Our Amazing Solar System by NASA and STScI (adapted excerpt) Very little was known about Neptune and its atmosphere until Voyager 2 arrived at the planet in 1989. Voyager revealed a banded cloud structure and a storm that was called the Great Dark Spot. Neptune's axis is tilted similar to Earth's. Neptune therefore exhibits seasonal changes. However, the seasons on Neptune last for decades, not months as on Earth. In fact, Neptune has only completed one orbit of the Sun since its discovery In 1843. It is remarkable that Neptune exhibits any evidence of seasonal change at all, given that the Sun, as viewed from the planet, is 900 times dimmer than it is from Earth. Still, Hubble, a deep space telescope, has been able to observe such changes. Hubble's near-infrared capabilities allow the telescope to observe high-altitude clouds on Neptune that are useful for tracking seasonal changes. In fact, Hubble Images taken in the late 1990s showed that cloud bands on Neptune were getting wider and brighter were considered the first observational evidence that the planet undergoes a change of seasons. In 2002, astronomers using Hubble noted that the abundance of high-altitude clouds Increased the planet's brightness from observations made in the late 1990s. Astronomers consider this brightness increase a sign of seasonal change. Hubble studies show that Neptune has a nearly constant brightness at low latitudes (near the equator). This supports the idea that the observed changes are seasonal in nature, because seasonal effects would be minimal near the equator and most evident at high latitudes.

Passage 2
About the Hubble Space Telescope by NASA and STScI (excerpt) Orbiting 360 miles above Earth, the Hubble Space Telescope is positioned high above the blurring effects of the atmosphere. From this vantage point, it captures Images with 10 times the typical clarity of any ground-based telescope and views not only visible light, but also wavelengths of near-infrared and ultraviolet light that cannot reach Earth's surface. To operate from orbit, the observatory works like any other scientific or Imaging spacecraft: It converts the optical data It collects into electrical signals that are transmitted back to Earth. It must also withstand the airless, high-radiation, and harsh thermal environment of space. Unlike most other spacecraft, however, Hubble was designed to be serviced periodically by astronauts and so was built with modular components that are astronaut-friendly to handle and replace. This design strategy has enabled it to operate longer than ordinary spacecraft and to benefit from the technological advancements of the last two decades. Astronauts have visited the telescope five times to upgrade its computers, mechanisms, and instruments. These servicing missions have kept the observatory at the forefront of discovery by providing it with increasingly sensitive and accurate components. The last of these servicing calls was in May 2009.

Identify the approach of each passage
1.has a scientific approach
2.discusses product engineering
3.discusses history
4.is formal

Passage 1. | Passage 2. | Both

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