Astrophysics - the arena where all cosmic events unfold

In science, properties refer to the characteristics that can be used to describe and identify a material or substance. These characteristics can be observed, measured, or tested. Properties help differentiate one material from another and can be either physical or chemical. 

Physical properties are characteristics that can be observed or measured without changing the substance's chemical composition. Examples include: 

1. Color: The visible hue of the substance.
2. Texture: The surface quality of the substance (e.g., rough, smooth).
3. Shape: The three-dimensional form of the substance.
4. Density: The mass per unit volume.
5. Hardness: The resistance to scratching or indentation.
6. Melting point: The temperature at which a substance changes from solid to liquid.
7. Boiling point: The temperature at which a substance changes from liquid to gas.

Chemical properties describe how a substance interacts with other substances or changes during a chemical reaction. Examples include: 

1. Reactivity: How readily a substance combines with other substances.
2. Flammability: The ability of a substance to burn.
3. Acidity/Basicity (pH): A measure of a substance's acidity or alkalinity.

Space is not just empty; it's the arena where all cosmic events unfold. It's the volume that contains everything we observe in the universe.  

Space: In astrophysics, space refers to the vast, three-dimensional expanse that encompasses all celestial objects and phenomena, including stars, planets, galaxies, and the regions between them. It is often described as a near-vacuum, a boundless region beyond Earth's atmosphere where the majority of the universe's matter and energy reside. 

While often depicted as a perfect vacuum, space contains a mix of particles, radiation, magnetic fields, and other forms of matter and energy.

Black holes are regions in space with immense gravity, so strong that nothing, not even light, can escape. Scientists study them indirectly by observing their effects on surrounding matter and spacetime, using telescopes that detect radiation emitted by matter spiraling into the black hole and by observing how their gravity affects nearby stars and other objects. 

This is a more specific term, often used within the field of astronomy, that focuses on the observational aspects of black holes, such as their detection, their effects on surrounding matter, and their influence on galaxy formation and evolution. 

Black Hole Cosmology: This refers to the specific cosmological model where our observable universe is considered to be the interior of a black hole within a larger parent universe.  

[sight, smell, hearing, taste and touch]

[vestibular and proprioception - connected to the tactile sense (touch)]

Vestibular sense involves movement and balance. It is the sense of where our body is in space. Close your eyes for a minute and take a quick inventory of your body. Even without seeing or touching, you know where your arms and legs are in space. Vestibular sense is important because it helps us stand, walk and sit up without falling over.

Proprioception is also called body awareness sense. This sense helps us understand where our body parts are in relation to each other. It also helps us figure out how much force to use in different activities (think of picking up a fragile glass versus a gallon of milk).

No, smells do not have a wavelength in the way that light or sound do. Instead, smells are caused by the interaction of volatile molecules with receptors in the nose. These molecules, rather than being part of an electromagnetic or sound wave, are physically detected and interpreted by the olfactory system. 

No, taste itself does not have a frequency or wave like sound or light. Taste is a chemical sense, and the perception of taste is triggered by molecules binding to receptors on taste buds. These receptors then send electrical signals to the brain, which interprets these signals as different tastes. While some studies explore the relationship between taste perception and vibrations or frequencies, these are not inherent properties of taste itself. 

Electrical signals in the human body, like nerve impulses, travel at varying frequencies depending on the specific process. Nerve impulses typically travel at frequencies up to 1000 Hz (1 kHz), with maximum firing rates for neurons reaching 500 Hz, though some cell types can reach 1000 Hz. Brain waves, measured by EEG, range from very slow (1 Hz) during sleep to faster frequencies like beta (13-25 Hz) and gamma (25-60 Hz) during cognitive activity, with some brain wave frequencies exceeding 100 Hz. 

Frequencies below 1 Hz are considered sub-hertz. For example, a 0.1 Hz signal completes one cycle every 10 seconds. 

sound - needs a medium

0.1 Hz - one cycle every 10 seconds.

1 Hz - 1 cycle every second

1 Hz - Rats and mice (1-90 kHz)

2 Hz - Lower audio limit for dolphins

16 Hz - Lower audio limit for elephants

20 Hz - Lower audio limit for humans / Audio floor. Animals like rhinos and hippos hear low-frequency sounds, which are effective for long-distance communication.

40 Hz - Wolves and Dogs

45 Hz - Cats

55 Hz - Horses

200 Hz - Owls

360 Hz - Rabbits

12 kHz - Elephants and Owls

20 kHz - Upper audio limit for humans / Audio ceiling. Dogs and cats, for example, hear higher frequencies than humans, which is advantageous for hunting and detecting prey.

33 kHz - Horses

42 kHz - Rabbits

45 kHz - Dogs

80 kHz - Wolves

85 kHz - cats (45-85 kHz)

90 kHz - Rats and mice (1-90 kHz)

150 kHz - dolphins can hear up to 150 kHz  

200 kHz - bats can hear up to 200 kHz

300 kHz - greater wax moth can hear sounds up to 300 kHz

electromagnetic - doesn't need a medium

0.5–4 Hz - Delta (δ) - Sleep

4–8 Hz - Theta (θ) - Deeply relaxed, inward focused

8–12 Hz - Alpha (α) - Very relaxed, passive attention

Low beta waves. These range from 12 to 15 Hertz and occur when you’re thinking.

Beta waves. These range from 15 to 22 Hertz and occur when you’re performing activities or focusing on something.

14 - 30 Hz - Binaural beats in the beta frequencies (14 to 30 Hz) have been linked to increased concentration and alertness, problem-solving, and improved memory.

High beta waves. These range from 22 to 38 Hertz. They occur when you’re excited or anxious. They also occur when you experience something new or have complex thoughts. 

12–35 Hz - Beta (β) - Anxiety dominant, active, external attention, relaxed

30 - 80 Hz - Gamma brain waves. Gamma waves are the fastest brain waves. They mainly occur when you’re highly alert and conscious. They range from 30 to 80 Hertz.