

Are there ‘Infinite Universes’?

Everything has a beginning and anend — including our universe.Scientists have outlined the threemost prominent ways in which theUniverse might end. They’re calledBig Freeze, Big Crunch and Big Rip.

BIG FREEZE: As the Universe contin-ues to expand at an ever-increasingspeed, the heat is dispersedthroughout space. Eventually thetemperature across Universe willdrop to freezing point.

BIG CRUNCH: According to this theo-ry, billions of years from now theUniverse will cease to expand. Whenthis happens, gravity will become adominant force. This will cause theUniverse to shrink, making all thegalaxies collide with each other.Eventually, all the matter will bepulled together into a super densestate — like a black hole.

BIG RIP: This theory claims that theUniverse will continue to expand untilthe galaxies, stars, planets, and mat-ter are no longer able to hold them-selves together, at which point theyrip apart.

Astronomers know only about the 4per cent of the Universe that is visibleto us in the form of planets,stars, asteroids andother celestial bod-ies. The other 96per cent is madeof substance sci-entists can’t see,detect or evencomprehend. Thisinvisible stuff isdivided into two parts:Dark energy (74%) andDark Matter (22%). Darkenergy is the reason behind the expan-sion of the Universe at an acceleratingrate. Scientists have no clue about howDark energy works or why it exists,

they are only certain that it’s counter-acting gravity and causing the uni-

verse to accelerate in itsexpansion. Dark matter is

thought to be the“glue” that holdsgalaxies together. Itcomprised bizarreingredients thatneither emit nor

absorb light. So howdo we know it exists?

Astronomers detect itspresence by understanding

the behaviour of stars andgalaxies which appear to react to itspresence. But just like dark energy, weknow its effects but are ignorantabout how it works.

What’s Dark Energy and Dark Matter? In the summer of 1950, physicist Enrico Fermi poseda simple question to his colleagues over lunch: “Whereis everybody?” Fermi was referring to alien life in theuniverse. Arguably, he said, in the 4.4 billion years ittook for intelligent life to evolve on our planet, therest of our galaxy should have been overrun withsimilarly smart, technologically advanced aliens.But despite decades of searching the Milky Wayfor signs of extraterrestrials, we haven’t foundanything or anyone. Scientists have offered myr-iad potential answers to the question, even say-ing that aliens are hibernatingor deliberating hiding fromus. Some researchers havealso suggested that high-ly advanced technologi-cal civilisations destroythemselves beforethey have the oppor-tunity to get in con-tact with other in-telligent life in theuniverse.

The parallel universe theory was first proposed in 1950 byUS physicist Hugh Everett. According to this theory, everytime a new physical possibility is explored, the universesplits. Given a number of possible alternative outcomes,each one is played out in its own universe. A motorist whoalmost meets with an accident, for instance, might feel re-lieved at his lucky escape. But in a parallel universe in an-other version, the same driver would have been killed. Yetanother universe will see the motorist recover after treat-ment in hospital. The number of alternative scenarios isendless. A parallel universe is similar, and possibly, even aduplicate of our own universe. There are human beings whomay be exact duplicates of ourselves and are connected tous through mechanisms only explainable using quantumphysics concepts.

Is water vital for life?All life forms on Earth require water for growth andreproduction. But can life flourish on planets withoutwater? Scientists from Cornell University in New Yorkhave proposed a newtype of life that cansurvive on liquid methane ratherthan water. According to them, the bestbet of finding such a life form is on Titan,the giant moon of Saturn. Titan is awashwith seas not of water, but liquid methane.Its surface temperature is minus 180 degreesCelsius. This means that methane-based life cansurvive on chilly and waterless environment.However, the cold temperatures in which liquidmethane exists would produce sluggish lifeform. But it may also imply that more placesare habitable than we thought.

How did life on Earth begin?It’s one of the most fundamental questions of all time,and yet we don’t have a scientific answer for it. Some sci-entists believe that life was carried here on comets or as-teroids. It’s a good theory because we’ve found organicmaterial on some of them. Others think that a piece ofMars could have landed on Earth and allowed life to getstarted. Others think simple molecules caused chemicalreactions to happen that eventually formed more com-plex molecules. Those molecules combined into thingslike RNA, one of the necessary ingredients for life. Thenmulticellular organisms evolved. The deep-sea vent the-ory suggests that life may have begun with submarinehydrothermal vents spewing key hydrogen-rich mole-cules. Their rocky nooks could then have concentratedthese molecules together and provided mineral catalystsfor critical reactions.

74%DARK ENERGY DARK MATTER

STARS, PLANETS,ASTEROIDS etc

22%

4%

How did the moon form? A popular theory is that it result-ed from a huge collision of a Mars-sized celestial body, with Earth,early in our Solar System's histo-ry. Scientists call this imaginedplanet Theia after the deity whogave birth to the moon goddess inancient Greek mythology. Thecrash caused debris from both ce-lestial bodies to orbit Earth — thena ball of partly molten rock ratherthan the solid orb we know today— and eventually coalesce to cre-ate the moon. Although this is themost popular theory, it is not with-out its challenges. Most models sug-gest that more than 60 per cent ofthe moon should be made up of ma-terial from Theia. But rock sam-ples from the Apollo missions sug-gest otherwise.

Photo:Getty Images

Photo: Getty ImagesPhoto: Getty Images

Photo: Getty Images

Photo: Getty Images

Photo: Getty Images

Photo: Getty Images

Photo: Getty Images

Photo: AFP

Could black holes be portals toother universes?Nothing in outer space elicits more awe and fascination than blackholes. They are objects of extreme density, with such strong gravitation-al pull that even light cannot escape from their grasp if it reaches itsevent horizon—the point of no return. Because no light can get out, wecan’t see black holes. They are invisible. Astronomers detect them byobserving how matter swirls around them. Only stars with more than 20times the mass of the Sun will become black holes. Many scientistsincluding physicist Stephen Hawking claim black holes are portals toanother universe. But it will be too premature to accept such a conclu-sion The incredibly strong gravitational field inside would tear apartevery atom in your body. Of course, there is no conclusive evidence tosuggest that black holes are a window to another Universe. Although noblack hole is close enough to Earth to pull the planet to its doom, thereare so many black holes in the universe that counting them is impossi-ble. Nearly every galaxy — our own Milky Way, as well as the 100 billionor so other galaxies visible from Earth — shows signs of a supermassiveblack hole in its centre. Moreover the bigger a galaxy, the more massiveits central black hole. Why? No one has the answer.

How are galaxies formed?As you know, a galaxy is a huge collection of gas, dust, and billions ofstars and their solar systems. Ever wonder how these giant intricatestructures are formed? There are two leading theories to explain howthe first galaxies were created. After the Big Bang, space was made upalmost entirely of hydrogen and helium. Astronomers believe over timegravity pulled dust and gas to form individual stars. These stars slowlyformed a cluster that ultimately became galaxies. Others theorise thatthe early universe disintegrated first into colossal “clumps” that con-tained enough building materials to make galaxies. Do you know that thegalaxy-formation process is still on? Occasionally, galaxies even collidewith each other, merging their stars and dust together. In fact, ourgalaxy, The Milky Way, may contain the remains of several smallergalaxies that it has cannibalised during its lifetime.

Is there anybody out there?

M Y S T E R I E S O F