APOD: How to Identify that Light in the Sky (2024 Jun 09)

[APOD Robot]

How to Identify that Light in the Sky

Explanation: What is that light in the sky? The answer to one of humanity's more common questions may emerge from a few quick observations. For example -- is it moving or blinking? If so, and if you live near a city, the answer is typically an airplane, since planes are so numerous and so few stars and satellites are bright enough to be seen over the glare of artificial city lights. If not, and if you live far from a city, that bright light is likely a planet such as Venus or Mars -- the former of which is constrained to appear near the horizon just before dawn or after dusk. Sometimes the low apparent motion of a distant airplane near the horizon makes it hard to tell from a bright planet, but even this can usually be discerned by the plane's motion over a few minutes. Still unsure? The featured chart gives a sometimes-humorous but mostly-accurate assessment. Dedicated sky enthusiasts will likely note -- and are encouraged to provide -- polite corrections.

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[habib.chehade@gmail.com]

The UFOs are missing !
The answer : UFO should come as:
Is it really big? --> No -->Is it Moving? -->Yes-->So quickly you almost missed it? --> Yes --> Is it extra super bright --> No --> Is it rotating? -->Yes (UFO) ; NO (Meteor)

[Rauf]

A polite correction here:
As this chart is dated, I think it needs an update which adds Tiangong, as the ISS is no longer the only space station which is home to astronauts!

[Christian G.]

Another one: If it's blinking but appears too high to be an aircraft, or even more mystifying, if the blinking is irregular! - it's a tumbling satellite.

[divad27182]

Starting at "Bolide":

Are there more?
No: Bolide
Yes: Fireworks

[Capt. Obvious]

Polite correction:
Instead of Astronauts waving (cannot actually see them), try "Is it going straight?"
Yes - Satellite or ISS. No - UFO.

[stargazer2024]

With the rise in launches from various countries over the last 20 yrs or so, some parts of the world are now treated to the sight of failed boosters and/or 3rd stages in the night sky.

[wilddouglascounty]

Or in certain parts of eastern Europe/Middle East: exploding alternative to bolide could be a missile shot down by defensive missile

[MevetS]

My first thought upon seeing today's APOD was that this is one of Randall Munroe's XKCD comics, as he often uses flowcharts to humorous effect. Here's an example: https://xkcd.com/1688/

It made me think of this one: https://xkcd.com/2633/

[florid_snow]

Another one: If it's blinking but appears too high to be an aircraft, or even more mystifying, if the blinking is irregular! - it's a tumbling satellite.

Yep, and slow but steady brightness changes would likely be the giant tumbling rocket body stage left in orbit after releasing a satellite, I saw one of those recently, very beautiful the way it slowly dims and brightens up again.

[Roy]

Interesting to see how other languages use diacritical marks on Roman letters to indicate sounds that would otherwise require an invented letter. Of course, English is replete with spellings left over from the monks trying to spell Old English sounds which have since gone silent. Example - knight; the German cognate “knecht” has all letters pronounced.

[Chris Peterson]

Interesting to see how other languages use diacritical marks on Roman letters to indicate sounds that would otherwise require an invented letter. Of course, English is replete with spellings left over from the monks trying to spell Old English sounds which have since gone silent. Example - knight; the German cognate “knecht” has all letters pronounced.

Almost. The "ch" in German is a digraph just like the "gh" in English.

[johnnydeep]

Does anyone else see it? No - you might be hallucinating, or having a brain aneurysm.

[Ann]

Interesting to see how other languages use diacritical marks on Roman letters to indicate sounds that would otherwise require an invented letter. Of course, English is replete with spellings left over from the monks trying to spell Old English sounds which have since gone silent. Example - knight; the German cognate “knecht” has all letters pronounced.

Almost. The "ch" in German is a digraph just like the "gh" in English.

---

Then again, the Swedish "knekt" has all its letters pronounced!

Ann

[lefthip]

Just a word about your APOD translations. You haven't included "Francais" as an option and you have so many Canadiens who love your web site and they also love to spend winters in the shadows of the Cape Canaveral launch site. Must've been an "oversite"!