9 ms·

> a distance of about 79% of an astronomical unit > located about 46% of an AU from its stars Does anyone find it weird that distances are quoted like this, a

> a distance of about 79% of an astronomical unit > located about 46% of an AU from its stars Does anyone find it weird that distances are quoted like this, and not 0.79AU and 0.46AU ? Is this the conventional way to write it?

its_ethan 3y ago
This is definitely weird, it'd be like saying 79% of a meter instead of just 0.79m lol
- dylan604 3y ago
  but it's not wrong though. that's like saying you can't say 20% off and must provide the exact discount in whatever monetary unit you prefer.
  - anentropic 3y ago
    it's not the same if you think about it a bit more an equivalent monetary example would be describing something which costs 79 cents as costing "79% of a dollar" sounds weird no?
    - dylan604 3y ago
      we say half the speed of light, we don't say 149,896,229m/s LHC uses terms like 90% speed of light to be more specific example i guess it all depends on what circles you do or do not float in.
      - anentropic 3y ago
        Equally, we never say "50% of a m/s" instead of "0.5m/s" And notations like 0.9c are also quite commonly used for velocities close to the speed of light (the LHC tends to use TeV more often as a unit, which corresponds to a certain velocity for protons, but they mainly care about the energy) But using percentages with the speed of light makes some sense because it marks one end of an absolute scale, there is no way to go 1.1c or 2.5c. So using a percentage emphasises how close we are to the maximum value. But the same doesn't apply to AU.
        iso1631 3y ago
        0.9AU, 0.9C, 0.9 Parsecs, 0.9 miles, all make sense half an AU, half the speed of light, half a parsec, half a mile, again fine 90% of an AU, 90% of the speed of light, 90% of a parsec, 90% of a mile. That sounds odd.
al_be_back 3y ago
a bit yes - but then again it's a unit Humanized, easier to read, more accessible I guess.
- anentropic 3y ago
  Is it though? I can't think of any other units where we write it like that
  - al_be_back 3y ago
    Energy equals mass times speed of light squared, is the same as: E = mc². The former is more accessible to a general public audience (reader).
    - anentropic 3y ago
      to be clear, I was referring to use of percentages rather than "Astronomical Unit" vs AU I could understand wanting to explain what AU stands for, and what an Astronomical Unit represents, it just seemed weird to then convert everything into percentages as well
      - al_be_back 3y ago
        i agree, it's a bit weird. personally I'd use 0.5 rather than 50% to record the facts, and 50% to make a salient point/summary, since the latter is a higher level of abstraction (perhaps even anthropocentric)
- saiya-jin 3y ago
  I find it hard to believe somebody would know what exactly is AU, yet at the same time struggle with fractions (or whatever is the proper name for it), while being OK with percentages representation of same numbers.
  - dylan604 3y ago
    The whole point on an AU is we don't need to know an exact number. Using human relatable measurements means the numbers get mind numbingly big, fast. Even though the average human doesn't know the exact distance from the earth to the sun in meters and/or feet, they can get a rough sense of "the distance from the earth to the sun". also, at what exact moment are you taking that exact distance in meters/feet? the orbit is not exactly circular, so that radius measurement isn't the same all the time. nor does the average person know the exact radius/diameter of the earth, jupiter, or the sun, but we often see references to the earth is a fraction of jupiter and that the sun is some large number of jupiters.
microtherion 3y ago
In an US source, you can count yourself lucky if the distance is not given in “length of football fields” or “giraffes”.
- OnlyMortal 3y ago
  I’ll just leave this here: https://www.theregister.com/Design/page/reg-standards-converter.html https://www.theregister.com/Design/page/reg-standards-conver...
- phpisthebest 3y ago
  That would be 1,077,047,953.603 football fields, or 387,737,263,297.2403 feet, or 1,163,211,789,891.721 hands Freedom Units are the best units.
  - dylan604 3y ago
    I thought Freedom was measured in calibers.
    - mkaic 3y ago
      My go-to nonsensical sarcastic freedom unit is Bullet Velocities per Football Field
- localplume 3y ago
  but it wouldn't? US astrophysicists and others use units like AU. and if they were using football fields, its to make it so people understand it better. AU is pretty hard to grasp for most people I'd imagine. the writer is American anyway.
aragilar 3y ago
0.79AU and 0.46AU would be the normal way to write it.

its_ethan 3y ago

This is definitely weird, it'd be like saying 79% of a meter instead of just 0.79m lol

dylan604 3y ago
but it's not wrong though. that's like saying you can't say 20% off and must provide the exact discount in whatever monetary unit you prefer.
- anentropic 3y ago
  it's not the same if you think about it a bit more an equivalent monetary example would be describing something which costs 79 cents as costing "79% of a dollar" sounds weird no?
  - dylan604 3y ago
    we say half the speed of light, we don't say 149,896,229m/s LHC uses terms like 90% speed of light to be more specific example i guess it all depends on what circles you do or do not float in.
    - anentropic 3y ago
      Equally, we never say "50% of a m/s" instead of "0.5m/s" And notations like 0.9c are also quite commonly used for velocities close to the speed of light (the LHC tends to use TeV more often as a unit, which corresponds to a certain velocity for protons, but they mainly care about the energy) But using percentages with the speed of light makes some sense because it marks one end of an absolute scale, there is no way to go 1.1c or 2.5c. So using a percentage emphasises how close we are to the maximum value. But the same doesn't apply to AU.
      - iso1631 3y ago
        0.9AU, 0.9C, 0.9 Parsecs, 0.9 miles, all make sense half an AU, half the speed of light, half a parsec, half a mile, again fine 90% of an AU, 90% of the speed of light, 90% of a parsec, 90% of a mile. That sounds odd.

al_be_back 3y ago

a bit yes - but then again it's a unit Humanized, easier to read, more accessible I guess.

anentropic 3y ago
Is it though? I can't think of any other units where we write it like that
- al_be_back 3y ago
  Energy equals mass times speed of light squared, is the same as: E = mc². The former is more accessible to a general public audience (reader).
  - anentropic 3y ago
    to be clear, I was referring to use of percentages rather than "Astronomical Unit" vs AU I could understand wanting to explain what AU stands for, and what an Astronomical Unit represents, it just seemed weird to then convert everything into percentages as well
    - al_be_back 3y ago
      i agree, it's a bit weird. personally I'd use 0.5 rather than 50% to record the facts, and 50% to make a salient point/summary, since the latter is a higher level of abstraction (perhaps even anthropocentric)
saiya-jin 3y ago
I find it hard to believe somebody would know what exactly is AU, yet at the same time struggle with fractions (or whatever is the proper name for it), while being OK with percentages representation of same numbers.
- dylan604 3y ago
  The whole point on an AU is we don't need to know an exact number. Using human relatable measurements means the numbers get mind numbingly big, fast. Even though the average human doesn't know the exact distance from the earth to the sun in meters and/or feet, they can get a rough sense of "the distance from the earth to the sun". also, at what exact moment are you taking that exact distance in meters/feet? the orbit is not exactly circular, so that radius measurement isn't the same all the time. nor does the average person know the exact radius/diameter of the earth, jupiter, or the sun, but we often see references to the earth is a fraction of jupiter and that the sun is some large number of jupiters.

microtherion 3y ago

In an US source, you can count yourself lucky if the distance is not given in “length of football fields” or “giraffes”.

OnlyMortal 3y ago
I’ll just leave this here: https://www.theregister.com/Design/page/reg-standards-converter.html https://www.theregister.com/Design/page/reg-standards-conver...
phpisthebest 3y ago
That would be 1,077,047,953.603 football fields, or 387,737,263,297.2403 feet, or 1,163,211,789,891.721 hands Freedom Units are the best units.
- dylan604 3y ago
  I thought Freedom was measured in calibers.
  - mkaic 3y ago
    My go-to nonsensical sarcastic freedom unit is Bullet Velocities per Football Field
localplume 3y ago
but it wouldn't? US astrophysicists and others use units like AU. and if they were using football fields, its to make it so people understand it better. AU is pretty hard to grasp for most people I'd imagine. the writer is American anyway.

aragilar 3y ago

0.79AU and 0.46AU would be the normal way to write it.