OrbitalHub

NASA dixit:

“A new model is bringing scientists a step closer to understanding the kinds of light signals produced when two supermassive black holes, which are millions to billions of times the mass of the Sun, spiral toward a collision. For the first time, a new computer simulation that fully incorporates the physical effects of Einstein’s general theory of relativity shows that gas in such systems will glow predominantly in ultraviolet and X-ray light.

Supermassive mergers will be much more difficult to find than their stellar-mass cousins. One reason ground-based observatories can’t detect gravitational waves from these events is because Earth itself is too noisy, shaking from seismic vibrations and gravitational changes from atmospheric disturbances. The detectors must be in space, like the Laser Interferometer Space Antenna (LISA) led by ESA (the European Space Agency) and planned for launch in the 2030s. Observatories monitoring sets of rapidly spinning, superdense stars called pulsars may detect gravitational waves from monster mergers. Like lighthouses, pulsars emit regularly timed beams of light that flash in and out of view as they rotate. Gravitational waves could cause slight changes in the timing of those flashes, but so far studies haven’t yielded any detections.”

New Simulation Sheds Light on Spiraling Supermassive Black Holes

Video Credit: NASA

NASA dixit:

“Using NASA’s Hubble and Kepler space telescopes, astronomers have uncovered tantalizing evidence of what could be the first discovery of a moon orbiting a planet outside our solar system. This moon candidate, which is 8,000 light-years from Earth in the Cygnus constellation, orbits a gas-giant planet that, in turn, orbits a star called Kepler-1625. Researchers caution that the moon hypothesis is tentative and must be confirmed by follow-up Hubble observations.

Since moons outside our solar system – known as exomoons – cannot be imaged directly, their presence is inferred when they pass in front of a star, momentarily dimming its light. Such an event is called a transit, and has been used to detect many of the exoplanets cataloged to date. However, exomoons are harder to detect than exoplanets because they are smaller than their companion planet, and so their transit signal is weaker when plotted on a light curve that measures the duration of the planet crossing and the amount of momentary dimming. Exomoons also shift position with each transit because the moon is orbiting the planet.”

Astronomers Find First Evidence of Possible Moon Outside Our Solar System

Evidence for a large exomoon orbiting Kepler-1625b

Evidence for an Exomoon around Kepler-1625b

Video Credit: NASA Goddard

ESA dixit:

“When a small Solar System body such as a moon or an asteroid passes in front of a star and temporarily blocks its light, the occultation is an extraordinary chance for astronomers to study the properties of the foreground object. And, of course, the more accurate the prediction of both objects’ positions on the sky, the better the observations. This is why, when a group of astronomers were planning to observe the rare occultation of a distant star by Neptune’s moon Triton on 5 October 2017, they made a special request to the Gaia team.

The astronomers, led by Bruno Sicardy from Pierre and Marie Curie University and the Observatory of Paris, France, had used all available observations to compute the path that the moon’s shadow would sweep across our planet. Within less than three minutes, the occultation would first cross Europe and North Africa, rapidly moving towards North America. They knew that somewhere, within this couple of thousand kilometre-wide stretch, would lie a very special thin strip, only about 100-km across. Observers situated on this strip would be perfectly aligned with both Triton and the distant star, and therefore able to see the so-called central flash. This sharp brightening of the star happens half way through the occultation, and is caused by focussing of the starlight by deep layers in the moon’s atmosphere – about 10 km above surface. The central flash contains all-important information to study the profile of Triton’s atmosphere and the possible presence of haze in it.”

Chasing a Stellar Flash with Assistance from Gaia

Catching the Shadow of a Neptunian Moon

Video Credit: ESA

ESA dixit:

“Rosetta launched in 2004 and travelled for ten years to its destination before deploying the lander Philae to the comet’s surface. Following the comet along its orbit around the Sun, Rosetta studied the comet’s surface changes, its dusty, gassy environment and its interaction with the solar wind. Even though scientific operations concluded in September 2016 with Rosetta’s own descent to the comet’s surface, analysis of the mission’s data will continue for decades.”

Video Credit: ESA

Low frequency sounds of the Sun explained by NASA heliophysicist Alex Young.

Video Credit: NASA Goddard

Wikipedia dixit:

“The Transiting Exoplanet Survey Satellite (TESS) is a space telescope for NASA’s Explorers program, designed to search for exoplanets using the transit method in an area 400 times larger than that covered by the Kepler mission. It was launched on April 18, 2018 atop a Falcon 9 rocket. During its primary mission, it is expected to find more than 20,000 exoplanets compared to about 3,800 exoplanets known when it launched.

The primary mission objective for TESS is to survey the brightest stars near the Earth for transiting exoplanets over a two-year period. The TESS satellite uses an array of wide-field cameras to perform a survey of 85% of the sky. With TESS, it is possible to study the mass, size, density and orbit of a large cohort of small planets, including a sample of rocky planets in the habitable zones of their host stars. TESS will provide prime targets for further characterization by the James Webb Space Telescope, as well as other large ground-based and space-based telescopes of the future. While previous sky surveys with ground-based telescopes have mainly detected giant exoplanets, TESS will find a large number of small planets around the nearest stars in the sky. TESS records the nearest and brightest main sequence stars hosting transiting exoplanets, which are the most favorable targets for detailed investigations.

TESS uses a novel highly-elliptical orbit with an apogee approximately at the distance of the Moon and a perigee of 108,000 km, above the geosynchronous satellites. TESS orbits Earth twice during the time the Moon orbits once, a 2:1 resonance with the Moon. The orbit is expected to remain stable for a minimum of 10 years.”

Video Credit: NASA Goddard