Astronomers theorize that a collision with a smaller companion galaxy near the core of the main galaxy could have led to the unusual spiral structure.

Astronomers estimated that the visible fragments of SL9 ranged in size from a few hundred metres to two kilometres across, suggesting that the original comet may have had a nucleus up to acrosssomewhat larger than Comet Hyakutake, which became very bright when it passed close to the Earth in 1996.

Astronomers had expected to see the fireballs from the impacts, but did not have any idea in advance how visible the atmospheric effects of the impacts would be from Earth.

Astronomers have determined that it is between 6, 000 and 8, 000 years old ; it is approximately one light-year in diameter.

* Astronomers have reported that spectral class T brown dwarves ( the ones with the coolest temperatures ) are colored magenta because of absorption by sodium and potassium atoms of light in the green portion of the spectrum.

Astronomers have made great efforts to find and analyse brown dwarfs in the Pleiades and other young clusters, because they are still relatively bright and observable, while brown dwarfs in older clusters have faded and are much more difficult to study.

Astronomers do believe that the Ordovician – Silurian extinction, the third most destructive extinction on Earth, might have been due to a GRB.

Astronomers think that the sun had about 70 – 75 % of the present luminosity, yet temperatures appear to have been near modern levels even within 500 Ma of Earth's formation, which is puzzling ( the faint young sun paradox ).

Astronomers have used the name of Quaoar to name a large object in the Kuiper belt, 50000 Quaoar ( 2002 ), and the name of Weywot to name its satellite ( 2009 ).

Astronomers have long believed that the Magellanic Clouds have orbited the Milky Way at approximately their current distances, but evidence suggests that it is rare for them to come as close to the Milky Way as they are now.

Astronomers have directly observed protoplanetary disks, brown dwarfs, intense and turbulent motions of the gas, and the photo-ionizing effects of massive nearby stars in the nebula.

Astronomers have long thought it was quite likely that many undiscovered dwarf stars exist within 20 light years of Earth, as stellar population surveys show the count of known nearby dwarf stars to be lower than otherwise expected and these stars are dim and easily overlooked.

Astronomers have speculated that either intense star formation regions or active galactic nuclei ( which contain supermassive black holes ) may be responsible for the intense dust heating that produces this emission, although the general consensus is that both may be present in most ULIRGs.

Astronomers have paid particular attention to whether earthshine measurement can detect the red edge, a spectral feature that is due to the plants.

Astronomers have postulated that this fluctuating emission comes from the first known intermediate-mass black hole, of roughly 200 to 5000 solar masses.

Astronomers using the Hale Telescope have discovered distant objects at the edges of the known universe called quasars and have given us the first direct evidence of stars in distant galaxies.

Astronomers announce this as evidence that the theory of the cosmological constant proposed, but later discarded, by Einstein may have been right after all.

Astronomers usually express distances in units of parsecs ; light-years are used in popular media, but almost invariably values in light-years have been converted from numbers tabulated in parsecs in the original source.

Astronomers have a number of observational tools that they can use to make measurements of the heavens.

Astronomers have dubbed this object as the Twin Jet Nebula because of the polar jets believed to cause the shape of the lobes.

Astronomers in societies which have alternate traditional names for the planets may use those names in scientific discourse.

Astronomers who had been studying the planet Venus chose Rittenhouse to study the transit path of Venus in 1769 and its atmosphere.

Where possible, individual astronomers have been categorized under their individual nationalities under " Astronomers by nationality ".

Astronomers have been discovering " extrasolar " planets ( planets that orbit stars other than the Sun ) the last few years.

Astronomers have been unable to observe Sgr A * in the optical spectrum because of the effect of 25 magnitudes of extinction between the source and Earth.

Norman Sperling is a recipient of the National Service Award by the Western Amateur Astronomers, and had been recognized " For special and meritorious service for his unusual dedication and service to the astronomical community in all areas of astronomy " by the Astronomical Association of Northern California.

Astronomers were surprised at this as the Moon is the only large object in orbit around the Earth and anything else would have been ejected long ago due to perturbations with the Earth, the Moon and the Sun.

Astronomers theorized that it could have been a supernova, but the unique filtering properties of the foreground galaxy made it difficult to decide definitively.

" Astronomers have noted that the observation may have been of a reflection of a bright star which lies two degrees to the north of NGC 56's location.

Astronomers inferred that the star had been a red supergiant, and had shed a large amount of matter into space, before evolving into a blue supergiant and exploding.

When Pluto was first discovered, it was initially known as Planet X. Astronomers had been searching for another planet past Neptune, hoping to solve the dilemma of its rather irregular orbit.

Astronomers can determine the mass, age, chemical composition and many other properties of a star by observing its spectrum, luminosity and motion through space.

Astronomers considered many distinct classes of objects, including white dwarfs, pulsars, supernovae, globular clusters, quasars, Seyfert galaxies, and BL Lac objects.

Astronomers use many radio telescopes to look up at objects such as pulsars in our own Galaxy and at distant radio galaxies up to about half the distance of the observable sphere of our Universe.

Astronomers observe a wide range of astronomical sources, including high-redshift galaxies, AGNs, the afterglow from the Big Bang and many different types of stars and protostars.

Altho ' the Distinction of Stars into six Degrees of Magnitude is commonly received by Astronomers ; yet we are not to judge, that every particular Star is exactly to be ranked according to a certain Bigness, which is one of the Six ; but rather in reality there are almost as many Orders of Stars, as there are Stars, few of them being exactly of the same Bigness and Lustre.

Astronomers for many years ruled out red dwarfs as potential abodes for life.

Astronomers now generally regard all the early reports of detection as erroneous.

Astronomers believe that the matter composing the Oort cloud formed closer to the Sun and was scattered far out into space by the gravitational effects of the giant planets early in the Solar System's evolution.

Astronomers use the Julian calendar for years before 1582, including this year 0, and the Gregorian calendar for years after 1582 as exemplified by Jacques Cassini ( 1740 ), Simon Newcomb ( 1898 ) and Fred Espenak ( 2007 ).

These productions include the official International Year of Astronomy ( IYA2009 ) planetarium show " We are Astronomers " which was funded by the UK Science and Technology Facilities Council ( STFC )

Another significant project funded by PWAP is the Astronomers Monument at Griffith Observatory in Los Angeles.

The only " signature " on the Astronomers Monument is " PWAP 1934 " referring to the program which funded the project and the year it was completed.