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Lightning Rapid advancing column and return streamers According to
Prophet Mohammad Hadith
استخدم
المقالة : Earths Elect-Field.pdf
Hussain Yousef
Omari
Physics Dept./ Mutah
University/ JORDAN
rashed@mutah.edu.jo
A storm: is any disturbed state of an
astronomical body's atmosphere, especially affecting its surface, and strongly implying severe weather. It may be marked by strong wind, thunder and lightning (a thunderstorm), heavy precipitation, such as ice (ice storm), or wind transporting some
substance through the atmosphere (as in a dust storm, snowstorm, hailstorm, etc) ([1]).
العواصف الرعدية
A thunderstorm: ([2])
A thunderstorm, also known as an electrical storm, a lightning storm, or simply a
storm is a form of weather characterized by the presence of lightning and its acoustic effect on the Earth's
atmosphere
known as thunder.[1] The meteorologically-assigned cloud type associated with the
thunderstorm is the cumulonimbus. Thunderstorms are usually
accompanied by strong winds, heavy rain and sometimes snow, hail, or no precipitation at all. Those which cause hail to
fall are known as hailstorms. Thunderstorms may line up in a series or rainband, known as a squall line. Strong or severe thunderstorms may
rotate, known as supercells. While most thunderstorms move with
the mean wind flow through the layer of the troposphere in which they occupy, vertical wind shear causes a deviation in their course
at a right angle to the wind shear direction.
Thunderstorms can generally form and develop in any geographic location,
perhaps most frequently within areas located at mid-latitude when warm moist air front collides
and border cool air fronts.[2] Thunderstorms are responsible for
the development and formation of many severe weather phenomena. Thunderstorms,
and the phenomena that occurs along with it, can produce numerous risks and
hazards to populations and landscapes. Damages that result from thunderstorms
are mainly inflicted by downburst winds, large hailstones, and flash flooding caused by heavy precipitation. Stronger thunderstorm cells are capable of producing tornadoes and waterspouts.
There are four types of thunderstorms: single cell, multicell cluster,
multicell lines, and supercells. Supercell thunderstorms are the
strongest and the most associated with severe weather phenomena. Mesoscale convective systems formed by favorable vertical wind
shear within the tropics and subtropics are responsible for the development
of hurricanes. Dry thunderstorms, with no precipitation, can cause
the outbreak of wildfires with the heat generated from the cloud-to-ground
lightning
that accompanies them. A variety of methods are used to study thunderstorms,
such as weather
radar, weather stations, and video photography. Past
civilizations held various myths concerning thunderstorms and their development
as late as the Eighteenth Century. Other than within the Earth's
atmosphere,
thunderstorms have also been observed on Jupiter and Venus.
Lightning
Stepped leader: قائد (مخطّط) مسار التفريغ
Meaning of Stepped:
Stepped (step), adj.
having a step or steps; formed in a series of steps: a stepped pyramid. (Barnhart,
Clarence L. and Barnhart, Robert K. The
World Book Dictionary, FE Chicago, 1977, two volumes.; Vol. 2; p. 2052)
Stepped 2
Definition: Provided with a step or steps; having a series of offsets (steadiness) or parts resembling the steps of stairs; as, a stepped key. ([3])
Stepped
leader ([4]).
A
stepped leader (possibly also referred to as a step leader) is a path of
ionized air which extends
downward from a thundercloud during the initial
stages of atmospheric breakdown during a lightning strike. Often, there are
multiple, branching stepped leaders. As the step leaders form, these branches
of ionized air form in a stepwise fashion, followed by a short period of
inactivity, until the final step leader reaches the ground, a tall object on
the ground, or a positive streamer extending upward from a
ground object. At this point, the lightning strike begins as an extremely large
negative electric current that flows along the
path defined by the stepped leaders from the thundercloud into to the ground.
This flow of current is often referred to as the return stroke.
Stepped
leaders appear to only move in quantized steps of approximately
50-
Stepped leader—The initial leader of a lightning discharge; an intermittently (from time to
time) advancing column of high ionization and charge that establishes the
channel for a first return stroke.
The abnormal characteristic of this
type of leader is its stepwise growth at intervals of about 50– 100 μs. The velocity of growth during the brief intervals
of advance, each only about 1 μs in duration, is quite high (about 5 ×
The
initial streamer of a lightning discharge; an intermittently advancing column
of high ion density which established the channel for subsequent return streamers
and dart leaders. ([6])
A stepped
leader (possibly also referred to as a step leader) is a path of ionized air which extends downward from a thundercloud during the initial stages of atmospheric
breakdown
during a lightning strike. Often, there are multiple,
branching stepped leaders. As the step leaders form, these branches of ionized
air form in a stepwise fashion, followed by a short period of inactivity, until
the final step leader reaches the ground, a tall object on the ground, or a positive streamer extending upward from a ground
object. At this point, the lightning strike begins as an immensely large
negative electric
current along
the path defined by the stepped leaders, but in the opposite direction: from
ground to cloud. This current is often referred to as the return stroke.
Stepped
leaders appear to only move in quantized steps of approximately 50–100 feet at a time with a 20 to 50 microsecond pause between steps, and may either
branch or proceed directly to ground. ([7])
Characteristics of an `average` lightning flash:-
Stepped leader takes 0.005 secs to develop.
A shock wave of gaseous plasma rushes along this path or channel created
by the stepped leader and large
currents flow to produce temperatures in excess of 30,000 degrees C. This large current
discharge is called the return stroke.
Return stroke takes 0.0001secs (about 1/3 the speed of light).
Return stroke
200,000,000 volts potential over length. Current 50,000 Amps. Core temperature
Lightning
From
Wikipedia, the free encyclopedia
Lightning striking a tower in Banská Bystrica, Slovakia.
Lightning
is an atmospheric discharge of electricity accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms.[1] In the atmospheric electrical discharge, a leader
of a bolt of lightning can travel at speeds of 60,000 m/s
(130,000 mph), and can reach temperatures approaching 30,000°C (54,000°F), hot enough to fuse silica sand into glass channels known as fulgurites which are normally hollow and can
extend some distance into the ground.[2][3] There are some 16 million lightning storms in the world every year.[4]
Lightning
can also occur within the ash clouds from volcanic eruptions, or can be caused by violent forest fires which generate sufficient dust to
create a static
charge.[1][5]
How lightning initially forms is still a matter of debate:[6]
Scientists have studied root causes ranging
from atmospheric perturbations (wind, humidity, friction, and atmospheric
pressure) to
the impact of solar
wind and
accumulation of charged solar particles.[4] Ice inside a cloud is thought to be a key element in lightning
development, and may cause a forcible separation of positive and negative charges within the cloud, thus assisting in
the formation of lightning.[4]
Lightning comes from thunderclouds, known as cumulonimbus, which are
created when hot moist air rises into the atmosphere and condenses. Hot air
rises when heated by the sun, carrying water vapor into the sky. As it rises,
the hot air mingles with colder air, and the moisture condenses into water
droplets. Clouds are created when these water droplets become visible. The
droplets increase in size as the cloud grows and eventually become so heavy
that they fall as rain. Thunderclouds are large, anvil-shaped masses that can
stretch miles across at the base, and reach 
The genesis of lightning is a subject of great
theoretical debate, says Dr. Vladimir Rakov of the Lightning Research Center at
the University of Florida. We know that electrical charges build up within
thunderclouds, but there is no single theory that fully describes why:
وهذا
الاختلاف في منشأ الرعد ينتقل إلى أهل الحديث اختلافا في الحكم على الرواية
التالية:
(أقبلَتِ اليهودُ إلى رسولِ اللهِ صلَّى
اللهُ عليه وسلَّم فقالوا يا أبا القاسمِ إنا نسألُكَ عن خمَسَةِ أشياءَ فإنْ
أنبأْتَنَا بِهِنَّ عرَفْنَا أنَّكَ نَبِيٌّ واتَّبَعْناكَ ... قالوا أخْبِرْنا
مَا هذا الرَّعْدُ قال مَلَكٌ من ملائكةِ اللهِ عزَّ وجلَّ مُوَكَّلٌ بالسحابِ
بيدِهِ أوْ في يدِهِ مِخْراقٌ مِنْ نارٍ يزْجُرُ بِهِ السحابَ يسوقُهُ حيثُ
أمَرَهُ اللهُ عزَّ وجلَّ قالوا فما هذا الصوتُ الذي نسمَعُ قال صوتُهُ قالوا
صَدَقْتَ إنما بقِيَتْ واحِدَةٌ ... ) ([8])
(... قالوا: أخبِرْنا ما هذا الرَّعْدُ؟ قال: ملَكٌ من
ملائكةِ اللهِ عزَّ وجلَّ مُوكَّلٌ بالسَّحابِ بيدِه -أو في يدِه- مِخراقٌ من
نارٍ، يزجُرُ به السَّحابَ، يسوقُه حيثُ أمَر اللهُ، قالوا: فما هذا الصوتُ الذي نسمَعُ؟
قال: صوتُه، قالوا: صدَقتَ، إنَّما بقِيتْ واحدةٌ، وهي التي نُبايِعُكَ إنْ
أخبَرْتَنا بها؛ فإنَّه ليس من نبيٍّ إلَّا له ملَكٌ يأتيه بالخبرِ، فأخبِرْنا من
صاحِبُكَ؟ قال: جِبْريلُ عليه السَّلامُ، قالوا: جِبْريلُ ذاك الذي ينزِلُ بالحربِ
والقِتالِ والعذابِ عدُوُّنا، لو قلتَ: ميكائيلُ الذي ينزِلُ بالرَّحمةِ والنَباتِ
والقَطْرِ؛ لكان؛ فأنزَلَ اللهُ عزَّ وجلَّ: {مَنْ كَانَ عَدُوًّا لِجِبْرِيلَ...}
[البقرة: 97] إلى آخِرِ الآيةِ.) ([9])
One commonly discussed thesis suggests that small cloud particles acquire
a positive charge, while other larger particles become negatively charged.
These particles eventually separate, and the upper part of the cloud becomes
positively charged, while the lower part becomes negatively charged.
The attraction, or electrical potential, between the positive and
negative charges eventually grows strong enough to overcome the air's
resistance to electrical flow. Racing toward each other, the charges connect,
completing an electrical circuit, and discharging the accumulated electricity as
lightning. Cloud-to-cloud lightning is the most common form of electrical
discharge. Only about one-third of all discharges are cloud-to-ground. Bolts
that shoot from cloud-to-air, known as "bolts from the blue," are
even less common, but can strike up to
When the current is discharged, it is accompanied by a flash containing
millions of volts of electricity. This is a huge amount of energy, and the
surrounding air is heated up to 54,000° F, five times hotter than the surface temperature of the Sun. The rapidly
expanding heated air also produces tremendous shock waves, which become audible
as the sound of thunder ([10]) By Micah Fink.
Thunder:
The sound
that follows a flash of lightning and is caused by sudden expansion of the air
in the path of the electrical discharge.
Thunder is the sound that lightning makes. Sounds simple
but why does lightning make a sound. Any sound you hear is made up of
vibrations, the vibrations travel through the air as waves until they reach
your ear.
This means lightning must cause some vibrations.
Lightning is a huge discharge of electricity. When
lightning strikes huge amounts of electricity shoots through the air, this
causes two things to happen.
1. The electricity hits the air and starts it vibrating,
anything vibrating causes a sound.
2.The lightning is also very hot and heats up the air
around it. Hot air gets bigger: it expands. As lightning is very hot the air
gets bigger very quickly and pushes against the air particles starting another
vibration.
These
vibrations are what you are hearing when you hear thunder, the rumbling of
thunder is caused by the vibration or sound bouncing of the ground and the
clouds.
البرق في الأحاديث النبوية الشريفة
(أقبلَتِ اليهودُ إلى رسولِ
اللهِ صلَّى اللهُ عليه وسلَّم فقالوا يا أبا القاسمِ إنا نسألُكَ عن خمَسَةِ
أشياءَ فإنْ أنبأْتَنَا بِهِنَّ عرَفْنَا أنَّكَ نَبِيٌّ واتَّبَعْناكَ ... قالوا
أخْبِرْنا مَا هذا الرَّعْدُ قال مَلَكٌ من ملائكةِ اللهِ عزَّ وجلَّ
مُوَكَّلٌ بالسحابِ بيدِهِ أوْ في يدِهِ مِخْراقٌ مِنْ نارٍ يزْجُرُ بِهِ السحابَ
يسوقُهُ حيثُ أمَرَهُ اللهُ عزَّ وجلَّ قالوا فما هذا الصوتُ الذي نسمَعُ قال
صوتُهُ قالوا صَدَقْتَ إنما بقِيَتْ واحِدَةٌ ... ) ([11])
(... قالوا: أخبِرْنا ما هذا الرَّعْدُ؟ قال: ملَكٌ من
ملائكةِ اللهِ عزَّ وجلَّ مُوكَّلٌ بالسَّحابِ بيدِه -أو في يدِه- مِخراقٌ من
نارٍ، يزجُرُ به السَّحابَ، يسوقُه حيثُ أمَر اللهُ، قالوا: فما هذا الصوتُ الذي
نسمَعُ؟ قال: صوتُه، قالوا: صدَقتَ، إنَّما بقِيتْ واحدةٌ، وهي التي نُبايِعُكَ
إنْ أخبَرْتَنا بها؛ فإنَّه ليس من نبيٍّ إلَّا له ملَكٌ يأتيه بالخبرِ، فأخبِرْنا
من صاحِبُكَ؟ قال: جِبْريلُ عليه السَّلامُ، قالوا: جِبْريلُ ذاك الذي ينزِلُ
بالحربِ والقِتالِ والعذابِ عدُوُّنا، لو قلتَ: ميكائيلُ الذي ينزِلُ بالرَّحمةِ
والنَباتِ والقَطْرِ؛ لكان؛ فأنزَلَ اللهُ عزَّ وجلَّ: {مَنْ كَانَ عَدُوًّا
لِجِبْرِيلَ...} [البقرة: 97] إلى آخِرِ الآيةِ.) ([12])
(أقبلتْ يهودُ إلى النبيِّ صلَّى اللهُ عليهِ وسلَّمَ فقالوا يا
أبا القاسمِ نسألُك عن أشياءَ إن أجَبْتنا فيها اتَّبعناك وصدَّقناك وآمنَّا بك
... قالوا صدقتَ فأخبِرْنا عن الرَّعدِ ما هو قال الرعدُ ملَكٌ من الملائكةِ
مُوكَّلٌ بالسَّحابِ بيدَيه أو في يدِه مِخراقٌ من نارٍ يزجرُ به السحابَ والصوتُ
الذي يُسمعُ منه زَجْرُهُ السَّحابَ إذا زجَرَه حتى ينتهيَ إلى حيث أمرَه) ([13])
(أقبلتْ يهودٌ إلى رسولِ
اللهِ صلَّى اللهُ عليهِ وسلَّمَ فقالوا : يا أبا القاسمِ إنا نَسألُك عن خمسةِ
أشياءَ فإنْ أَنْبَأْتَنا بِهنَّ عرَفْنا أنك نبيٌّ واتَّبعْناكَ ... قالوا :
صدقْتَ قالوا : أخبِرْنا ما هذا الرَّعدُ قال : مَلَكٌ من ملائكةِ اللهِ عزَّ
وجلَّ مُوَكَّلٌ بالسحابِ بيدِهِ أو في يدِه مِخراقٌ من نارٍ يَزجرُ به السحابَ
يَسوقُهُ حيثُ أمرَ اللهُ قالوا : فما هذا الصوتُ الذي يُسمعُ قال : صَوتُهُ قالوا
: صدقْتَ إنَّما بَقِيَتْ واحدةٌ وهي التي نُبَايُعُكَ إن أخْبَرْتَنا بها فإنَّه
ليس من نبيٍّ إلا له مَلَكٌ يَأتيهِ بالخبرِ فأَخْبِرْنا مَن صاحِبُكَ قال :
جِبريلُ عليهِ السلامُ قالوا : جبريلُ ذاك الذي يَنزلُ بالحربِ والقتالِ والعذابِ
عَدُوُّنا لو قلتَ ميكائيلَ الذي ينزلُ بالرحمةِ والنباتِ والقَطْرِ لكانْ فأنزلَ
اللهُ عزَّ وجلَّ : {مَنْ كَانَ عَدُوًّا لِجِبْرِيلَ} إلى آخرِ الآيةِ) ([14])
.
والصوت الذي يسمع منه زجره السحاب إذا زجره حتى
ينتهي إلى حيث أمره .
(الرَّعدُ ملَكٌ من ملائكةِ
اللهِ ، مُوكَّلٌ بالسَّحابِ ، معه مَخاريقٌ من نارٍ ، يسوقُ بها السحابَ حيث شاء
اللهُ) ([15])
(سأَلت اليهودُ النَّبيَّ
صلَّى اللهُ عليه وسلَّم عن الرَّعدِ ما هو قال ملَكٌ من الملائكةِ بيدِه مخاريقُ
من نارٍ يسوقُ بها السَّحابَ حيث شاء اللهُ قالوا فما هذا الصَّوتُ الَّذي نسمعُ
قال زجْرُه بالسَّحابِ إذا زجره حتَّى ينتهيَ إلى حيث أُمِر قالت صدقتَ) (الراوي:
عبدالله بن عباس، المحدث: الشوكاني ، المصدر: فتح القدير، الصفحة أو الرقم : 1/68 ، خلاصة حكم
المحدث : في إسناده مقال )
(أَقْبَلَتْ يهودُ إلى النبيِّ صلَّى اللهُ عليه وسلَّم ، فقالوا:
يا أبا القاسِمِ أَخْبِرْنا عن الرَّعْدِ ، ما هو؟ قال: مَلَكٌ من الملائكةِ
مُوَكَّلٌ بالسَّحَابِ، معه مَخَارِيقُ من نارٍ يَسُوقُ بها السَّحابَ حيثُ شاء
اللهُ. فقالوا: فما هذا الصوتُ الذي
نَسْمَعُ ؟ قال : زَجْرُهُ بالسَّحَابِ إذا زَجَرَه حتى يَنْتَهِيَ إلى حيثُ
أُمِرَت. قالوا: صَدَقْتَ. فقالوا: فأَخْبِرْنا عَمَّا حَرَّمَ إسرائيلُ على
نَفْسِهِ . قال: اشْتَكَى عِرْقَ النَّسَا فلم يَجِدْ شيئًا يُلَائِمُهُ إلا
لُحُومَ الإبِلِ وألبانَها ، فلذلك حَرَّمَها . قالوا : صَدَقْتَ) ([16])
(أقبلَتْ يَهودُ إلى النَّبيِّ صلَّى اللَّهُ علَيهِ وسلَّمَ ،
فقالوا : يا أبا القاسمِ أخبِرنا عنِ الرَّعدِ ما هوَ قالَ ملَكٌ منَ الملائكةِ
موَكَّلٌ بالسَّحابِ معَهُ مَخاريقُ مِن نارٍ يسوقُ بِها السَّحابَ حَيثُ شاءَ
اللَّهُ فقالوا فما هذا الصَّوتُ الَّذي نسمعُ قالَ زَجْرُهُ بالسَّحابِ إذا
زَجرَهُ حتَّى ينتَهيَ إلى حَيثُ أُمِرَ قالوا صدَقتَ. فقالوا فأخبِرنا عمَّا
حرَّمَ إسرائيلُ علَى نفسِهِ قالَ اشتكَى عِرقَ النَّسا فلم يجِدْ شيئًا يلائمُهُ
إلَّا لُحومَ الإبلِ وألبانَها فلذلِكَ حرَّمَها قالوا : صدَقتَ) ([17])
( معه
مخاريق ) : جمع مخراق. وهو في الأصل ثوب يلف ويضرب به الصبيان بعضهم بعضا,
وأراد به هنا آلة تزجر بها الملائكة السحاب . " يسوق ": أي الملك الموكل بالسحاب.
" بها " : أي بتلك المخاريق.
( زجرة ) : أي هو زجرة. (إذا
زجره) : أي إذا ساقه. قال الله تعالى: {
فالزاجرات زجرا } يعني الملائكة تزجر السحاب؛ أي تسوقه. " حتى ينتهي": أي يصل السحاب (
إلى حيث أمر ) (تحفة الأحوذي بشرح
جامع الترمذي).
مِفعال بكسر الميم اسـم
آلـة ([18]):
مثل : منشار ، مسمار ، محراث ، ملقاط ، مثقاب ، مفتاح ، مزمار .
ومنه قوله تعالى : { إن الله لا يظلم مثقال ذرة } 40 النساء
.
وقوله تعالى : { ولا تنقصوا المكيال
والميزان } 84 هود .
وقوله تعالى : { وعنده مفاتح
الغيب } 59 الأنعام .
مِخْراق اسم الآلة من الفعل خرق على وزن مِفْعال
والمخاريق واحدها مخراق ([19]).
هذه المخاريق
يستخدمها ملائكة السّحاب من أجل إحداث فروق جهد هائلة ممّا يتسبّب بحدوث البرق
(الشحنات تخرق مسارها بين السحب التي
تتوسّط هذه المخاريق بسبب فرق الجهد الذي تحدثه الآلات المسماة المخاريق)
. والرّعد هو الصوت الذي يحصل نتيجة
التفريغ الكهربائي بين السّحب . يبدو من
الحديث أنّ فروق الجهد الهائلة والمسببة للتفريغ هي بفعل المخاريق التي تستخدمها
ملائكة السّحاب.
الحديث : (قالوا أخبرنا ما هذا الرعد
قال ملك من ملائكة الله عز وجل موكل بالسحاب بيده أو في يده مخراق من نار يزجر به
السحاب يسوقه حيث أمره الله عز وجل قالوا فما هذا الصوت الذي نسمع قال صوته قالوا
صدقت). ليس معنى الحديث أنّ الرّعد هو ملك.
المعنى إليك تفسير الرّعد: (ملك من ملائكة الله عز وجل موكل بالسحاب بيده
أو في يده مخراق من نار يزجر به السحاب يسوقه حيث أمره الله عز وجل قالوا فما هذا
الصوت الذي نسمع قال صوته قالوا صدقت). (قال
صوته) : الهاء
عائدة على عمليّة الزّجر؛ أي الصوت ناجم عن عمليّة الزّجر التي أحدثها التفريغ
الكهربائي.
الرّعد (الصوت الذي يلي عمليّة التفريغ) وينتج عن عمليّة زجر السّحاب بآلة
المخاريق (جمع مخراق) والمتسبّبة في إحداث فرق الجهد الهائل الذي يحدث البرق ؛
فنسمع الرّعد. وبالمناسبة لا يوجد أيّ
تفسير علمي ثابت يبيّن كيفيّة تنامي فرق الجهد الهائل.
ألم تروا إلى
البرق كيف يمر ويرجع في طرفة عين ؟
(Hast
thou not seen how does the lightning come and return in the blink of an eye?)
- (يجمع الله تبارك وتعالى الناس. فيقوم المؤمنون
حتى تزلف لهم الجنة . فيأتون آدم فيقولون : يا أبانا استفتح لنا الجنة . فيقول :
وهل أخرجكم من الجنة إلا خطيئة أبيكم آدم ! لست بصاحب ذلك . اذهبوا إلى ابني
إبراهيم خليل الله . قال فيقول إبراهيم : لست بصاحب ذلك . إنما كنت خليلا من وراء
وراء. اعمدوا إلى موسى صلى الله عليه وسلم الذي كلمه الله تكليما. فيأتون موسى صلى
الله عليه وسلم فيقول: لست بصاحب ذلك. اذهبوا إلى عيسى كلمة الله وروحه . فيقول
عيسى صلى الله عليه وسلم : لست بصاحب ذلك . فيأتون محمدا صلى الله عليه وسلم.
فيقوم فيؤذن له . وترسل الأمانة والرحم . فتقومان جنبتي الصراط يمينا وشمالا . فيمر أولكم
كالبرق ، قال قلت : بأبي أنت وأمي ! أي شيء كمر البرق ؟ قال : ألم تروا إلى
البرق كيف يمر ويرجع في طرفة عين ؟ ثم كمر الريح
. ثم كمر الطير وشد الرجال . تجري بهم أعمالهم . ونبيكم قائم على الصراط يقول : رب
! سلم سلم . حتى تعجز أعمال العباد . حتى يجيء الرجل فلا يستطيع السير إلا زحفا .
قال وفي حافتي الصراط كلاليب معلقة . مأمورة بأخذ من أمرت به . فمخدوش ناج ومكدوس
في النار . والذي نفس أبي هريرة بيده ! إن قعر جهنم لسبعون خريفا . ) (الراوي: أبو هريرة و حذيفة بن
اليمان المحدث: مسلم - المصدر: صحيح مسلم - الصفحة أو الرقم: 195، خلاصة حكم المحدث: صحيح).
- (يجمع الله الناس فيقول المؤمنون، حين تزلف الجنة،
فيأتون آدم، فيقولون يا أبانا استفتح لنا الجنة، فيقول: وهل أخرجكم من الجنة إلا
خطيئة أبيكم آدم ؟ لست بصاحب ذلك ، إنما كنت خليلا من وراء وراء . اعمدوا إلى ابني
موسى ، الذي كلمه الله تكليما ، فيأتون موسى ، فيقول لست بصاحب ذلك ، اذهبوا إلى
كلمة الله وروحه عيسى ، قال : فيقول عيسى ، لست بصاحب ذلك ، فيأتون محمدا – صلى
الله عليه وسلم – فيقوم فيؤذن له ، وترسل معه الأمانة والرحم ، فيقفان على الصراط
، يمينه وشماله ، فيمر أولكم ، كمر البرق ، قلت : بأبي أنت وأمي : أي
شيء مر البرق قال : ألم تر إلى البرق كيف يمر ، ثم يرجع في طرفة عين ، كمر الريح ،
ومر الطيور ، وشد الرجال ، تجري بهم أعمالهم ، ونبيكم – صلى الله عليه وسلم – قائم
على الصراط ، يقول رب سلم ، سلم ، قال : حتى تعجز أعمال الناس ، حتى يجيء الرجل ،
فلا يستطيع أن يمر إلا زحفا ، قال : وفي حافتي الصراط كلاليب معلقة مأمورة تأخذ من
أمرت به ، فمخدوش ناج ، ومكدوس في النار . والذي نفس أبي هريرة بيده : إن قعر جهنم
لسبعين خريفا
الراوي: أبو هريرة و حذيفة بن اليمان المحدث: ابن خزيمة - المصدر: التوحيد - الصفحة أو الرقم: 600/2، خلاصة حكم المحدث: أشار في المقدمة أنه صح وثبت
بالإسناد الثابت الصحيح).
The rest of
the article is to discuss the following question raise by Prophet's Hadith:
ألم تروا إلى
البرق كيف يمر ويرجع في طرفة عين ؟
(Hast
thou not seen how does the lightning come and return in the blink of an eye?)
هنالك كيفيّة
لمرور البرق:
Lightning has
a step or steps; it is formed in a series of steps. It is Provided with a step or steps; having a series of offsets (steadiness) or parts resembling the steps of stairs ([20]).
Stepped
leader ([21])
A
stepped leader (possibly also referred to as a step leader) is a path of
ionized air which extends
downward from a thundercloud during the initial
stages of atmospheric breakdown during a lightning strike. Often, there are
multiple, branching stepped leaders. As the step leaders form, these branches
of ionized air form in a stepwise fashion, followed by a short period of
inactivity, until the final step leader reaches the ground, a tall object on
the ground, or a positive streamer extending upward from a
ground object. At this point, the lightning strike begins as an extremely large
negative electric current that flows along the
path defined by the stepped leaders from the thundercloud into to the ground.
This flow of current is often referred to as the return stroke.
هنالك مرور و رجوع
في طرفة عين:
Lightning streaks inside a cloud,
between clouds, and from clouds to the ground. Lightning is a flow of electrons
(a negative charge) that zigzags downward in a forked shaped pattern
(scientists call this a step leader).
Stepped
leaders appear to only move in quantized steps of approximately
50-
A lightning flash resolved by Boys camera at 26,000 frames per second
A lightning flash starts downwards as a thin moving leader
with a very luminous tip. The second tip advances in this the stepped leader
by some 20 to 50 meters advance on the first step. The steps, sometimes branching,
stab downwards until near to the ground.
As it nears the earth, a stream of positive charges moves up to the
charge of electrons (negative charge). When they meet, the power flows. We
can't see this because it moves too fast (first stroke). The return flow
(positive charge) moves upward more slowly. This is what we see and call
lightning (return stroke). If there is a flicker, the upward stroke is
repeating the process.
The
return stroke (electrical positive charge that travels from the ground to a
thundercloud) releases tremendous energy, bright light and thunder.
Lightning is, generally, any and all
forms of visible electrical discharge produced by thundershowers. There are
many names. Directly from the Glossary of Meteorology, different forms include:
streak lightning, forked, sheet, heat lightning,
and ball lightning.
|
|
Lightning! |
|
هنالك كيفيّة:
Throughout
history, man has been fascinated by lightning. Ancient peoples thought it was
the work of the gods. In medieval Europe, church bells were rung during
thunderstorms in the belief that it would prevent lightning from striking the
spire (a practice which resulted in the deaths of literally hundreds of bell
ringers). In more recent times, Ben Franklin proved that lightning is merely
electricity with his famous kite experiment and invented the lightning rod in
order to protect buildings from its effects (Mark McEuen).
A Lightning Bolt
The
structure of a typical lightning bolt is surprisingly complex. It begins with a
large thunderstorm. Through a process that is not yet fully understood, charge
separates within the cloud, causing the top to become positively charged and
the bottom negatively charged. This negative charge attracts a
"shadow" of positive charge on the ground below. When enough charge
accumulates, a lightning bolt occurs (Mark McEuen). ([22])
A
lightning bolt happens in a series of stages. First,
a faint step leader emerges from the base of the cloud. It
moves toward the ground in steps of
Multiple-stroke flashes of lightning ([23])
Abstract
Slow-speed rotating all-sky cameras
were used to photograph flashes of lightning in the vicinity of Pretoria and
Johannesburg, South Africa. The frequency distribution of the number of strokes
per flash was determined for 1001 flashes which occurred on a total of 35 days
during five summers. This distribution agrees with other results obtained
recently in the same region of South Africa using other methods, but a higher
proportion (57%) of single-stroke flashes was found compared with previous
results (13%). Individual storms differed widely: some produced only
single-stroke flashes but many multiple-stroke flashes were observed in others.
Flashes with simultaneous multiple grounds were uncommon but one storm produced
a relatively high proportion of such flashes ([24]).
|
Observation
of multiple stroke and multipoint discharges by means of UHF interference ([25]) |
|
Results of interferometric observations
of cloud-to-ground flashes in Darwin (Australia) have been analyzed to
investigate some features of the lightning phenomenon. Our study focused on
comparison between multipoint and multiple negative cloud-to-ground flashes.
The speed of leaders was estimated with submillisecond resolution for both
multipoint and multiple strokes. Leaders preceding the first stroke in
multiple-stroke flashes progress in a stepped fashion, and their behavior
exhibits the same features as leaders in multipoint flashes. The estimated
average speed of the leaders is on the order of 105 m/s, and the mean step
length is found to be |
Review of lightning properties from electric field and TV observations. Vladimir A. Rakov/ Department of Electrical
Engineering, University of Florida, and Gainesville Martin A. Uman, Department
of Electrical Engineering, University of Florida, and Gainesville Rajeev Thottappillil/
Department of Electrical Engineering, University of Florida, Gainesville
From analysis of simultaneous electric field and TV records of 76
negative cloud-to-ground lightning flashes in Florida, various lightning
properties have been determined and several new facets of lightning behavior
inferred. Only 17 % of the flashes were single-stroke flashes, less than half
the commonly claimed percentage (e.g., Anderson and Eriksson, 1980). The
initial electric field peak (and, by inference, current peak) for the only
strokes in single-stroke flashes was smaller than for first strokes in
multiple-stroke flashes. Half of all flashes, single and multiple stroke,
struck ground at more than one point, with the spatial separation between the
channel terminations being up to many kilometers. One third of multiple-stroke
flashes had at least one subsequent stroke whose distance-normalized initial
electric field peak exceeded that of the first stroke in the flash. Thus such
flashes are not unusual, contrary to the implication of most lightning
protection and lightning test standards. Subsequent strokes of the order of 2
through 4 were more likely to create a new channel termination on ground than
strokes of the order of 5 and higher. Further, leaders of lower-order
subsequent strokes following previously formed and not-too-aged (100 ms or less) channels were more likely to show
stepping, as opposed to continuous propagation (i.e., to be dart-stepped
leaders rather than dart leaders), than were leaders of higher-order strokes.
Finally, lower-order subsequent return strokes exhibited a larger initial
electric field peak than did higher-order strokes. The second leader of the
flash (the first subsequent leader) encounters the least favorable propagation
conditions of all subsequent strokes: more than half of the second leaders
either deflected from the previously formed path to ground or propagated in a
stepped, as opposed to a continuous, fashion along the lowest part of that
path. It is important to note that inter stroke intervals preceding second
strokes are similar to or shorter than those preceding higher-order strokes.
These observations indicate that channel conditions for the propagation of a
subsequent leader are determined not just by the immediately preceding channel
heating and cooling processes but rather by the entire channel history. In
particular, the status of the channel apparently depends on the number of
strokes that have participated in its cumulative conditioning. The overwhelming
majority of long continuing currents, those with a duration longer than 40 ms,
were initiated by subsequent strokes of multiple-stroke flashes as opposed to
either the first stroke in a multiple-stroke flash or the only stroke in a
single-stroke flash. Strokes that initiate such long continuing currents were
(1) relatively small (in terms of both return-stroke field peak and, as
determined from an independent study in New Mexico, stroke charge), (2)
followed relatively short inter stroke intervals, and (3) showed a tendency to
be preceded by a relatively large stroke. Millisecond-scale K and M electric
field changes appeared different in terms of both microsecond-scale pulse
content and inter event time intervals. Often no microsecond-scale K and M
field pulses were detected. When they were present, such pulses were highly
variable and sometimes irregular in wave shape, as opposed to the alleged
characteristic K-pulse waveform described by Arnold and Pierce (1964), which
has been extensively used in atmospheric radio-noise studies. There is a
remarkable similarity between many lightning characteristics in Florida and in
New Mexico.
Citation: Rakov, V. A., M. A. Uman, and R. Thottappillil (1994), Review
of lightning properties from electric field and TV observations, J. Geophys.
Res., 99(D5), 10,745–10,750.
(http://www.agu.org/pubs/crossref/1994/93JD01205.shtml)
Subsequent return strokes:
Ref. 
Leaders: A channel of charged air created by
excess electrons in a thunderstorm cloud. A leader reaches from the cloud to
the ground below, looking for positive charges.
Protons:
A sub-atomic (really, really small)
particle that carries a positive energy charge.
Streamers:
A channel of charged air created by protons on the ground. They are created
when leaders are created, and reach from the ground to the sky looking for a
leader to connect with.
Thunder:
The sound that follows a flash of
lightning and is caused by sudden expansion of the air in the path of the
electrical discharge.
1-journal-of-lightning-research-volume_1_2007[1].pdf
---------------------------------------------------
The Cumulo-Nimbus Cloud
The
Cumulo-Nimbus Cloud
Children used to call them Cabbage Clouds as the Cumulus billowed upwards
on a Summer day. When convection carries one high enough its top its drawn
outwards by the winds of the Stratosphere. It has the appearance of the beak of
a blacksmith`s anvil.
Such a cloud is
If the air is free from nuclei, dust, pollen grains, meteoritic detritus,
the water will be liquid and supercool.
The winds inside the cloud reach speeds of hundreds of miles per hour and
circulate the water droplets and ice inside cells/regions within the cloud.
Regions of electrical charge build up within these cells - sometimes
called thunder cells. Some may have net positive charge and some net negative
charge. It is too simplistic to say that there is one polarity at the top of
the cloud and its opposite at the base.
Forms of Lightning
I am referring here only to channel discharges of lightning. We usually see the return stroke oscillating
between cloud and ground and cloud to cloud discharges. Inside the cloud may be
intra-cloud lightning which lights up the cloud like an enormous glow discharge
tube. Discharges may leave the top of the cloud and out into the ionized
regions of the ionosphere.
A fighter pilot who bailed out inside a cumulo-nimbus went
upwards! For three quarters of an hour he was lifted and dropped by the immense
internal winds and described intra cloud lightning as `pillars of blue fire`.
Fork lightning is the name given to the common return discharge cloud to
ground.
Sheet lightning is the lighting up of sky and clouds by unseen fork
lightning.
Ball lightning denied existence for a long time. A.D. Moore told me of
some he had seen. Shortly afterwards my wife was standing at a bus stop when
lightning hit the road about twenty yards away and a blue ball nonchalantly
bounced down the
Bead lightning appears after a particularly powerful fork lightning. It
looks like the lightning discharge channel has broken up into a string of beads
- of plasma.
Ribbon Lightning. Powerful horizontal winds blow the fork lightning
channel sideways. The appearance of the lightning is like a long flat ribbon
reaching from cloud to ground.
From the origin to the discharge of a flash of lightning.
Sources of charge charging processes
Charging Process in Cumulo-Nimbus Decades of investigation have discovered
that:-
Ice impacting on ice produces electricity. Water freezing produces
electricity. Water freezing - remelting - refreezing produces electricity.
Water drops breaking up produce electricity. Droplets drawn out in electric
fields redistribute electricity in themselves and add to total charge.
Ingestion into the cloud of saline jet droplets from the seas and oceans
contribute electricity.
In the Cumulo-Nimbus Cloud the winds, water and temperature generate
electric charge.
The major question is not whether these produce electricity, they have
been investigated at laboratory level and are known to be true, but does the
charging process produce (i) sufficient charge (ii) If so does it do so quickly
enough such that when a thunder cell discharges in lightning it can recharge -
as is observed - within about thirty seconds?
Workman and others investigated warm clouds which also produced
thunderstorms -which brings the ice factor into question.( They also found
Cumulo-Nimbus 15miles high.)
Vonnegut did not accept these processes as being the main contributory
source of electricity and regarded them as interesting secondary sources. He
felt the cloud when it reached a certain height was an electrical conductor on
which charge was induced from the ionized upper atmosphere and Earth`s field.
One thing is certain somehow within the whirling of winds, ice and water
charge accumulation takes place and builds up in `cells` with net pockets of
charge, within the Cumulo-nimbus cloud.
An `Average`Lightning Flash Stephen Gray thought the sounds and
sparks in his electrostatic experiments may well be going on in larger scale in
thunderstorms.
The invention of the Leyden Jar concentrated minds in the same direction.
The discovery that the Leyden Jar spark was oscillatory and not just a simple
discharge led to the thought that lightning too may oscillate between cloud and
ground - assuming of course that lightning was electrical.
Benjamin Franklin with his kite experiments, the experiment at Marly and
others proved that lightning was indeed a gigantic electrical discharge.
But at what voltage? C.T.R. Wilson (Inventor of the Cloud Chamber to
examine ions in the air on Ben Nevis) made the obvious common sense deduction,
namely:
If a potential difference between electrodes of 10,000 volts produces a
spark 1 cm long then a lightning discharge 2km long will have a potential
difference between cloud and ground of:-
2 x 1000(meters) x 100 (cms) x 10,000 (volts) = 2,000,000,000volts.
THE BOYS LIGHTNING CAMERA.
C.V. Boys was a great experimental scientist.
Boys decided to move the lenses in front of a fixed film. The lenses in
the Boys Camera rotated to give the effect of moving the film at 26,000 frames
per second.
A lightning flash resolved by Boys camera at 26,000 frames per second
A lightning flash starts downwards as a thin moving leader with a very
luminous tip. The second tip advances in this the stepped leader by some 20 to
Leader charge is negative and of about 5 coulombs over its entire length. Its downward velocity is
On nearing the ground the intense electric field of the advancing stepped
leader induces an image charge of opposite polarity in the ground and a
streamer is initiated upwards. When the two meet a conducting path is
established between cloud and ground.
A shock wave of gaseous plasma rushes along this path or channel created
by the stepped leader and large currents flow to produce temperatures in excess
of 30,000 degrees C. This large current discharge is
called the return stroke.
Photographic measurements have established the diameter of the stepped
leader channel as being from 1 to
The return stroke may be the
end of the dischage process but very often a second no-stepped leader will
discharge along the ionised channel and initiates a second return stroke. Uman cites one lightning flash
which repeated 26 times before ceasing.
A further phenomena, the M component, is a sudden increase in the
luminosity of the entire channel following the return stroke.
Characteristics of an `average` lightning flash:-
Stepped leader takes 0.005 secs to develop.
Return stroke takes 0.0001secs (about 1/3 the speed of
light).
Return stroke
200,000,000 volts potential over length.
Current 50,000 Amps.
Core temperature
Length
There are 1200 thunderstorms per hour over the Earth`s
surface. Each will have about 1,000 flashes of lightning. A thunder cell within
a cumulo-nimbus cloud recharges in 30 seconds.
Empire State Building
Observations of lightning at the Empire State Building in the 1940s
called into question the `common-sense` estimate of 2,000 million volts potential across a
lightning discharge. Already it had been determined that a charge of 20 to 30 coulombs was being cancelled over an
area of about 100 square km then the electrostatic field must be more in the
range of 300 Volts per cm and not 10,000 Volts per cm predicted by the `common-sense` estimate. This put the
potential in the region of 50 million
volts and not 2000 million volts.
The top of the Empire State Building should have been at 2 million volts with respect to the ground
level. But field values of 100 to 200 Volts per cm were recorded. Also many strokes
were seen to be initiated upwards from the lightning conductors.
Dr.C.E.R. Bruce had been recommended to the Electrical Research
Association by his mentor Sir Edmund Whittaker. He had worked on statistics and
features of the arcs produced by circuit breakers on the National Grid. He was
requested to investigate the earthing of the Grid steel pylons by a wire which
was attached at the highest point and went from pylon to pylon. The idea was a
common-sense one of a kind of continuous lightning conductor.
Bruce began an intensive study of lightning and looked at the results
from Empire State Building. He considered the lower than expected field
potentials and compared these with 10million volt flashes to transmission lines
and moving film camera photographs and measurements of return stroke currents
of 10 to 20,000Amps.
The diagrams show that the stepped leader advances in a thin channel
which has a very luminous tip.
Bruce had his associates set up an experiment in which a steel gramophone
needle represented the Empire State Building. A 2million volt spark was initiated
from the needle to a metal plate 2metres above. From this Bruce determined the
return stroke velocity to be about 30 million meters per second and also made an important observation about the
pre-discharge condition.
The difficulty as he saw it was in trying to explain the spark assumption
which required a build up to 2000 million volts before a lightning discharge. The simple spark discharge
idea did not fit with the complex stepped leader process revealed by Boys and
moving film cameras. The low measurements from the Building observations did
not fit either.
A quick look at Volt Ampere characteristics: -
For a spark discharge the Volt Ampere Characteristic is
Positive. That is as the voltage increase the current increases. In other words
more volts give more amps in current.
For an arc discharge the Volt Ampere characteristic is Negative. That is
as the current increases the voltage either diminishes or remains constant.
More current for the same or less voltage.
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