Comet Lovejoy flies into Sun to reveal solar secrets

BBC

A comet's close encounter with the Sun has given scientists a look at a solar region that has never been visited by spacecraft.

In 2011, comet Lovejoy hurtled deep into the Sun's violent atmosphere - an area called the solar corona.

The images reveal the comet getting increasingly bright as it enters the solar corona, where it encounters temperatures of millions of degrees Celsius. Its tail also begins to move.

After comet Lovejoy made its close approach, the scientists were surprised to see the ball of ice and dust survived, re-emerging on the other side of the Sun.

Two days later, though, it disintegrated.

Comets

Long-period comets have highly eccentric orbits and periods ranging from 200 years to thousands or even millions of years.

Lovejoy

Comet Lovejoy, formally designated C/2011 W3 (Lovejoy), is a long-period comet and Kreutz Sungrazer. It was discovered in November 2011

BBC

Comet Ison, which has been called a potential "comet of the Century" because of its size and orbit, will pass by the Earth at the end of the year, before making its way towards the Sun.

Comets Ison will be one to remember that's for sure...

Cool find thought is was worth the read, I find serenity in watching the night sky and pieces like this interest me.

So hard see this meteor ..ison too..so hard to see from my country..

uh...
so a comet... made of ICE... went THROUGH the sun, and came out the other side intact?

...something is seriously wrong either with that story, or with the current theories regarding the sun and how it operates. At the expected temperatures, that thing should have been obliterated long before it ever reached the sun.

Originally posted by Awen24
uh...
so a comet... made of ICE... went THROUGH the sun, and came out the other side intact?

...something is seriously wrong either with that story, or with the current theories regarding the sun and how it operates. At the expected temperatures, that thing should have been obliterated long before it ever reached the sun.

Made of rock and ice, and in some comets there might be more of rock and less of ice. There might also be lots of ice packed deep inside (comets are typically several km in diameter) and only getting out gradually through cracks and pores. Just my theory...

It's also worth noting that comets spend a very short time in such proximity to the Sun.

Lets click on some links in the thread to reveal more information.

Lovejoy

The comet's perihelion took it through the Sun's corona on 16 December 2011, after which it emerged intact and continued on its orbit to the outer Solar System.

Comet Lovejoy reached perihelion on 16 December 2011 at 00:17 UTC, as it passed approximately 140,000 kilometres (87,000 mi) above the Sun's surface[14][15] at a speed of 650 km/s (400 mi/s), or 0.2% the speed of light.[16] It was not expected to survive the encounter due to extreme conditions in the corona, such as temperatures reaching more than one million kelvins and the exposure time of nearly an hour. However, the Solar Dynamics Observatory (SDO), as well as other Sun-monitoring spacecraft, observed the comet emerge from the corona intact.[17][18][19] The STEREO and SOHO spacecraft continued to observe the comet as it moved away from the Sun.[19]

Before perihelion, the nucleus of Comet Lovejoy had been estimated to be between 100 and 200 metres (330 and 660 ft) in diameter. Since the comet survived perihelion, it is thought that the nucleus must have been larger, perhaps up to 500 metres (1,600 ft).[20] During the coronal passage, it is believed that a significant fraction of the comet's mass was burned off.

In the event that some portion of the nucleus did survive, the eccentricity and inclination of Comet Lovejoy's orbit avoids significant perturbation from planets, which leaves the possibility that the comet may return for another perihelion.[8] Using an epoch 2050 solution, Comet Lovejoy is estimated to have about a 622-year orbit and a return to perihelion around the year 2633.[1]

From the BBC article

After comet Lovejoy made its close approach, the scientists were surprised to see the ball of ice and dust survived, re-emerging on the other side of the Sun.

Two days later, though, it disintegrated.

I'm still gonna wait patiently for the show of the millennium with comet Ison.

Okay, lets look at what has been established.

Comet Lovejoy was discovered in Nov. of 2011 and passed through the sun and disintegrated.

It is classified as a long period comet with an estimated orbit of 622 years and estimated, if it had survived to pass again in 2633, meaning that it must have passed 622 years before in 1388 and so on.

Meaning at it's current trajectory, one must conclude as it is a sun grazer it has eroded over time with each passing of the sun and possibly started out much bigger than estimated.

OR,

Newton's laws of motion

First law: An object at rest remains at rest unless acted upon by a force. An object in motion remains in motion, and at a constant velocity, unless acted upon by a force. [2][3]

Second law: The acceleration of a body is directly proportional to, and in the same direction as, the net force acting on the body, and inversely proportional to its mass. Thus, F = ma, where F is the net force acting on the object, m is the mass of the object and a is the acceleration of the object.

Third law: When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction to that of the first body.

Relation to Newton's laws

]Isaac Newton computed in his Philosophiæ Naturalis Principia Mathematica the acceleration of a planet moving according to Kepler's first and second law.

The direction of the acceleration is towards the Sun.

The magnitude of the acceleration is in inverse proportion to the square of the distance from the Sun.

This suggests that the Sun may be the physical cause of the acceleration of planets.

Newton defined the force on a planet to be the product of its mass and the acceleration. (See Newton's laws of motion). So:

Every planet is attracted towards the Sun.

The force on a planet is in direct proportion to the mass of the planet and in inverse proportion to the square of the distance from the Sun.

Here the Sun plays an unsymmetrical part, which is unjustified. So he assumed Newton's law of universal gravitation:

All bodies in the solar system attract one another.

The force between two bodies is in direct proportion to the product of their masses and in inverse proportion to the square of the distance between them.

As the planets have small masses compared to that of the Sun, the orbits conform to Kepler's laws approximately. Newton's model improves upon Kepler's model fits actual observations more accurately. (See two-body problem).

A deviation in the motion of a planet from Kepler's laws due to the gravity of other planets is called a perturbation.

Orbital Period

The anomalistic period is the time that elapses between two passages of an object at its periapsis (in the case of the planets in the solar system, called the perihelion), the point of its closest approach to the attracting body. It differs from the sidereal period because the object's semimajor axis typically advances slowly.

This means Lovejoy perihelion (the sun) is Lovejoy's attracting body.

So it has either passed around the sun multiple times on it's 622 year orbit, or because of the laws of motion, something set it in motion recently which is why it was only discovered in Nov of 2011 and destroyed the following month?

Originally posted by wildespace

Originally posted by Awen24
uh...
so a comet... made of ICE... went THROUGH the sun, and came out the other side intact?

...something is seriously wrong either with that story, or with the current theories regarding the sun and how it operates. At the expected temperatures, that thing should have been obliterated long before it ever reached the sun.

Made of rock and ice, and in some comets there might be more of rock and less of ice. There might also be lots of ice packed deep inside (comets are typically several km in diameter) and only getting out gradually through cracks and pores. Just my theory...

It's also worth noting that comets spend a very short time in such proximity to the Sun.

I was being slightly facetious with my post, but regardless...
meteors etc. that enter our atmosphere burn up, and end up being relatively small compared to their original size by the time they impact (if they impact at all).
I still find it hard to believe that anything made of rock or ice could endure ~5700 degrees kelvin and come out the other side intact. A comet would have to travel the entire 1.392684×10(6) diameter of the sun, not to mention the immense distance in space under which the comet would still be affected by heat.

...still doesn't seem to add up.

[edit] The OP says that the comet entered the solar corona. The corona has an estimated temperature of 1-2 MILLION degrees Kelvin. You honestly think a chunk of space rock could survive that?

Comet Lovejoy reached perihelion on 16 December 2011 at 00:17 UTC, as it passed approximately 140,000 kilometres (87,000 mi) above the Sun's surface[14][15] at a speed of 650 km/s (400 mi/s), or 0.2% the speed of light.[16] It was not expected to survive the encounter due to extreme conditions in the corona, such as temperatures reaching more than one million kelvins and the exposure time of nearly an hour. However, the Solar Dynamics Observatory (SDO), as well as other Sun-monitoring spacecraft, observed the comet emerge from the corona intact.[17][18][19] The STEREO and SOHO spacecraft continued to observe the comet as it moved away from the Sun.[19] Before perihelion, the nucleus of Comet Lovejoy had been estimated to be between 100 and 200 metres (330 and 660 ft) in diameter. Since the comet survived perihelion, it is thought that the nucleus must have been larger, perhaps up to 500 metres (1,600 ft).[20] During the coronal passage, it is believed that a significant fraction of the comet's mass was burned off.[19]

Source

Some things to note: it was moving at about 650 km/s (or 0.2% the speed of light). It was only exposed in the corona for 1 hour. While the corona is 1m K in temperature, it is the corona and not a denser medium. The fact that it survived (barely. it did perish 2 days later) showed that it's original diameter of 200 meters was incorrect, and it was much bigger than originally estimated.

reply to post by Awen24


The very low density of the corona is a big factor. Take our atmosphere for example. Temperature in thermosphere layer (which begins at 85 km above earth) can reach 2,500 °C during the day. But due to the extremely low density of air, you wouldn't feel warm there. It is so near vacuum that there is not enough contact with the few atoms of gas to transfer much heat. en.wikipedia.org...

Any one happen to catch the contrast in reports? BBC by Rebecca Morelle on 6 June 2013

You have a BBC article with Dr Schrijver stating "Dr Schrijver said: "There have been about 1,600 Sun-grazing comets observed. But all of them vanished and none came out. It's the first one we have seen that was large enough to survive close passage - although not for very long."

The comet's perihelion took it through the Sun's corona on 16 December 2011, after which it emerged intact and continued on its orbit to the outer Solar System.

The STEREO and SOHO spacecraft continued to observe the comet as it moved away from the Sun.[19]

Before perihelion, the nucleus of Comet Lovejoy had been estimated to be between 100 and 200 metres (330 and 660 ft) in diameter. Since the comet survived perihelion, it is thought that the nucleus must have been larger, perhaps up to 500 metres (1,600 ft).[20] During the coronal passage, it is believed that a significant fraction of the comet's mass was burned off.

In the event that some portion of the nucleus did survive, the eccentricity and inclination of Comet Lovejoy's orbit avoids significant perturbation from planets, which leaves the possibility that the comet may return for another perihelion.[8] Using an epoch 2050 solution, Comet Lovejoy is estimated to have about a 622-year orbit and a return to perihelion around the year 2633.

I would ask wiki do define significant fraction but I can figure that out, a rather large piece.
Here we have a news article about a Comet a year and a half after it first was discovered that clearly states the scientist observed " it disintegrated" after the passing of/through the sun's corona.

I am not discrediting Wiki or BBC just looking for a clear and straight story.

No where are we told on wiki that the comet was destroyed, we are told it continued on its trajectory/orbit of 622 years.

In order to be classified an orbit, the trajectory must be repeated, meaning the Long-period comet that is lovejoy, does, it was calculated or estimated at 622 years.

Kreutz Sungrazers

Larger sungrazers such as the Great Comet of 1843 and C/2011 W3 (Lovejoy) have survived their perihelion passage.

An elliptical orbit calculated by Sekanina and Chodas in 2012 indicates that Comet Lovejoy is a fragment of an unrecorded sungrazer that reached perihelion around 1329. The fragmentation history suggested by these authors is that a parent sungrazer, likely the comet observed in 467 CE, split near the Sun due to tidal forces during its pass. The principal fragment – or a non-tidally fragmented portion of it – returned as the Great Comet of 1106, but a secondary fragment was imparted a longer orbital period and returned about 1329. This secondary also split at perihelion and its principal fragment will return around 2200, likely as a cluster of further fragments. A secondary fragment of this event left on a shorter period that theoretically should bring it back to the inner solar system during the early years of the 21st century. At some point after perihelion, this secondary fragment broke apart due to non-tidal forces and one of the resulting fragments became Comet Lovejoy. Other similar fragments may also exist and might return as sungrazers in the near future.

What this suggest is that Lovejoy is a rare comet indeed. " "Dr Schrijver said: "There have been about 1,600 Sun-grazing comets observed. But all of them vanished and none came out. It's the first one we have seen that was large enough to survive close passage - although not for very long."

I can only wonder how big this original comet must have been

reply to post by whatzshaken


Actually the wiki does suggest that it was destroyed:

Lovejoy Outbound Flight

Some concern was expressed after perihelion that the stresses induced in the comet by its close approach to the Sun might result in its disintegration.[8] That observers were unable to locate a distinct nucleus amidst the more visible tail furthered this idea;[3] using observations from the Pierre Auger Observatory, Zdeněk Sekanina and Paul Chodas determined that, while the nucleus did survive perihelion for several days, following a significant outburst of dust on 19 December, the nucleus underwent a "cataclysmic fragmentation" event on 20 December and completely disappeared.

reply to post by eriktheawful


Okay, so where did it come from then?

An elliptical orbit calculated by Sekanina and Chodas in 2012 indicates that Comet Lovejoy is a fragment of an unrecorded sungrazer that reached perihelion around 1329

List of NON Periodic Comets

C/−43 K1 (Comet Caesar) May 18, 44 BC (China); alternative names in Roman antiquity: sidus Iulium or Caesaris astrum; absolute magnitude: −4.0, one of only five comets known to have had a negative absolute magnitude and possibly the brightest daylight comet in recorded history[4]

X/1106 C1 (Great Comet of 1106) February 2, 1106. One of the Kreutz Sungrazers, split in two.

C/1577 V1 (Great Comet of 1577) (1577 I) November 1, 1577 absolute magnitude −1.8, one of only five comets known to have had a negative absolute magnitude

C/1652 Y1 van Riebeeck, 17 December 1652 (Cape Town, South Africa)

Commet 1882
Comet Ikeya Seki
Great Comets

"An elliptical orbit calculated by Sekanina and Chodas in 2012 indicates that Comet Lovejoy is a fragment of an unrecorded sungrazer that reached perihelion around 1329"

Their claim is valid and holds water on the fact that this sun-grazer in 1329, that has to be a " Greater" comet than Lovejoy which is classified as one, went unrecorded or unrecognized.

Originally posted by whatzshaken
reply to post by eriktheawful

 

Okay, so where did it come from then?

An elliptical orbit calculated by Sekanina and Chodas in 2012 indicates that Comet Lovejoy is a fragment of an unrecorded sungrazer that reached perihelion around 1329

List of NON Periodic Comets

C/−43 K1 (Comet Caesar) May 18, 44 BC (China); alternative names in Roman antiquity: sidus Iulium or Caesaris astrum; absolute magnitude: −4.0, one of only five comets known to have had a negative absolute magnitude and possibly the brightest daylight comet in recorded history[4]

X/1106 C1 (Great Comet of 1106) February 2, 1106. One of the Kreutz Sungrazers, split in two.

C/1577 V1 (Great Comet of 1577) (1577 I) November 1, 1577 absolute magnitude −1.8, one of only five comets known to have had a negative absolute magnitude

C/1652 Y1 van Riebeeck, 17 December 1652 (Cape Town, South Africa)

Commet 1882
Comet Ikeya Seki
Great Comets

"An elliptical orbit calculated by Sekanina and Chodas in 2012 indicates that Comet Lovejoy is a fragment of an unrecorded sungrazer that reached perihelion around 1329"

Their claim is valid and holds water on the fact that this sun-grazer in 1329, that has to be a " Greater" comet than Lovejoy which is classified as one, went unrecorded or unrecognized.

Not sure what your point is. There are different kinds of sungrazing comets:

About 83% of the sungrazers observed with SOHO are members of the Kreutz group.[2] The other 17% contains some sporadic sungrazers, but three other related groups of comets have been identified among them: the Kracht, Marsden and Meyer groups. The Marsden and Kracht groups both appear to be related to Comet 96P/Machholz. These comets have also be linked to several meteor streams, including the Daytime Arietids, the delta Aquariids, and the Quadrantids. Linked comet orbits suggest that both Marsden and Kracht groups have a small period, on the order of five years, but the Meyer group may have intermediate- or long-period orbits. The Meyer group comets are typically small, faint, and never have tails. The Great Comet of 1680 was a sungrazer and while used by Newton to verify Kepler's equations on orbital motion, it was not a member of any larger groups. However, comet C/2012 S1 (ISON) has orbital elements similar to the Great Comet of 1680 and could be a second member of the group.[3]

Source

Sometimes they get destroyed or fragmented. Sometimes they don't:

A sungrazing comet is a comet that passes extremely close to the Sun at perihelion – sometimes within a few thousand kilometres of the Sun's surface. While small sungrazers can be completely evaporated during such a close approach to the Sun, larger sungrazers can survive many perihelion passages. However, the strong evaporation and tidal forces they experience often lead to their fragmentation.

So exactly what is your beef with comet Lovejoy?

Not so much beef as to the fact of where it came from.

These scientist have calculated its orbit of 622 years being a long orbit comet.

Fragmented from a larger comet because of its orbit.

If it did not have an orbit it would have to be classified as an asteroid.

Meaning Lovejoy, being a fragmentation of a previous comet and its orbit around the perihelion ( the sun), and its shear size( it is thought that the nucleus must have been larger, perhaps up to 500 metres (1,600 ft)) to survive its last pass through the corona, being a sun-grazer, fragmented from a much larger sun grazer.

If its orbit is estimated at around 622 years with a degree of difficulty at +/- 10 years, then it fragmented from a comet Great comet roughly around 622 years ago.

But that's not the case, unless it fragmented from the great comet of 1404

An elliptical orbit calculated by Sekanina and Chodas in 2012 indicates that Comet Lovejoy is a fragment of an unrecorded sungrazer that reached perihelion around 1329.

With the size of Lovejoy and its classification of being great comet and the company listed, I find it hard to imaging the comet Lovejoy fragmented from, would go unrecorded.

So it may have fragmented from the great comet of 1404 or is it possible that it was just an asteroid that headed towards the sun.

By defining Lovejoy as an asteroid implies that something set it motion defined by the laws of motion.

reply to post by whatzshaken


Asteroids do have orbits. They orbit the sun.

A comet is considered a comet when it displays a coma or tail. Once it's been identified as such by the IAU, it remains as identified as a comet even after it travels far enough from the sun to no longer have a coma or tail.

Asteroids have a much broader definition. If it's not a planet, moon, comet, meteroid, dwarf planet, kuiper belt object......then it's a "asteroid". That's how the IAU defines them.