The Total SOlar Eclipse of July 22 2009

The total solar eclipse of July 22 2009 will be visible across south-east Asia and the western Pacific. This will be a spectacular total eclipse, lasting over 6½ minutes at maximum and visible to millions of people over a path up to 258 km wide.

The total eclipse begins just off the coast of India at 00:51:17 UT on July 22, and ends in Polynesia at 04:19:26 UT on July 22. The maximum eclipse is at 02:35:21 UT on July 22, when the total phase will last a stunning 6 minutes and 39 seconds. The partial eclipse will be visible over south-east Asia, Malaysia, Indonesia and the Pacific between 23:58:19 UT on July 21 and 05:12:25 UT on July 22.

More information on this eclipse may be found at Fred Espenak's site. You can plot the eclipse for yourself using the table of mapping co-ordinates.

Please note that these maps are approximate. Check with reliable sources before making travel plans.

Protect Your Eyes!

Overview

This map shows the path of the total eclipse:

Asia

The total eclipse begins at local dawn, 00:51:17 UT on July 22 in the Arabian Sea, just off the coast of India. The path is already over 200km wide here, and the eclipse will last 3 minutes 30 seconds. It crosses over central India, and passes between Nepal and Bangladesh, clips Bhutan and Myanmar, and then enters China. It crosses right over China to the coast around Hangzhou, at around 01:40 UT. By this time the path width is up to 249km, and the total eclipse lasts 5 minutes 56 seconds on the centreline.

Ryukyu

The path of totality passes through the Ryukyu Islands at around 01:56 UT; the path width is 254 km, and the total eclipse will last 6 minutes 20 seconds on the centreline.

Bonin

The Bonin Islands are the next to see the eclipse at around 02:28 UT, just before the maximum eclipse. The path width is 258 km, and the total eclipse lasts 6 minutes and 39 seconds on the centreline.

Polynesia

The total eclipse passes through the islands and atolls of Polynesia from around 03:32 UT to the end of the eclipse at 04:16 UT. As it passes Kwajalein at about 03:40 UT, the path width is down to 252 km, but the total eclipse still lasts 5 minutes and 24 seconds on the centreline.

Binary Star

A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star or secondary. Research between the early 1800s and today suggests that many stars are part of either binary star systems or star systems with more than two stars, called multiple star systems. The term double star may be used synonymously with binary star, but more generally, a double star may be either a binary star or an optical double star which consists of two stars with no physical connection but which appear close together in the sky as seen from the Earth. A double star may be determined to be optical if its components have sufficiently different proper motions or radial velocities, or if parallax measurements reveal its two components to be at sufficiently different distances from the Earth. Most known double stars have not yet been determined to be either bound binary star systems or optical doubles.

Binary star systems are very important in astrophysics because calculations of their orbits allow the masses of their component stars to be directly determined, which in turn allows other stellar parameters, such as radius and density, to be indirectly estimated. This also determines an empirical mass-luminosity relationship (MLR) from which the masses of single stars can be estimated.

Binary stars are often detected optically, in which case they are called visual binaries. Many visual binaries have long orbital periods of several centuries or millennia and therefore have orbits which are uncertain or poorly known. They may also be detected by indirect techniques, such as spectroscopy (spectroscopic binaries) or astrometry (astrometric binaries). If a binary star happens to orbit in a plane along our line of sight, its components will mutually eclipse and transit each other; these pairs are called eclipsing binaries, or, as they are detected by their changes in brightness during eclipses and transits, photometric binaries.

If the orbits of components in binary star systems are close enough they can gravitationally distort their mutual outer stellar atmospheres. In some cases, these close binary systems can exchange mass, which may bring their evolution to stages that single stars cannot attain. Examples of binaries are Algol (an eclipsing binary), Sirius, and Cygnus X-1 (of which one member is probably a black hole). Binary stars are also common as the nuclei of many planetary nebulae, and are the progenitors of both novae and type Ia supernovae.


Black Holes

What Are They?
Black holes are the evolutionary endpoints of stars at least 10 to 15 times as massive as the Sun. If a star that massive or larger undergoes a supernova explosion, it may leave behind a fairly massive burned out stellar remnant. With no outward forces to oppose gravitational forces, the remnant will collapse in on itself. The star eventually collapses to the point of zero volume and infinite density, creating what is known as a " singularity ". As the density increases, the path of light rays emitted from the star are bent and eventually wrapped irrevocably around the star. Any emitted photons are trapped into an orbit by the intense gravitational field; they will never leave it. Because no light escapes after the star reaches this infinite density, it is called a black hole.

But contrary to popular myth, a black hole is not a cosmic vacuum cleaner. If our Sun was suddenly replaced with a black hole of the same mass, the earth's orbit around the Sun would be unchanged. (Of course the Earth's temperature would change, and there would be no solar wind or solar magnetic storms affecting us.) To be "sucked" into a black hole, one has to cross inside the Schwarzschild radius. At this radius, the escape speed is equal to the speed of light, and once light passes through, even it cannot escape.

The Schwarzschild radius can be calculated using the equation for escape speed.
vesc = (2GM/R)1/2
For photons, or objects with no mass, we can substitute c (the speed of light) for Vesc and find the Schwarzschild radius, R, to be
R = 2GM/c2

If the Sun was replaced with a black hole that had the same mass as the Sun, the Schwarzschild radius would be 3 km (compared to the Sun's radius of nearly 700,000 km). Hence the Earth would have to get very close to get sucked into a black hole at the center of our solar system.

If We Can't See Them, How Do We Know They're There?



Since black holes are small (only a few to a few tens of kilometers in size), and light that would allow us to see them cannot escape, a black hole floating alone in space would be hard, if not impossible, to see. For instance, the photograph above shows the optical companion star to the (invisible) black hole candidate Cyg X-1.

However, if a black hole passes through a cloud of interstellar matter, or is close to another "normal" star, the black hole can accrete matter into itself. As the matter falls or is pulled towards the black hole, it gains kinetic energy, heats up and is squeezed by tidal forces. The heating ionizes the atoms, and when the atoms reach a few million degrees Kelvin, they emit X-rays. The X-rays are sent off into space before the matter crosses the Schwarzschild radius and crashes into the singularity. Thus we can see this X-ray emission.

Binary X-ray sources are also places to find strong black hole candidates. A companion star is a perfect source of infalling material for a black hole. A binary system also allows the calculation of the black hole candidate's mass. Once the mass is found, it can be determined if the candidate is a neutron star or a black hole, since neutron stars always have masses of about 1.5 times the mass of the sun. Another sign of the presence of a black hole is random variation of emitted X-rays. The infalling matter that emits X-rays does not fall into the black hole at a steady rate, but rather more sporadically, which causes an observable variation in X-ray intensity. Additionally, if the X-ray source is in a binary system, the X-rays will be periodically cut off as the source is eclipsed by the companion star. When looking for black hole candidates, all these things are taken into account. Many X-ray satellites have scanned the skies for X-ray sources that might be possible black hole candidates.

Cygnus X-1 is the longest known of the black hole candidates. It is a highly variable and irregular source with X-ray emission that flickers in hundredths of a second. An object cannot flicker faster than the time required for light to travel across the object. In a hundredth of a second, light travels 3000 kilometers. This is one fourth of Earth's diameter! So the region emitting the x-rays around Cygnus X-1 is rather small. Its companion star, HDE 226868 is a B0 supergiant with a surface temperature of about 31,000 K. Spectroscopic observations show that the spectral lines of HDE 226868 shift back and forth with a period of 5.6 days. From the mass-luminosity relation, the mass of this supergiant is calculated as 30 times the mass of the Sun. Cyg X-1 must have a mass of about 7 solar masses or else it would not exert enough gravitational pull to cause the wobble in the spectral lines of HDE 226868. Since 7 solar masses is too large to be a white dwarf or neutron star, it must be a black hole.

However, there are arguments against Cyg X-1 being a black hole. HDE 226868 might be undermassive for its spectral type, which would make Cyg X-1 less massive than previously calculated. In addition, uncertainties in the distance to the binary system would also influence mass calculations. All of these uncertainties can make a case for Cyg X-1 having only 3 solar masses, thus allowing for the possibility that it is a neutron star.

Nonetheless, there are now about 10 binaries for which the evidence for a black hole is much stronger than in Cygnus X-1. The first of these, an X-ray transient called A0620-00, was discovered in 1975, and the mass of the compact object was determined in the mid-1980's to be greater than 3.5 solar masses. This very clearly excludes a neutron star, which has a mass near 1.5 solar masses, even allowing for all known theoretical uncertainties. The best case for a black hole is probably V404 Cygni, whose compact star is at least 10 solar masses. With improved instrumentation, the pace of discovery has accelerated over the last five years or so, and the list of dynamically confirmed black hole binaries is growing rapidly.

What about all the Wormhole Stuff?

Unfortunately, worm holes are more science fiction than they are science fact. A wormhole is a theoretical opening in space-time that one could use to travel to far away places very quickly. The wormhole itself is two copies of the black hole geometry connected by a throat - the throat, or passageway, is called an Einstein-Rosen bridge. It has never been proved that worm holes exist and there is no experimental evidence for them, but it is fun to think about the possibilities their existence might create.

Can You Give Me Some More References?

There is quite a bit of black hole theory out there. For more information on it, try these books:

1. Black Holes and Warped Spacetime - William J. Kaufmann, III
2. Lonely Hearts of the Cosmos - Dennis Overbye
3. Black Holes and Time Warps, Einstein's Outrageous Legacy - Kip S. Thorne
4. The Mathematical Theory of Black Holes - S. Chandrasekhar
5. Black Holes and Baby Universes and other Essays - Stephen Hawking
6. Universe - William J. Kaufmann, III
7. Black Holes and the Universe - Igor Novikov

MENGHITUNG KECEPATAN CAHAYA BERDASAR PETUNJUK AL QUR'AN

Kecepatan cahaya adalah kecepatan yang tercepat di jagat raya ini yaitu 299279.5 Km/det. Bisa ditentukan/dihitung dengan tepat berdasar informasi dari petunjuk AL Quran

Mungkin anda pernah tahu bahwa konstanta C, atau kecepatan cahaya yaitu kecepatan tercepat di jagat raya ini diukur, dihitung atau ditentukan oleh berbagai institusi berikut:

• US National Bureau of Standards

C = 299792.4574 + 0.0011 km/det

• The British National Physical Laboratory

C = 299792.4590 + 0.0008 km/det

• Konferensi ke-17 tentang Penetapan Ukuran dan Berat Standar

”Satu meter adalah jarak tempuh cahaya dalam ruang vacum selama jangka waktu 1/299792458 detik".

Tapi anda seharusnya tahu bahwa konstanta C bisa dihitung/ditentukan secara tepat menggunakan informasi dari kitab suci yang diturunkan 14 abad silam: Al Quran, kitab suci umat Islam.

Penemu hitungan ini adalah seorang ahli Fisika dari Mesir bernama DR. Mansour Hassab El Naby

”Dialah (Allah) yang menciptakan matahari bersinar dan bulan bercahaya dan ditetapkanya tempat-tempat bagi perjalanan bulan itu agar kamu mengetahui bilangan tahun dan perhitungan (waktu)" (QS 10:5)

”Dialah (Allah) yang menciptakan malam dan siang, matahari dan bulan. Masing-masing beredar dalam garis edarnya" (QS 21:33).

“Dia mengatur urusan dari langit ke bumi, kemudian (urusan) itu naik kepada-Nya dalam satu hari yang kadarnya seribu tahun menurut perhitunganmu."(QS 32:5)

Berdasar ayat-ayat tersebut diatas, terutama ayat yang terakhir (QS 32:5) dapat disimpulkan bahwa :

Jarak yang dicapai Sang urusan selama satu hari sama dengan jarak yang ditempuh bulan selama 1000 tahun atau 12000 bulan

C . t = 12000 . L

dimana : C = kecepatan Sang urusan

t = waktu selama satu hari

L = panjang rute edar bulan selama satu bulan

Berbagai sistem kalender telah diuji, namun “Sistem kalender bulan sidereal” menghasilkan nilai C yang persis sama dengan nilai C yang sudah diketahui melalui pengukuran

Ada dua macam sistem kalender bulan:

1. Sisyem sinodik, didasarkan atas penampakan semu gerak bulan dan matahari dari bumi.

1 hari = 24 jam

1 bulan = 29.53059 hari

2. Sistem sidereal, didasarkan atas pergerakan relatif bulan dan matahari terhadap bintang dan alam semesta.

1 hari = 23 jam 56 menit 4.0906 detik

= 86164.0906 detik

1 bulan = 27.321661 hari

Sebuah catatan tentang kecepatan bulan (v)

Ada dua tipe kecepatan bulan :

1. Kecepatan relatif terhadap bumi yang bisa dihitung dengan

rumus berikut:

ve = 2 . p . R / T

dimana R = jari-jari revolusi bulan = 384264 km

T = periode revolusi bulan = 655.71986 jam

Jadi ve = 2 * 3.14162 * 384264 km / 655.71986 jam

= 3682.07 km/jam

2. Kecepatan relatif terhadap bintang atau alam semesta. Yang ini yang akan diperlukan. Einstein mengusulkan bahwa kecepatan jenis kedua ini dihitung dengan mengalikan yang pertama dengan cosinus a, sehingga:

v = Ve * Cos a

Dimana a adalah sudut yang dibentuk oleh revolusi bumi selama satu bulan sidereal

a = 26.92848o

Jadi:

C . t = 12000 . L



Ingat !

L = v . T

C . t = 12000 . v . T



Ingat !

v = ve . Cos a

C . t = 12000 . ( ve . Cos a ) . T



Ingat !

ve = 3682.07 km/jam

a = 26.92848o

T = 655.71986 jam

t = 86164.0906 det

C = 12000 . ve . Cos a . T / t



C = 12000 * 3682.07 km/jam * 0.89157 * 655.71986 jam / 86164.0906 det

C = 299792.5 km/det



Bandingkan C (kecepatan sang urusan) hasil perhitungan dengan nilai C (kecepatan cahaya) yang sudah diketahui !

Nilai C hasil perhitungan



C = 299792.5 Km/det

Nilai C hasil pengukuran



® US National Bureau of Standards



C = 299792.4574 + 0.0011 km/det

® The British National

Physical Laboratory



C = 299792.4590 + 0.0008 km/det

® Konferensi ke 17 tentang

Ukuran dan Berat Standar



“Satu meter adalah jarak tempuh cahaya dalam ruang hampa selama 1/299792458 detik "

Kesimpulan

(dari Artikel Prof Elnaby)

“Perhitungan ini membuktikan keakuratan dan konsistensi nilai konstanta C hasil pengukuran selama ini dan juga mnunjukkan kebenaran AlQuranul karim sebagai wahyu yang patut dipelajari dengan analisis yang tajam karena penulisnya adalah Sang pencipta alam semesta.”



Dia mengatur urusan dari langit ke bumi, kemudian (urusan) itu naik kepada-Nya dalam satu hari

yang kadarnya seribu tahun menurut perhitunganmu.

Referensi:

Elnaby, M.H., 1990, A New Astronomical Quranic Method for The Determination of The Greatest Speed C

http://www.islamicity.org/Science/960703A.HTM

Fix, John D., 1995, Astronomy, Journey of the Cosmic Frontier, 1st edition, Mosby-Year Book, Inc., St Louis, Missouri

The Holy Quran online, http://islam.org/mosque/quran.htm

Make A Simple Telescope

Building your own telescope is a fun optical experiment and it can be used to get a better view of the moon and other distant objects.

Materials:
1 .Lens with a short focal length 50 mm double convex lens
2. Lens with a long focal length double convex lens
3. 2 sheets of paper or cardstock
4. Tape


Procedure:
1. Roll up one sheet of paper the short way to form a tube that is about the diameter of the lens with the shortest focal length. This will be the eyepiece. Tape the edges of the eyepiece lens to one end of the tube as neatly as possible.

2. Roll up a second sheet of paper the long way around the tube you just made to form another tube that slides easily over the first one. Tape the second lens neatly to the end of this tube. Now your telescope is ready to be used!

3. Look through the eyepiece and point the other end of your telescope at a distant object. Slide the two tubes in and out until the object comes into focus. You will see the image upside down and magnified 6 times (with a 300 mm lens).

What's Happening?

You have just built a simplified version of a refractor telescope. The lenses at each end work together to focus on a distant object and magnify it so that your eye can see it better. The lens on the outside tube is called the objective lens. This lens collects light from whatever you point the telescope at. The lens at the other end of the telescope is called the eyepiece lens. It takes the light that the objective lens has collected and makes it bigger so that it takes up more space on the part of your eye that allows you to see, so that when you see the image that your telescope is focused on, you see it several times larger than you can see it with your eye alone.

Note: this project can also be done using a 500 mm focal length lens, which will provide 10 times magnification. However, because the focal length is longer, a longer paper tube will be required for the telescope to work. Try using a larger sheet of paper, or taping two sheets together before making the tube.

Soal TIK Kelas X Semester 1

1.Berikut ini adalah jenis perangkat lunak OS, kecuali…
a. Windows
b. Linux
c. DOS
d. UNIX
e. MS Powerpoint

2.Hak untuk mengimport dan mengekspor ciptaan merupakan bagian dari....
a. Hak moral
b. Hak ekonomi
c. Hak eksklusif
d. Hak eksekutif
e. Hak paten

3.Hak salin disebut juga....
a. All right
b. Copysoft
c. Copyleft
d. Literary work
e. Copyright

4.Pembatasan hak cipta diatur dalam pasal....
a. 2,5
b. 41,42,43
c. 10,11,12
d. 14,15,16
e. 45,46

5.Perangkat keras computer yang difungsikan untuk memasukkan data ke dalam memori disebut....
a. Driver
b. Process
c. Peripheral
d. Output device
e. Input device

6.Tombol Ctrl+Alt+Del identik dengan tombol....
a. Power pada CPU
b. Reset pada CPU
c. Wakeup pada keyboard
d. Power pada monitor
e. F12 pada keyboard

7.Dalam perjalanannya, UU No. 6 Tahun 1982 diubah menjadi....
a. UU No. 3 Tahun 1983
b. UU No. 5 Tahun 1987
c. UU No. 7 Tahun 1987
d. UU No. 3 Tahun 1984
e. UU No. 7 Tahun 1986

8.Tim yang bertanggung jawab dalam pelaksanaan perundang- undangan hak cipta, merk dan paten adalah....
a. Densus 88
b. Detasemen A
c. HAKI
d. keppres 34
e. Paspamres

9.Program yang dimasukkkan ke dalam komputer disebut...
a. Brainware
b. Hardware
c. Software
d. User
e. Utility

10.Jarak pandang yang baik dari mata ke monitor adalah....
a. 33-34
b. 36-37
c. 46-47
d. 49-50
e. 51-53

11.1GB (Giga Byte) sama dengan....
a. 1 048 578 kb
b. 1 124 MB
c. 1 073 741 824 Byte
d. 1 073 742 826 Byte
e. 1 024 kb

12.Word yang memberikan fasilitas kemudahan berupa tampilan grafik disebut .....
a. Insert
b. Picture
c. Chart
d. Menu
e. Table

13.Menu yang berguna menampilkan nama program aplikasi dan nama dekumen yang sedang aktif adalah.......
a. Menu bar
b. Title bar
c. Tool bar
d. Scroll bar
e. Picture bar

14.Perintah menyimpan naskah dapat kita lakukan dengan mudah, yaitu menekan ..........
a. Ctrl + S
b. ALT + S
c. Save as
d. Print preview
e. Open

15.Dalam kotak dialog print, yang menentukan jumlah salinan hasil cetakan pada kertas yaitu .......
a. Pege set up
b. Printer Status
c. Propertis
d. Number of copies
e. Printer what

16.Sebelum dicetak di atas kertas, dokumen dapat kita lihat pada layar monitor melalui fasilitas ..........
a. Print priview
b. Save as
c. Copy as
d. Print
e. Open

17.Langkah-langkah untuk mengubah batas kanan atau kiri pada program microsoft word yaitu .......
a. Menu format, page setup, paper size
b. Menu format , Paragraph
c. Menu file, save as
d. Menu file, page setup, margin
e. Menu file, page setup, orientation

18.Selain dengan menggunakan menu File ?Exit, untuk keluar dari program Ms.Word dapat digunakan kunci pintas…
a. F4
b. Esc
c. Alt+F4
d. Ctrl+F4
e. Delete
19.Untuk memperbaiki kesalahan dengan cara melalui sel aktif yaitu ..........
a. F1
b. F2
c. F3
d. F4
e. F5
20.Beberapa bentuk jenis data HH:MM:SS termasuk pada bentuk ..........
a. Teks
b. Waktu
c. Tanggal
d. Angka
d. Harga