Tuesday, 26 March 2013

Beberapa Misteri dalam Cosmology dan General Relativity

"Pangkat ukur pupulasan, banda ngan ukur titipan; nyawa ukur gagaduhan. 
Tetela jeung rumasa, manusa tuna kaboga"
 ~Piwuruk Urang Sunda~

Begitu terbatasnya pengetahuan dan kekuatan manusia dalam menguak tabir rahasia alam semesta raya, kita adalah makhluk yang lemah. 

Masih terdapat ribuan bahkan juta'an ketidaktahuan kita akan semesta ini.

Penulis mencoba memaparkan beberapa hal yang masih menjadi pertanyaan hingga sekarang dalam bidang Kosmologi dan Relativitas Umum Einstein.

Cosmic inflation
Is the theory of cosmic inflation correct?, and if so, what are the details of this epoch? What is the hypothetical inflaton field giving rise to inflation? If inflation happened at one point, is it self-sustaining through inflation of quantum-mechanical fluctuations, and thus ongoing in some impossibly distant place?
Horizon problem
Why is the distant universe so homogeneous, when the Big Bang theory seems to predict larger measurable anisotropies of the night sky than those observed? Cosmological inflation is generally accepted as the solution, but are other possible explanations such as a variable speed of light more appropriate?
Future of the universe
Is the universe heading towards a Big Freeze, a Big Rip, a Big Crunch or a Big Bounce? Or is it part of an infinitely recurring cyclic model?
 Gravitational wave
Can gravitational waves be detected experimentally?
Baryon asymmetry
Why is there far more matter than antimatter in the observable universe?
Cosmological constant problem
Why does the zero-point energy of the vacuum not cause a large cosmological constant? What cancels it out?
Dark matter
What is dark matter? Is it related to supersymmetry? Is the mass that makes up the dark matter halos around galaxies made up of the lightest form of supersymmetric particle (LSP)? Do the phenomena attributed to dark matter point not to some form of matter but actually to an extension of gravity?

"No guns, no killing"
~The Dark Knight~
Dark energy
What is the cause of the observed accelerated expansion (de Sitter phase) of the Universe? Why is the energy density of the dark energy component of the same magnitude as the density of matter at present when the two evolve quite differently over time; could it be simply that we are observing at exactly the right time? Is dark energy a pure cosmological constant, or are models of quintessence such as phantom energy applicable?
Dark flow
What is the cause of a large swath of galaxy clusters all moving towards one part of the universe?
Ecliptic alignment of CMB anisotropy
Some large features of the microwave sky, at distances of over 13 billion light years, appear to be aligned with both the motion and orientation of the Solar System. Is this due to systematic errors in processing, contamination of results by local effects, or an unexplained violation of the Copernican principle?
Shape of the Universe
What is the 3-manifold of comoving space, i.e., of a comoving spatial section of the Universe, informally called the "shape" of the Universe? Neither the curvature nor the topology is presently known, though the curvature is known to be "close" to zero on observable scales. The cosmic inflation hypothesis suggests that the shape of the Universe may be unmeasurable, but since 2003, Jean-Pierre Luminet et al. and other groups have suggested that the shape of the Universe may be the Poincaré dodecahedral space. Is the shape unmeasurable, the Poincaré space, or another 3-manifold?
"Semoga kami semua dijadikan manusia-manusia yang selalu dapat mengambil hikmah dan kebijaksana'an tatkala merenungi ayat-ayat Semesta-Mu"

Thanks to:

1. Bpk. Dr. rer. nat. Muhammad Farchani Rosyid, M.Sc.
2. Bpk. Dr. rer. nat. L.T. Handoko, M.Sc.
3. Kak Handika Satrio Ramadhan, M.Sc., Ph.D.
4. Kak Khalid Fatmawijaya, S.Si.
5. Kak Iqbal Robiyana, S.Pd.
6. Kang Anton Timur Jaelani, S.Si.


1. http://astrophysicsblogs.blogspot.com/2012/03/unsolved-problems-in-physics-part-i.html
2. Wikipedia
3. http://arxiv.org/

Gaya Nuklir Kuat

Satu tahun yang lalu penulis berkesempatan membahas mengenai gaya-gaya fundamental di alam, yang terdiri dari Gaya Gravitasi, Gaya Elektromagnetik, Gaya Nuklir Kuat dan Gaya Nuklir Lemah, pada kesempatan kali ini kiranya akan dikupas mengenai apa itu gaya nuklir kuat?

GAYA di sini bukan merujuk pada sebuah kata yang amat terkenal dalam kehidupan sehari-hari misalnya:

Wow GAYA banget sich elo? Bukan gaya yang itu.

Penjelasan Gaya dalam Fisika:

In physics, a force is any influence that causes an object to undergo a certain change, either concerning its movement, direction, or geometrical construction. It is measured with the SI unit of newtons and represented by the symbol F. In other words, a force is that which can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate, or which can cause a flexible object to deform. Force can also be described by intuitive concepts such as a push or pull. A force has both magnitude and direction, making it a vector quantity.

Interaksi Kuat atau Gaya Kuat

In particle physics, the strong interaction (also called the strong force, strong nuclear force, or color force) is one of the four fundamental interactions of nature, the others being electromagnetism, the weak interaction and gravitation. At atomic scale, it is about 100 times stronger than electromagnetism, which in turn is orders of magnitude stronger than the weak force interaction and gravitation.

The strong interaction is observable in two areas: on a larger scale (about 1 to 3 femtometers (fm)), it is the force that binds protons and neutrons (nucleons) together to form the nucleus of an atom. On the smaller scale (less than about 0.8 fm, the radius of a nucleon), it is the force (carried by gluons) that holds quarks together to form protons, neutrons and other hadron particles.

In the context of binding protons and neutrons together to form atoms, the strong interaction is called the nuclear force (or residual strong force). In this case, it is the residuum of the strong interaction between the quarks that make up the protons and neutrons. As such, the residual strong interaction obeys a quite different distance-dependent behavior between nucleons, from when it is acting to bind quarks within nucleons. The binding energy related to the residual strong force is used in nuclear power and nuclear weapons.

The strong interaction is thought to be mediated by gluons, acting upon quarks, antiquarks, and other gluons. Gluons, in turn, are thought to interact with quarks and gluons because all carry a type of charge called "color charge." Color charge is analogous to electromagnetic charge, but it comes in three types rather than one, and it results in a different type of force, with different rules of behavior. These rules are detailed in the theory of quantum chromodynamics (QCD), which is the theory of quark-gluon interactions.

Lihat Juga:
 Bacaan Lebih Lanjut:
"Kekuatan dan gaya-gaya di alam sesungguhnya menunjukan Ke-Maha'an Sang Pencipta Semesta Raya Ini"


1. http://astrophysicsblogs.blogspot.com/2012/03/gaya.html
2. Wikipedia
3. Sekolah Sains dan Teknologi Nuklir
5. International Atomic Energy Agency