APOD: The Long Tails of Comet NEOWISE (2020 Jul 16)

[APOD Robot]

The Long Tails of Comet NEOWISE

Explanation: This Comet NEOWISE (C/2020 F3) now sweeps through our fair planet's northern skies. Its long tails stretch across this deep skyview from Suchy Vrch, Czech Republic. Recorded on the night of July 13/14, the composite of untracked foreground and tracked and filtered sky exposures teases out details in the comet's tail not visible to the unaided eye. Faint structures extend to the top of the frame, over 20 degrees from the comet's bright coma. Pushed out by the pressure of sunlight itself, the broad curve of the comet's yellowish dust tail is easy to see by eye. But the fainter, more bluish tail is separate from the reflective comet dust. The fainter tail is an ion tail, formed as ions from the cometary coma are dragged outward by magnetic fields in the solar wind and fluoresce in the sunlight. Outbound NEOWISE is climbing higher in northern evening skies, coming closest to Earth on July 23rd.

<< Previous APOD

This Day in APOD

Next APOD >>

[Ann]

Beautiful, Petr Horalek! Comet NEOWISE really looks a lot like comet Hale-Bopp in your picture!

Comet NEOWISE. Photo: Petr Horalek.

---

Comet Hale-Bopp. Photo: Sebastian Voltmer.

---

[Avent]

In times before us comets were told to be omens of great negativity for humanity. I wait for the day this harbeger fades from existence. Remember the days of sunspots. And Pluto was more than a cold orb in space.

[Avent]

Harbinger* auto correct into Oblivion

[neufer]

<<By early July, Comet NEOWISE had brightened to magnitude −1, far exceeding the brightness attained by C/2020 F8 (SWAN), and had developed a second tail. The first tail is blue and made of gas and ions;. There is also a red separation in the tail caused by high amounts of sodium. The second tail is a golden color and is made of dust, like the tail of Comet Hale–Bopp. On July 13, 2020, a sodium tail was confirmed by the Planetary Science Institute's Input/Output facility. Sodium tails have only been observed in very bright comets like Hale–Bopp and sungrazer C/2012 S1 (ISON).

From the infrared signature Joseph Masiero estimates the diameter of the comet nucleus to be approximately 5 km. The nucleus is similar in size to many short-period comets such as 2P/Encke, 7P/Pons-Winnecke, 8P/Tuttle, 14P/Wolf, and 19P/Borrelly.>>

`Mine is a long and a sad tale!’ said the Mouse, turning to Alice, and sighing.

`It IS a long tail, certainly,’ said Alice, looking down with wonder at the Mouse’s tail;
`but why do you call it sad?’

<<Because of its importance in human health, salt has long been an important commodity, as shown by the English word salary, which derives from salarium, the wafers of salt sometimes given to Roman soldiers along with their other wages. In medieval Europe, a compound of sodium with the Latin name of sodanum was used as a headache remedy. The name sodium is thought to originate from the Arabic suda, meaning headache, as the headache-alleviating properties of sodium carbonate or soda were well known in early times. Although sodium, sometimes called soda, had long been recognized in compounds, the metal itself was not isolated until 1807 by Sir Humphry Davy through the electrolysis of sodium hydroxide. In 1809, the German physicist and chemist Ludwig Wilhelm Gilbert proposed the names Natronium for Humphry Davy's "sodium" and Kalium for Davy's "potassium". The chemical abbreviation for sodium was first published in 1814 by Jöns Jakob Berzelius in his system of atomic symbols, and is an abbreviation of the element's New Latin name natrium, which refers to the Egyptian natron, a natural mineral salt mainly consisting of hydrated sodium carbonate.>>

[orin stepanek]

LIKE A BEACON IN THE SKIES!

[neufer]

Harbinger* auto correct into Oblivion

Oblivion (n.) late 14c., oblivioun, "state or fact of forgetting, forgetfulness, loss of memory," from Old French oblivion (13c.) and directly from Latin oblivionem (nominative oblivio) "forgetfulness; a being forgotten," from oblivisci (past participle oblitus) "forget," which is of uncertain origin.

Perhaps originally "even out, smooth over, efface," from ob "over" (see ob-) + root of levis "smooth," also "rubbed smooth, ground down," from PIE *lei-w-, from root *(s)lei- "slime, slimy, sticky"; compare obliterate. But de Vaan and others find that "a semantic shift from 'to be smooth' to 'to forget' is not very convincing." However no better explanation has emerged.

Meaning "state or condition of being forgotten or lost to memory" is from early 15c. In English history, the Acts of Oblivion use the word in the sense of "intentional overlooking" (1610s), especially of political offenses.

Oblivion is the state into which a thing passes when it is thoroughly and finally forgotten. ... Forgetfulness is a quality of a person: as a man remarkable for his forgetfulness. ... Obliviousness stands for a sort of negative act, a complete failure to remember: as a person's obliviousness of the proprieties of an occasion. [Century Dictionary]

.........................................................................
Troilus and Cressida : Act III, scene III

ULYSSES: Time hath, my lord, a wallet at his back,

• Wherein he puts alms for oblivion,

Harbinger (n.) late 15c., herbengar "one sent ahead to arrange lodgings" (for a monarch, an army, etc.), alteration of Middle English herberger "provider of shelter, innkeeper" (late 12c.), from Old French herbergeor "one who offers lodging, innkeeper," agent noun from herbergier "provide lodging," from herber "lodging, shelter," from Frankish *heriberga "lodging, inn" (cognate with Old Saxon, Old High German heriberga "army shelter"), from Germanic compound *harja-bergaz "shelter, lodgings," which is also the source of harbor (n.).

Sense of "forerunner, that which precedes and gives notice of the coming of another" is mid-16c. The unetymological -n- is from 15c. (see messenger).

.........................................................................
Hamlet : Act I, scene I

HORATIO: A mote it is to trouble the mind's eye.

• In the most high and palmy state of Rome,
  A little ere the mightiest Julius fell,
  The graves stood tenantless and the sheeted dead
  Did squeak and gibber in the Roman streets:
  As stars with trains of fire and dews of blood,
  Disasters in the sun; and the moist star
  Upon whose influence Neptune's empire stands
  Was sick almost to doomsday with eclipse:
  And even the like precurse of fierce events,
  As harbingers preceding still the fates
  And prologue to the omen coming on,
  Have heaven and earth together demonstrated
  Unto our climatures and countrymen.--
  But soft, behold! lo, where it comes again!

[Sa Ji Tario]

In this image you can see the tails that the comet unfolds. The dust tail points the orbital path, leaves a trail where it passed and the ion tail is what fixes the wind and the solar magnetic field and propels it into space in a straight line and in opposition, more than 300 generations of humans will pass through before its return to the center of the Solar System and successfully confirmed to Earth very changed or empty of them and with insects as witnesses.-

[Ann]

<<By early July, Comet NEOWISE had brightened to magnitude −1, far exceeding the brightness attained by C/2020 F8 (SWAN), and had developed a second tail. The first tail is blue and made of gas and ions;. There is also a red separation in the tail caused by high amounts of sodium. The second tail is a golden color and is made of dust, like the tail of Comet Hale–Bopp. On July 13, 2020, a sodium tail was confirmed by the Planetary Science Institute's Input/Output facility. Sodium tails have only been observed in very bright comets like Hale–Bopp and sungrazer C/2012 S1 (ISON).

What red separation is that? In which tail?

The chemical abbreviation for sodium was first published in 1814 by Jöns Jakob Berzelius in his system of atomic symbols, and is an abbreviation of the element's New Latin name natrium, which refers to the Egyptian natron, a natural mineral salt mainly consisting of hydrated sodium carbonate.>>

Click to view full size image

From Sweden!

[johnnydeep]

<<By early July, Comet NEOWISE had brightened to magnitude −1, far exceeding the brightness attained by C/2020 F8 (SWAN), and had developed a second tail. The first tail is blue and made of gas and ions;. There is also a red separation in the tail caused by high amounts of sodium. The second tail is a golden color and is made of dust, like the tail of Comet Hale–Bopp. On July 13, 2020, a sodium tail was confirmed by the Planetary Science Institute's Input/Output facility. Sodium tails have only been observed in very bright comets like Hale–Bopp and sungrazer C/2012 S1 (ISON).

What red separation is that? In which tail?

Even after reading the link pointed to by the wikipedia NEOWISE article note I'm not sure. See https://psi.edu/news/neowisesodiumtail. Based on the images there it looks like maybe the "red separation" is part of the ion tail, but the page doesn't even mention any "red separation"

[neufer]

<<By early July, Comet NEOWISE had brightened to magnitude −1, far exceeding the brightness attained by C/2020 F8 (SWAN), and had developed a second tail. The first tail is blue and made of gas and ions;. There is also a red separation in the tail caused by high amounts of sodium. The second tail is a golden color and is made of dust, like the tail of Comet Hale–Bopp. On July 13, 2020, a sodium tail was confirmed by the Planetary Science Institute's Input/Output facility. Sodium tails have only been observed in very bright comets like Hale–Bopp and sungrazer C/2012 S1 (ISON).

What red separation is that? In which tail?

• Beats me... I'm just glad I got an explanation for the easier to see yellowish dust tail.

Explanation: Pushed out by the pressure of sunlight itself,
the broad curve of the comet's yellowish dust tail is easy to see by eye.

[Avent]

Nice to see someone get my point.