"Segala sesuatu yang tidak menyertaimu setelah mati, itulah dunia. Harta, jabatan, pujian, bahkan orang yang pernah kita cintai akan tertinggal. Pada akhirnya, kita hanya membawa apa yang melekat pada jiwa, sementara dunia kembali berjalan tanpa kita."
Imam al-Ghazali
The universe’s “shape” refers to the intrinsic curvature of three-dimensional space, not its appearance from somewhere outside it. Positive curvature makes sufficiently large triangles contain more than 180°, while negative curvature makes them contain less.
In flat Euclidean space, the angles sum to 180° and initially parallel paths remain parallel. These geometric rules determine how light and matter travel across cosmic distances.
Measurements of the cosmic microwave background indicate that observable space is extremely close to flat. Curvature alone does not reveal global topology, so a flat universe could still be infinite or wrap around in a finite, connected geometry.
Ini yg dinamai ihtiar mitigasi bencana. Jk tjd tsunami ga perlu lg lari ke gunung atau ke dataran tinggi. Sdh capek duluan blm tentu sampai gunung malah keburu diterjang gelombang tsunami.
What if a particle is not really a particle at all?
String theory proposes that the fundamental objects of nature could be tiny one dimensional strings. Different quantum vibrational states can appear as different particles, while the geometry of extra dimensions helps determine the spectrum we observe.
One striking feature is that closed string theory naturally contains a massless spin 2 state with the properties expected of a graviton. But string theory remains unconfirmed experimentally.
The key idea is simple: the particle may be the vibration, not the string itself.
The hydrogen in your body and present in every molecule of water came from the Big Bang. There are no other appreciable sources of hydrogen in the universe. The carbon in your body was made by nuclear fusion in the interior of stars, as was the oxygen. Much of the iron in your body was made during supernovas of stars that occurred long ago and far away. The gold in your jewelry was likely made from neutron stars during collisions that may have been visible as short-duration gamma-ray bursts or gravitational wave events. Elements like phosphorus and copper are present in our bodies in only small amounts but are essential to the functioning of all known life. The featured periodic table is color coded to indicate humanity's best guess as to the nuclear origin of all known elements. The sites of nuclear creation of some elements, such as copper, are not really well known and are continuing topics of observational and computational research.
Image Credit: NASA's GSFC, SVS
Ever get lost in all those mathematical “spaces”?
This beautiful diagram maps the full hierarchy from the wildest to the most familiar. Topological spaces are defined only by open sets. Metric spaces add distance. Vector spaces allow linear combinations. Normed spaces measure size while inner product spaces add angles.
At the core sits Euclidean R^n, the complete geometry of our everyday world.
Rayleigh scattering makes the sky blue and sunsets red. Air molecules scatter short wavelengths much more strongly, with intensity roughly proportional to 1/λ⁴. At sunset, the longer atmospheric path scatters away more blue, leaving red and orange light.
Light can become matter.
When a sufficiently energetic gamma-ray photon interacts with a nucleus, its energy can produce an electron–positron pair. The nucleus takes up recoil momentum, keeping energy and momentum conserved.
A beautiful example of (E=mc^2) in action.