April 26, 1983

OUT there, far, far away where Earth is a mere pinpoint of light and the Sun is a pale disk of diminishing consequence, a hardy little spacecraft cruises on and on into the unexplored. No machine of human design has ever gone so far. Pioneer 10 has traveled to the reaches of Pluto, a distance it achieved yesterday, and is advancing toward the edge of the solar system. From out there, now 2.7 billion miles away, Pioneer's eight-watt radio transmitter sends faint messages back to Earth every day, whispers of discovery. The transit time of these reports, traveling at the speed of light, is 4 hours and 16 minutes. And by the time the signals arrive at tracking antennas, they have all but vanished, their strength reduced to 20-billionths of a watt. But scientists with the patience to extract the signals out of the background noise and to decipher their messages are learning for the first time what it is like in the outermost solar system. It is cold and dark and empty, as they knew it must be. A tenuous wind of solar particles, the million-mile-an-hour solar wind, still blows outward. Cosmic rays race inward. A virtual vacuum it may be, but nothingness, it seems, is a relative condition.

A proliferation of laws and regulations controlling the administration of Federal programs continues to cause widespread confusion despite efforts by the Reagan Administration to ease the problem, according to a new nonpartisan study. The Advisory Commission on Intergovernmental Relations, a research agency created by Congress, reached this conclusion in an extensive report on the effects of Federal regulation on state and local governments. An advance copy of the report's findings and recommendations, to be published in several weeks, was made available to The New York Times. The agency found that President Reagan's efforts to reduce burdensome regulations have helped businesses more than state and local governments.

PUBLIC high school students are spending less time on traditional academic subjects and more on ''personal service'' courses such as driver education or home economics than their counterparts did in the 1960's, according to a new study. The study, based on analysis of 8,800 high school transcripts, also found that the proportion of students in academic, or collegepreparatory, programs had declined by a quarter, while the number in the less demanding ''general'' tracks had more than tripled. Cliffor Adelman, the author of the study, described these trends as a ''systematic devaluation'' of the content of American high school curriculums. He said the movement away from college-preparatory courses was ''particularly striking'' because it was occurring even among students who intended to go to college.

President Reagan has agreed to appoint a special envoy to El Salvador to help deal with political and human rights issues there, a White House official said tonight. The appointment, at ''ambassador level,'' was described by Administration sources as a gesture of conciliation toward Congress, and especially toward Representative Clarence D. Long, Democrat of Maryland and chairman of a powerful House appropriations subcommittee. Mr. Long's panel has been holding up action on the President's request for $60 million in military aid for the Salvadoran Government, which is battling a left-wing insurgency. The White House official, who declined to be identified, said he could not disclose the name of the special envoy. Details of the appointment are being included in a letter to be sent to Representative Long, according to Administration officials.

Merrill Lynch & Company - parent of Merrill Lynch, Pierce Fenner & Smith Inc., the nation's largest brokerage firm - announced yesterday that net income more than quadrupled to $126.9 million in the first quarter, a record for that period, as a result of the prolonged stock market rally and record trading volumes. In reporting these results at its annual meeting in New York, Merrill Lynch also announced a two-for-one stock split - its first stock split since becoming a publicly-owned company in 1971 - and an 11 percent increase in its quarterly dividend. The sharp rise in earnings at Merrill Lynch, which has been one of the leaders on Wall Street in diversifying in recent years into other financial services, is in line with similar first-quarter gains at other big brokerage and investment banking concerns. For example, net income at the E.F. Hutton Group rose more than twelvefold, while Paine Webber Inc. gained more than sixfold.