Entanglement

Quantum mechanics is the science of subatomic particles—the building blocks of matter, including ourselves. It is one of the pillars of the 20th century scientific thinking and one of the most successful quantitative theories of nature.

Quantum mechanics concerns with the principles that describes the interaction of matter and energy in the atomic and subatomic level where the laws of classical Newtonian physics break down completely. Developed during the start of the twentieth century, quantum mechanics is the quintessential tool for calculating and predicting the results of a vast number of experiments and in creating new and advanced technologies based on the insight it provides into the behavior of atomic objects. Much of today’s information technology is possible because of quantum mechanics. It is the underlying principle for many of today’s devices, from lasers, transistors, to charge-coupled devices (CCD), to name a few. “Quantum mechanics was instrumental in predicting antimatter, understanding radioactivity (leading to nuclear power), accounting for the behavior of materials such as semiconductors, explaining superconductivity, and describing interactions such as those between light and matter (leading to the invention of the laser) and of radio waves and nuclei (leading to magnetic resonance imaging)” (Tegmark & Wheeler, 2001, p. 75). And despite of scrutiny of innumerable experiments involving “light, atoms, molecules, and solids, as well as nuclei, electrons, and other subatomic particles”, no violation of quantum mechanics has ever been detected.

As we will see later in this article, this is just the tip of the iceberg.

Are We Alone?

Humankind’s Search for Extra-terrestrial Civilizations

1. INTRODUCTION

Sometimes I think we’re alone in the Universe, and sometimes I think we’re not. In either case the idea is quite staggering.

— Attributed to Arthur C. Clarke, celebrated science and science fiction writer, futurist, and inventor

On December 16, 2014, in the Fall Meeting of the American Geophysical Union in San Francisco, scientists announced that NASA’s Curiosity rover detected sudden spikes of methane in the Martian atmosphere. The scientists also confirmed for the first time the presence of carbon-based organic molecules in a Martian rock sample.

Why is this newsworthy?

Because this could indicate that a carbon based life-form could have existed on the Red Planet at some point during its cosmic evolution. This is also a clue that Mars may currently harbor life, possibly in a microbial form. Life as we know it on Earth, produces significant amounts of methane, thus the spikes in methane in the Martian atmosphere may signal a similar form of life on the planet. However, since methane can also be produced by geological means, the detection of methane is not directly indicative of signs of past or present life forms. Rather, it suggests the possibility that Mars once had the ingredients required for life, and might still harbor them—one only needs to know where to look. The origin of Mars’ methane has become an active area of research with missions such as Curiosity and India’s Mars Orbiter keenly measuring the changes in its abundance.

On the other hand, the answer to the question of whether intelligent life exists somewhere in the Universe is still unknown. Humankind has long been intrigued by the idea of whether life on Earth is unique in the vastness of space, or whether our Galaxy is swarming with extraterrestrial civilizations.

Today, most scientists believe that advanced life forms exist somewhere else in the Universe: In a documentary series, the famous British astrophysicist Stephen Hawking argued that it is ‘perfectly rational’ to assume intelligent life exists elsewhere in the Universe. Hawking believes that primitive life is very common but intelligent life is probably fairly rare.

The Quest for Cosmic Inflation

2014 is the 50th anniversary of the discovery of the Cosmic Microwave Background (CMB). Discovered accidentally in 1964 by two scientists from Bell Laboratories in New Jersey, Arno Penzias and Robert Wilson, who initially thought that the interference was caused by pigeon droppings on their antenna, CMB is a faint glow that permeates the entire universe, dating back to just 380,000 years after the Big Bang. Earlier, the baby universe was too hot and dense for light to travel far without interfering with matter 1 but when it cooled to the point that neutral atoms could form, light could travel through space unimpeded, giving rise to the CMB. Eventually, it was realized Penzias and Wilson had found an imprint from the primordial universe, a discovery that won them the 1978 Nobel Prize in Physics.

It is hard to imagine that this seemingly innocuous discovery would one day become the pillar of modern observational astronomy. This article describes the journey that began fifty years ago with the discovery of CMB by Penzias and Wilson until now, when a group of scientists in the USA, by studying fluctuations in swirls of polarized light in the CMB, unearthed possible evidence that the Big Bang 2, 3 had indeed happened 13.82 billion years ago. In order to follow the progression of ideas in these fifty years, one must start at the very beginning, the Big Bang.


1 Neutral hydrogen formed about 380,000 years after the Big Bang. Prior to this time, the constant interaction between matter (electrons) and light (photons) made the universe opaque.

2 Specifically, the researchers of the Background Imaging of Cosmic Extragalactic Polarization 2 (BICEP2) experiment found evidence of inflation that caused the early universe to expand exponentially for a very short period of time. Inflation cosmology, or simply inflation, is the subject of Section 6.

3 BICEP2’s results were recently challenged by other groups. See here for details.