... M ercury is the closest planet to the Sun and the eighth largest. ... Heraclitus even believed that Mercury and Venus orbit the Sun, not the Earth. ... The perihelion of its orbit precesses around the Sun at a very slow rate. 19th century astronomers made very careful observations of Mercury's orbital parameters but could not adequately explain them using Newtonian mechanics. ... Actually Earth's density is due in part to gravitational compression; if not for this, Mercury would be denser than Earth...

THE PHOTOMETRIC RESEARCHS OF THE MERCURY'S SURFACE BY MEANS OF DIGITAL MODELS. ... The surface brightness of Mercury was measured Danjon (1933, 1949, 1953) and Harris (1961) in phase angle 3o-123o. The analysis of the various data of the integral photometric gives the results of determination of the main photometric constants for Mercury. ... THE PHOTOMETRIC RESEARCHS OF THE MERCURY'S SURFACE: S.G. Pugacheva The surface brightness of the Mercurian images was established on the geologic map Mercury. ...

... Four Planet Sunset . ... Star Forming Region NGC 3582 . ... What's happening in the NGC 3582 nebula? Bright stars and interesting molecules are forming. The complex nebula resides in the star forming region called RCW 57. ... Many bright nebulae and star clusters in planet Earth's sky are associated with the name of astronomer Charles Messier, from his famous 18th century catalog. ... The Nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud. ...

... General information . ... Staff . Research staff . ... Information . ... Historical highlights . Historical research . ... This process is thought to occur in circumstellar disks of gas and dust around young stars on rather short timescales : infrared surveys show that the number of low mass stars with disks drops dramatically for stars older than 10 Myr, suggesting that in order to form large solids before the disk disperses, the growth process has to take place within a few million years. ...

... Venus is the second planet from the Sun and the sixth largest. ... It was subsequently visited by many others (more than 20 in all so far), including Pioneer Venus and the Soviet Venera 7 the first spacecraft to land on another planet, and Venera 9 which returned the first photographs of the surface (left). ... The pressure of Venus' atmosphere at the surface is 90 atmospheres (about the same as the pressure at a depth of 1 km in Earth's oceans). ... There are no small craters on Venus. ... Earth .....

My research efforts have focused on three areas which are: . More than 200 extrasolar planets have been discovered around relatively nearby stars, primarily through the Doppler line shifts owing to the reflex motions of their host stars, and more recently through transits of some planets across the face of the host stars. ... Gravitational microlensing provides a novel technique to look for planets around lens stars, and this is the only technique currently capable of detecting Earth-mass planets. ...

... NASA SPACECRAFT FINDS NEW EVIDENCE FOR WATER ICE ON MERCURY . ... The new data indicate the water ice in Mercury's polar regions, if spread over an area the size of Washington, D.C., would be more than 2 miles thick," said David Lawrence, a MESSENGER participating scientist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., and lead author of one of three papers describing the findings. ... Water ice concentrations are derived from the hydrogen measurements. ...

Deep Time: Earth's history and future By Colin Johnston, Armagh Planetarium Earth 4.54 billion years ago Forms in Sun's protoplanetary disc S un Elsewhere in Solar System Other planets form. ... Hot and airless Sun a subgiant, diameter 1.5 its current value, 2 6.4 billion years from no w ? ... Earth cools 20 million years later? ... Core temperature about 55 million°C, helium flash, followed by the Sun shrinking Sun is 10 times its current diameter, luminosity 20-50% current value. ...

Ganymede is the largest moon in our solar system, larger even than the planets Pluto and Mercury. ... Ganymede's surface consists of two main types of terrain: old, dark polygonal units, and young, bright valleys and ridges (see figure 11 ). ... In a similar way, hitting a large block of ice with a hammer makes white marks. ... Ganymede as seen by Voyager 2. ... Because Voyager couldn't spot any large impact craters, scientists have concluded that the moon's surface is young. ... Moon . ... Europa . ...

... Contents . ... Sidereal time . ... Ephemeris of the Sun . ... Aberration, parallax, mean longitude of the Sun, obliquity of the ecliptic, nutation in obliquity . ... Mean longitude of the Moon, mean elements of the Moon's orbit and equator . ... Ephemeris for physical observations of the Sun . ... Ephemeris for physical observations of the Moon . ... Conversion of mean time to sidereal time (with accuracy 0.01 s ) . ... Conversion of sidereal time to mean time (with accuracy 0.01 s ) . ...

... Bad Astronomy . ... Bitesize Astronomy . ... Bad Astro Store . ... Site Info . ... It is from from Voyager 1 and shows a whopping big impact crater dominating the profile of the moon. Note that Mimas is about 400 kilometers across (about 250 miles). ... The wall around the crater is 5 kilometers high, and that central peak rises 6 kilometers above the surface (many impact craters have a large central peak which is caused by a pressure rebound from the impact). ... 2008 Phil Plait. ...

Pulkovo Database of Observations of Planets and Their Satellites . Select object, time interval and type of observations . ... First year (optional) . Last year (optional) . ... satellite relative to planet . satellite relative to another satellite . ... Select database . ...

... Go directly to the moons of: . Mercury Venus Mars Jupiter Saturn Uranus Neptune Pluto . Go directly to the surface features of Earth's Moon and Mars . Planet & Moons . Pronunciation . ... Mercury . ... Mars: . 2 moons . ... Jupiter: . ... Neptune: . ... 1 moon . ...

. Mars has become the center of intense interest since the Martian Meteorite results were announced. Currently there is a lively debate whether or not primitive life formed there or not.

... Billions of years ago the surface of Mars looked very different than it does today. Where there is now only a dry red desert, there was once an vast ocean that covered about 20% the planet's surface. That means it covered more of the surface of Mars than the Atlantic Ocean covers on Earth! ... So, by looking at how much heavy water is in Mars' atmosphere in comparison to the lighter kind, we can tell how much normal water the planet has lost into space. ...

Kepler's Laws Kepler was an assistant to Tycho Brahe. Brahe had made extensive observations of the known planets and had accurately mapped the motion of these planets as they passed across the sky for a number of years. ... The orbits of the planets are ellipses with the sun at one of the foci. ... Look at the distance between the discs. ... Kepler's Laws All bodies sweep out equal areas in equal times If we look at the planets we have already seen that the planets change speed in their orbit. ...

Computer Ephemeris. Ephemeris for physical observations of the planets. Explanations. Each row of the table contains for date specified at 0h of Time Terrestrial Dynamical: . ... position angle of axis of planetary rotation (degrees) - 'P', . ... illumanated part of the disk - k, . ... position angle of disk point with minimal illumination (degrees), . longitude of central meridian of the disk (degrees) - 'merid1' - system I and so... phase correction (degrees). ...

... The planets differ greatly in size and properties, and their fields differ too. ... In 1959, after the Earth's radiation belt had been discovered, Frank Drake observed Jupiter and concluded from the relative intensities in a range of wavelengths that the signal was probably emitted by electrons trapped in a strong magnetic field. Then in 1973 the space probe Pioneer 10 passed by Jupiter and found there, sure enough, an enormous planetary magnetic field and a very intense radiation belt. ...

. This illustration provides a comparison for how big the moons of Mars appear to be, as seen from the surface of Mars, in relation to the size that Earth's moon appears to be when seen from the surface of Earth. Earth's moon actually has a diameter more than 100 times greater than the larger martian moon, Phobos. However, the martian moons orbit much closer to their planet than the distance between Earth and Earth's moon. // NASA/JPL-Caltech/Malin Space Science Systems/Texas A Univ.